Asia

Jeff M. Smith, Bryan Burack, Andrew J. Harding, and Allen Zhang

Regional Overview

Asia has always been vital to the protection and advancement of America’s economic and security interests. Since the 19th century, it has been U.S. policy to prevent the rise of an antagonistic regional hegemon in Asia, whether it was Imperial Japan, the Soviet Union, or China itself.

In the 21st century, Asia’s importance to the United States has only grown. Asia is a key source of trade and natural resources and plays a crucial role in countless global supply chains. The sea lines of communication that run through the Pacific and Indian Oceans host the vast majority of seaborne global trade. As of February 2025, half of America’s top 12 trading partners, including China, Japan, South Korea, Vietnam, India, and Taiwan, were found in Asia.[REF]

The U.S. also has several key security interests in Asia: a variety of treaty allies and important security partners. The region has several of the world’s largest and most capable militaries, including those of China, India, Japan, Russia, Pakistan, and North and South Korea. Five Asian states—China, North Korea, India, Pakistan, and Russia—also possess nuclear weapons.

The region is a core American security focus because:

• It is home to America’s top external security threat—China.
• It is home to several critical trading and treaty allies as well as India, potentially a major geostrategic partner.
• It is characterized by several military flash points that could escalate to a nuclear exchange, numerous territorial and maritime disputes, and long-standing rivalries.

China’s rapid military modernization and technological development, along with its air and sea incursions around Taiwan, have generated increased concern about the potential for military conflict in the Taiwan Strait. The situation on the Korean Peninsula remains perpetually tense as Pyongyang expands its missile arsenal and tests its increasingly capable long-range missiles. China’s growing and increasingly potent naval capabilities, enhanced by a massive maritime militia, are also generating alarm in Washington and among numerous treaty allies and security partners. The disputed China–India border has grown considerably more volatile since a series of violent and deadly confrontations in 2020. And in May 2025, Pakistan’s terrorist attack into India nearly triggered a war.

Attempts to build a united security architecture among allies in the region are complicated by the lack of a robust NATO-like political–security organization. Instead, the Asian security landscape for the United States is shaped by a combination of bilateral alliances. In recent years, these core aspects of the regional security architecture have been supported by “minilateral” security partnerships: the U.S.–Japan–Australia and India–Japan–Australia trilaterals; the U.S.–Japan–Australia–India quadrilateral dialogue (popularly known as the Quad); the Australia–United Kingdom–United States (AUKUS) agreement; and growing U.S.–Japan–South Korea trilateral cooperation. These efforts have often been stymied by limited shared interests, disagreement on appropriate measures to counter the China threat, and historical animosities between nations (e.g., Japan and South Korea).

The Association of Southeast Asian Nations (ASEAN) is a loose agglomeration of disparate states that has succeeded in expanding economic linkages among themselves over the past 50 years through a range of economic agreements like the ASEAN Free Trade Area (AFTA). ASEAN also serves as the convening force behind the patchwork regional diplomatic and security architecture like the ASEAN Regional Forum (ARF) and ASEAN Defense Ministers Meeting-Plus (ADMM-Plus). The South Asia Association of Regional Cooperation (SAARC), which includes Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka, has been less effective because of the lack of regional economic integration and the historical rivalry between India and Pakistan.

As noted, Asia is not undergirded by any significant economic architecture. Despite substantial trade and expanding value chains among the various Asian states, formal economic integration is limited. There are, however, many trade agreements among the nations of the region and among these nations and countries outside of Asia. The most prominent are the 15-nation Regional Comprehensive Economic Partnership (RCEP) and the 11-nation Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), neither of which includes the U.S. or India.

Important Alliances and Bilateral Relations in Asia

The keys to a robust U.S. security presence in the Western Pacific are America’s alliances with Japan, the Republic of Korea (ROK or South Korea), the Philippines, Thailand, and Australia. These formal alliances are supplemented by close security relationships with New Zealand and Singapore, an emerging strategic partnership with India, and evolving relationships with Southeast Asian partners like Vietnam, Malaysia, and Indonesia. The United States also has a robust unofficial security and economic relationship with Taiwan.

The U.S. improves interoperability by sharing common weapons and systems with many of its allies, many of which field F-15, F-16, and F-35 combat aircraft and employ LINK-16 data links among their naval forces. Australia, Japan, and South Korea are partners in production of the F-35 Joint Strike Fighter, and all three countries have taken delivery of the aircraft. Partners like India and Australia operate American-made P-8 maritime surveillance aircraft and C-17 transport aircraft.

In addition, several “foundational” military agreements with regional partners and allies allow for the sharing of encrypted communications data and equipment, access to each other’s military facilities, and the ability to refuel each other’s air and naval vessels in theater utilizing Acquisition and Cross-Servicing Agreements (ACSAs). In the event of conflict, a patchwork of intelligence-sharing agreements enables the sharing of information in such key areas as air defense and maritime domain awareness. This advantage is enhanced by the ongoing range of bilateral and multilateral exercises that acclimate various forces to operating together and familiarize American and local commanders with each other’s standard operating procedures (SOPs) as well as training, tactics, and (in some cases) war plans.

While it does not constitute a formal alliance, in November 2017, Australia, Japan, India, and the United States reconstituted the Quad,[REF] a forum for the four countries to meet at various levels and in venues to discuss ways to strengthen strategic cooperation and combat common threats. In 2019, the group held its first meeting at the ministerial level and added a counterterrorism tabletop exercise to its agenda.[REF] In 2020, officials from the four countries participated in a series of conference calls to discuss responses to the COVID-19 pandemic that also included government representatives from New Zealand, South Korea, and Vietnam.[REF] In March 2021, the leaders of the four nations held their first virtual summit, marking a new level of interaction.[REF] In September 2021, the four leaders held the first in-person Quad summit, which was followed by a second in-person summit in 2022.[REF] Quad engagement has remained a leading component of U.S. engagement in Asia. In January 2025, Secretary of State Marco Rubio met with his Quad counterparts as one of his first official acts on his first day in office.[REF]

Japan. The U.S.–Japan defense relationship is the cornerstone of America’s network of relations in the Western Pacific. The U.S.–Japan Treaty of Mutual Cooperation and Security, signed in 1960, provides for a deep alliance between two of the world’s largest economies and most sophisticated military establishments.

The United States maintains “approximately 60,000 military personnel” and “7,000 Department of Defense [now Department of War] civilian and contractor employees” in Japan under the rubric of U.S. Forces Japan (USFJ).[REF] These forces include, among other things, a forward-deployed carrier battle group centered on the USS Ronald Reagan, an amphibious group at Sasebo centered on the LHA-6 America, an aviation-optimized amphibious assault ship, and the bulk of the Third Marine Expeditionary Force (III MEF) on Okinawa. U.S. forces exercise regularly with their Japanese counterparts, and this collaboration has expanded in recent years to include joint amphibious exercises as well as air and naval exercises.

The American presence is supported by a substantial American defense infrastructure throughout Japan, including Okinawa. These bases provide key logistical and communications support for U.S. operations throughout the Western Pacific, cutting travel time substantially compared with deployments from Hawaii or the U.S. West Coast. They also provide key listening posts for the monitoring of Russian, Chinese, and North Korean military operations. This capability is enhanced by Japan’s growing array of space systems including new reconnaissance satellites.

During bilateral Special Measures Agreement negotiations, the first Trump Administration sought a 400 percent increase in Japanese contributions for the cost of stationing U.S. troops in Japan. Late in 2021, it was reported that Japan had agreed to “ramp up its annual host-nation support for U.S. forces stationed in Japan.”[REF]

Despite developing a formidable military force, Japan still relies heavily on the United States and Washington’s extended deterrence guarantee of nuclear, conventional, and missile defense forces for its security. In March 2025, Japan established a Joint Operations Command to unify command of its ground, naval, and air forces.[REF] Previously, the Self-Defense Forces were stovepiped with insufficient ability to communicate, plan, or operate across services. Japan’s inability to conduct joint operations across its own military services inhibited its capacity for combined operations with U.S. forces. By designating a single joint commanding general, Japan is now able to coordinate more effectively with U.S. Indo-Pacific Command (USINDOPACOM) combatant commander counterparts.

In addition to growing concerns about China, Russia’s invasion of Ukraine in February 2022 caused a significant shift in the Japanese public’s perception of their country’s threat environment. The Japanese had been aware of the growing Chinese and North Korean threats, but Vladimir Putin’s invasion made clear that their perception of a “post–Cold War world” was an illusion and that large-scale military conflicts between major powers remained a genuine threat. The Russian invasion of Ukraine crystallized Japanese fears of a possible Chinese conflict over Taiwan and called attention to the need for a stronger military posture.[REF]

Before the war in Ukraine, the Japanese populace had feared that loosening any restrictions on Japan’s military risked an inexorable return to the country’s militaristic past. The war in Ukraine seemingly caused an overnight sea change in Japanese perceptions. Public opinion polls show strong majorities favoring greater defense spending and a counterstrike capability.[REF] Prime Minister Shinzo Abe’s 2015 policy of collective self-defense led to fierce debates in the national legislature and large public protests. By contrast, bold security steps announced by the Kishida administration in December 2022 elicited strong public support but did not spark any protests.

Japan responded to the deteriorating Indo-Pacific security environment by vowing to augment its defense capabilities significantly, strengthen defense cooperation with the United States, and expand defense collaboration with like-minded democracies in the Indo-Pacific. National security documents from December 2022 delineated extensive defense reforms to develop new military capabilities and bolster Japan’s ability to assume greater responsibility for its own and collective defense.[REF] In particular, Tokyo’s announcement of its intent to develop long-range missile counterstrike capabilities was a dramatic shift from the past. Citing expanding Chinese and North Korean missile arsenals, Tokyo declared that relying solely on Japanese missile defenses or U.S. strike capabilities to defend against missile threats had become increasingly untenable. The government acknowledged that it must add capabilities to mount effective counterstrikes against adversaries to prevent potential attacks on Japanese soil.

Tokyo also broke with long-standing precedent by pledging to raise Japanese defense spending by 2027 to 2 percent of current GDP, doubling the self-imposed limit of 1 percent that Tokyo had maintained for decades.[REF] The government emphasized that implementation of a rapid and extensive defense buildup could not be achieved by a temporary increase in spending. Instead, a sustained level of elevated expenditures would be required.

In recent years, Japan has taken steps to improve its defensive weapons, command, intelligence, and logistical systems:

• Integrated air and missile defenses;
• Unmanned vehicles (drones);
• Cross-domain operations including cyber, space, and electromagnetic spectrums;
• Integrated command, control, and intelligence;
• Sea-lift and air-lift capabilities;
• Expanded stocks of ammunition, missiles, fuel, and spare parts.[REF]

Japan has become increasingly alarmed by China’s surging defense expenditures, rapidly expanding and modernizing military capabilities, and escalating aerial and maritime incursions into Japanese territorial waters. Tokyo is also deeply apprehensive about being drawn into a conflict over Taiwan, which is only 70 miles from Japan’s southwest islands at their closest point. In December 2024, Foreign Minister Takeshi Iwaya noted that:

Personally, I do not like the phrase “Taiwan emergency.” Taiwan should be “safe,” not “in emergency.” Taiwan is an important and close friend to Japan. However, we will consistently adhere to the spirit of the joint statement made at the time of the normalization of diplomatic relations between Japan and China, and I am convinced that issues between Taiwan and the mainland should be resolved peacefully through dialogue. Taiwan must be “safe.”[REF]

Beginning in 2014, Japan began to reorient its forces and augment defenses to the southwest so that it could counter the Chinese threat more effectively. The Japanese Self-Defense Forces expanded existing units, created an amphibious rapid-deployment brigade, and enhanced their rapid-response capabilities. Japan also changed its strategy to improve its ability to monitor and deter Chinese incursions and, if necessary, retake islands by force. Additionally, Tokyo has deployed new radar sites, as well as surface-to-ship and surface-to-air missile units, and has increased its intelligence-gathering and security units on the islands to protect maritime choke points.

Recently, the growing potential for a Taiwan crisis has led senior Japanese officials to issue increasingly bold public statements of support for Taipei and align Japan’s national interests more directly with the protection of Taiwan’s security. However, there have been no declared policy changes, and Japan has not pledged to intervene directly in a military conflict to defend Taiwan or even to allow U.S. defense of Taiwan from bases in Japan. A Japanese decision to intervene in a Taiwan crisis would be subject to constitutional, legal, and political constraints. Deliberations would depend heavily on the circumstances of the situation and the political will to intervene. Potential factors include whether Taiwan is being attacked or blockaded, whether Japan’s southwest islands were threatened, and the extent of international support for Taiwan’s defense. However, many experts believe that Japan would be compelled to intervene militarily even without intervention by the U.S.

Republic of Korea. The United States and South Korea signed their Mutual Defense Treaty in 1953. That treaty codified the relationship that had grown from the Korean War when the United States dispatched troops to help South Korea defend itself against invasion by Communist North Korea. Since then, the two states have forged an enduring alliance supplemented by a substantial trade and economic relationship that includes a free trade agreement.[REF]

South Korea has fought alongside the United States in nearly every significant conflict since the Korean War. Seoul sent 300,000 troops to fight in Vietnam, some 5,000 of whom were killed. South Korea also has conducted anti-piracy operations off the coast of Somalia and has participated in peacekeeping operations in Afghanistan and East Timor. In spite of its support for multinational crisis response, however, South Korea’s defense planning is focused primarily on threats from North Korea. In recent years, both privately and publicly, South Korean defense officials have acknowledged the need for South Korea to expand the scope of its foreign and security policies to include threats from China.

In response to Pyongyang’s expanding nuclear arsenal, South Korea created a defense strategy comprised of Kill Chain (preemptive attack); the Korea Air and Missile Defense (KAMD) system; and the Korea Massive Punishment and Retaliation (KMPR) system.[REF] Taken together, these concepts integrate air and missile defenses, long-range precision fires, cruise missile attacks, and air-launched attacks on North Korea’s missile and nuclear capabilities and its political and military leadership.

The South Korean military is a sizeable force with advanced weapons and innovative military education and training. South Korea’s military spending has increased over the past 10 years from $36.57 billion in 2015 to $44.7 billion in 2025, and further increases are planned.[REF] Seoul also appears to be procuring the right mix of capabilities, to include long-range fires, fifth-generation aircraft, modern missile defenses, and an armor-heavy ground force.[REF] U.S.–South Korean interoperability has improved, partly as a result of Seoul’s continued purchases of U.S. weapons systems and its own healthy and modern defense industrial base.

After several decades of slow decline, the American presence on the Korean Peninsula has stabilized during the past decade. In the early 1970s, President Richard Nixon withdrew the 7th Infantry Division, leaving only the 2nd Infantry Division on the peninsula. Those forces have been positioned farther back from North Korea so that few Americans are now deployed on the Demilitarized Zone (DMZ). The U.S. currently maintains 28,500 troops on the peninsula, centered mainly on the U.S. 2nd Infantry Division, rotating brigade combat teams, and a significant number of combat aircraft.[REF]

The U.S.–ROK defense relationship involves one of the more integrated and complex command-and-control structures. A United Nations Command (UNC) established in 1950 was the basis for the American intervention and remained in place after the armistice was signed in 1953. UNC has access to seven bases in Japan to support U.N. forces in Korea. Although the 1953 armistice ended the most intense fighting, sporadic armed clashes between the two sides have continued for decades.

Due to the ongoing hostilities, UNC retained operational control (OPCON) of South Korean forces until 1978 when it was transferred to the newly established Combined Forces Command (CFC). Headed by the American Commander of U.S. Forces Korea (USFK), who is also Commander, U.N. Command, CFC reflects an unparalleled degree of U.S.–South Korean military integration. CFC returned peacetime operational control of South Korean forces to Seoul in 1994. If war became imminent, South Korean forces would become subordinate to the CFC commander, who in turn remains subordinate to both countries’ national command authorities.[REF]

In 2007, then-President Roh Moo-hyun requested that the United States return wartime OPCON of South Korean forces to Seoul.[REF] Under the plan, the CFC commander would be a South Korean general with a U.S. general as deputy commander. The U.S. general would continue to serve as commander of UNC and USFK. The CFC commander, regardless of nationality, would always remain under the direction and guidance of U.S. and South Korean political and military national command authorities.[REF] OPCON transfer has been delayed several times at Seoul’s request. Late in 2014, Washington and Seoul agreed to postpone the scheduled wartime OPCON transfer and instead adopted a conditions-based rather than timeline-based policy.[REF]

In the late 2010s, President Moon Jae-in advocated for an expedited OPCON transition during his administration, but critical conditions, including improvement in South Korean forces and a decrease in North Korea’s nuclear program, had not been met.[REF] Moon’s successor, Yoon Suk Yeol, criticized his push for a premature return of wartime OPCON before Seoul had fulfilled the agreed-upon conditions.[REF] As this book was being prepared, and almost two decades after the initial proposal, the transfer had still not been made.

The ROK’s government provides substantial resources to defray the costs of U.S. Forces Korea. The bilateral, cost-sharing Special Measures Agreement has offset the non-personnel costs of stationing U.S. forces in South Korea since 1991 and is renegotiated every five years.[REF] Korea spends 2.6 percent of its gross domestic product (GDP) on defense and has pledged to reach the NATO minimum standard of 3.5 percent in core defense spending.[REF] Seoul also absorbs costs not covered in the cost-sharing agreement, including 91 percent ($10.7 billion) of the cost of constructing Camp Humphreys, the largest U.S. base on foreign soil.[REF]

Traditionally, U.S. military forces have engaged regularly in major exercises with their ROK counterparts, including the Key Resolve and Foal Eagle series, both of which involved the deployment of substantial numbers of U.S. forces to the Korean Peninsula. Several large-scale exercises were cancelled during the first Trump Administration in 2018 but were resumed in 2022 along with the rotational deployment of U.S. strategic assets—bombers, aircraft carriers, and dual-capable aircraft.[REF] U.S. and South Korean forces concluded their annual combined, joint, all-domain military exercise, Ulchi Freedom Shield 25, in August 2025.[REF]

Japan–Korea–U.S. Trilateral Cooperation. Contentious historical issues related to Japan’s 1910–1945 occupation of the Korean Peninsula have repeatedly constrained efforts to induce the two countries to cooperate more closely on defense. South Korean–Japanese relations took a downturn in 2018 when the South Korean Supreme Court ruled that Japanese companies could be forced to pay reparations for forced labor.[REF] A December 2018 incident involving a South Korean naval ship and a Japanese air force plane further exacerbated tensions and led in turn to trade restrictions between the two countries.

To counter the growing North Korean threat, the United States, South Korea, and Japan resumed trilateral military exercises in 2022 after a five-year hiatus. The three countries engaged in anti-submarine and ballistic missile exercises to enhance security coordination. Since then, the three militaries have expanded the scope, scale, and complexity of trilateral military exercises. In March 2025, U.S., South Korean, and Japanese forces conducted a trilateral naval exercise. The joint effort was followed by another trilateral air and naval exercise, Freedom Edge, in September 2025.[REF]

Elected in March 2022, President Yoon Suk Youl took a bold and politically risky step in March 2023 to improve bilateral relations with Japan. Yoon announced that Korean rather than Japanese companies would provide compensation to Korean victims of forced labor.[REF] His decision led to the cancellation of Japanese export restrictions, progress toward enhancing economic trade, and discussion of possibly expanding military cooperation against the common North Korean threat.

During the August 2023 Camp David summit, the United States, South Korea, and Japan committed to institutionalizing trilateral security progress and creating a framework for greater cooperation against the North Korean and Chinese threats.[REF] The three countries agreed to a structured multi-year plan of annual named, large-scale, multi-domain combined military exercises near the Korean Peninsula.[REF] In 2024, the three countries activated a new mechanism for exchanging information on North Korean missile launches in real time to improve cooperation on ballistic missile defense.

During the February 2025 U.S.–Japan summit, President Donald Trump and Prime Minister Shigeru Ishiba affirmed the importance of Japan–South Korea–United States trilateral partnership against the North Korean threat.[REF] In an April 2025 meeting with his South Korean and Japanese counterparts, Secretary of State Marco Rubio pledged to “strengthen trilateral cooperation in advancing the safety, security, and prosperity of our three countries and the broader Indo-Pacific region, while upholding shared principles including the rule of law.”[REF]

The Philippines. In addition to being America’s defense ally longer than any other nation in Asia, the Philippines shares a close and complex relationship with the United States. After more than 300 years of colonial rule, Spain ceded the Philippines to the United States at the conclusion of the Spanish–American War in 1898. Over the next four decades, the United States gradually established democratic institutions and provided for increased autonomy, which culminated in full independence in 1946.

From 1941–1945, Filipinos and Americans fought side by side against the Japanese and their occupation of the Philippines. The bond forged during the war has persisted into the 21st century. Recent polls show that more than 70 percent of Filipinos view the United States favorably—a greater share than is reported by some other U.S. defense treaty allies in the Indo-Pacific.[REF]

In the wake of World War II, the U.S. and the Philippines signed a Mutual Defense Treaty in 1951 that strengthened their bilateral security ties. The Philippines was also home to some of the largest American bases in the Pacific during the Cold War. The 1947 U.S.–Philippines basing agreement allowed multiple U.S. bases in the country, the largest of which were Clark Air Base and Subic Bay Naval Base.[REF]

Subic Bay and the complex of airfields that developed around Clark Field (later Clark Air Base) provided unparalleled replenishment and repair facilities in addition to substantially extended deployment periods throughout the East Asian littoral. These bases, while controversial reminders to some Filipinos of the colonial era, generated economic activity and provided substantial lease payments to the government of the Philippines. In 1991, the United States decided to abandon Clark Air Base after it sustained significant damage from a volcanic eruption.[REF] At that time, the U.S. also offered the Philippines a reduced payment for the continued use of Subic Bay alone.[REF] The Philippines rejected the offer, thereby compelling the closure of U.S. Naval Base Subic Bay.[REF]

Despite the base closures, U.S.–Philippine military relations remained close, and assistance began to increase again after 9/11. American forces supported Philippine efforts to counter Islamic terrorist groups, including the Abu Sayyaf Group (ASG), in the south of the Philippine archipelago. From 2002–2015, the U.S. rotated 500–600 special operations forces regularly through the Philippines to assist in counterterrorism operations. That operation, Joint Special Operations Task Force–Philippines (JSOTF–P), ended during the first part of 2015.[REF]

The U.S. presence in Mindanao continued at a reduced level until the Trump Administration. Alarmed by the terrorist threat there, the U.S. began Operation Pacific Eagle–Philippines (OPE–P) in 2017. The presence of 200–300 American advisers proved valuable to the Philippines in its 2017 battle against Islamist insurgents in Marawi.[REF]

Despite a period of instability in 2020 and 2021 when then-Philippine President Rodrigo Duterte considered abrogating the 1998 U.S.–Philippines Visiting Forces Agreement, U.S.–Philippine defense ties have maintained positive momentum in recent years under the administration of President Ferdinand Marcos Jr. In April 2023, the two countries designated additional sites under the Enhanced Defense Cooperation Agreement (EDCA). The EDCA, signed in 2014, authorizes the rotational deployment of U.S. forces and prepositioning of matériel at agreed locations in the Philippines for security cooperation, joint training, and humanitarian assistance and disaster relief.[REF] The four new sites brought the total of agreed locations to nine. Two of the newly announced locations are adjacent to the South China Sea, and two are located in areas of the Philippines that are geographically near Taiwan.[REF]

America’s presence and capabilities in the Philippines have continued to deepen. In 2024, the U.S. Army deployed the Mid-Range Capability missile system, later renamed Typhon, to the Philippines for the first time.[REF] The missile batteries, capable of long-range strikes and able to engage sea and air targets, remained in the Philippines as of early 2025.[REF]

Despite a landmark 2016 United Nations Convention on the Law of the Sea (UNCLOS) arbitration ruling that China’s claims over large areas of the Philippines’ Exclusive Economic Zone (EEZ) are illegal and invalid, Chinese maritime aggression toward the Philippines in the South China Sea has escalated significantly.[REF] Filipino efforts to resupply the Sierra Madre—a deliberately grounded World War II–era naval vessel that doubles as a military outpost at Second Thomas Shoal—have faced relentless interference from the Chinese Coast Guard as part of China’s effort to intimidate Manila and erode the legitimacy of its territorial claims.[REF] These provocative measures are often carried out on gray-hull warships retrofitted for “Coast Guard” activities, continuously challenging the Philippines’ sovereignty and right to freedom of navigation in its own waters. In one particularly egregious incident in 2024, a Filipino sailor was severely injured when Chinese personnel armed with bladed weapons rammed, boarded, and attempted to scuttle Filipino vessels.[REF] In August 2025, a Chinese naval destroyer collided with a Chinese Coast Guard cutter, killing two sailors as they were harassing a Filipino vessel operating in international waters.[REF]

In recent years, the U.S. government has reiterated that any attack on the Philippines’ armed forces, including in disputed territory, would be covered under the U.S.–Philippine Mutual Defense Treaty and would trigger U.S. intervention in defense of the Philippines.[REF] In March 2025, Secretary of War Pete Hegseth reaffirmed this commitment, specifying that such an attack anywhere in the South China Sea would invoke U.S. mutual defense commitments.[REF] Emboldened by this pledge to uphold the U.S.–Philippine Mutual Defense Treaty amid rising tensions with the PRC, Philippine Defense Secretary Gilberto Teodoro cited China’s hostilities as an existential threat to his country’s stability and the region at large. His remarks followed a surge in reckless aerial maneuvers by the People’s Liberation Army Navy that buttressed his claims.[REF]

During a trip to India in August 2025, Philippine President Marcos stated that the Philippines would inevitably become involved in any conflict over Taiwan. “There is no way that the Philippines can stay out [of a war] simply because of our physical geographic location,” he told reporters. “If there is an all-out war, then we will be drawn into it.”[REF]

Thailand. The U.S.–Thai defense alliance is built on the 1954 Manila Pact, which established the now-defunct Southeast Asia Treaty Organization (SEATO), and the 1962 Thanat–Rusk agreement.[REF] These were supplemented by the Joint Vision Statements for the Thai–U.S. Defense Alliance of 2012 and 2020.[REF] In addition, Thailand gained improved access to American arms sales in 2003 when it was designated a “major, non-NATO ally.”

Thailand’s strategic location in Southeast Asia has made it an important part of America’s network of alliances in Asia. During the Vietnam War, U.S. aircraft based in Thailand ranged from fighter-bombers and B-52s to reconnaissance aircraft. In the first Gulf War and again in the Iraq War, some of those same air bases were essential for the rapid deployment of American forces to the Persian Gulf. Access to these bases remains critical to U.S. global operations.

In July 2025, recurring tensions along the Thai–Cambodian border escalated into open conflict with Cambodian rocket attacks on Thai territory resulting in Thai civilian casualties and airstrikes on Cambodian military positions using American F-16 fighter and Swedish Gripen fighter aircraft. A cease-fire was negotiated thanks to the efforts of President Trump, but significant tensions remain.[REF] Cambodia maintains close security cooperation with China, most prominently by allowing China to develop dual-use naval facilities at Ream Naval Base in Cambodia.

U.S. and Thai forces exercise together regularly. Their collaboration in the annual Cobra Gold exercises, which were initiated in 1982, builds on a partnership that began with the dispatch of Thai forces to the Korean War, during which Thailand’s approximately 12,000 troops suffered more than 1,200 casualties.[REF] Cobra Gold is the world’s longest-running international military exercise and one of its largest.[REF] A recent Cobra Gold, held from February 25 to March 7, 2025, involved more than 3,200 U.S. personnel with 30 partner nations participating either directly or as observers in the exercise.[REF] In past years, a small number of Chinese personnel also participated, but only in humanitarian assistance drills.[REF]

While U.S.–Thai security cooperation remains strong, U.S. relations with Thailand overall have been marred by persistent strain and acute crises in recent years that are idiosyncratic among U.S. treaty allies. Military coups in 2006 and 2014 limited military-to-military relations for more than a decade. This was due partly to standing U.S. law prohibiting assistance to regimes that result from coups against democratically elected governments and partly to U.S. government policy choices.

In 2017, Thailand adopted a junta-drafted constitution that institutionalized elements of military rule. Nonetheless, the United States welcomed Thailand’s first general elections under this constitution in 2019 as “positive signs for a return to a democratic government that reflects the will of the people.”[REF] Since then, bilateral military engagement has rebounded with high-level engagement and arms transfers to the Thai military of major systems like Stryker armored vehicles and Black Hawk helicopters. However, the United States denied Thailand’s requests to acquire F-35 fighter jets because of concerns that the Thai military was not capable of operating the aircraft.[REF]

Thailand is the only Southeast Asian country that was never colonized and has long pursued a hedging strategy that seeks to maintain good relations among competing powers.[REF] In the post–Cold War era, this tradition has contributed to Thailand’s geopolitical drift away from the United States and toward China—a trend that has been further encouraged by the suppression of democratic institutions in Thailand, resulting tensions in U.S.–Thai bilateral relations, China’s amenability to anti-democratic regimes, and expanding Chinese–Thai economic relations. The United States and Thailand have differing threat perceptions concerning China, and this has undermined the U.S.–Thai alliance’s clarity of purpose.

Relations between the Thai and Chinese militaries have improved steadily over the years. The two military forces have engaged in joint naval exercises since 2005, joint counterterrorism exercises since 2007, and joint marine exercises since 2010 and conducted their first joint air force exercises in 2015.[REF] The Thais conduct more bilateral military exercises with China than any other military in Southeast Asia. President Barack Obama’s sanctioning of the military junta that took power in 2014 was out of sync with historical precedent in the bilateral relationship and opened the path to this enhanced Chinese military relationship.

Thailand has purchased Chinese military equipment for many years. As of August 2025, its purchase of a Chinese diesel submarine appeared to be progressing after years of inaction; other purchases in recent years have included significant buys of battle tanks and armored personnel carriers.[REF] According to the Stockholm International Peace Research Institute (SIPRI), from 2006 to 2022, China supplied significantly more military equipment to Thailand than was supplied by the U.S.[REF]

These deals, however, have not been without difficulty. Thailand’s 2017 acquisition of Chinese submarines, for example, has been stalled first by a combination of budget restraints, the priority of COVID-19 response, and public protest and more recently by Germany’s refusal to allow export of the engines that the boats require; Thailand decided to move ahead with the purchase of Chinese submarines with Chinese engines in 2025.[REF] Submarines could be particularly critical to Sino–Thai relations because their attendant training and maintenance would require a greater Chinese military presence at Thai military facilities.

Federated States of Micronesia, Republic of the Marshall Islands, and Republic of Palau. In the South Pacific, the Federated States of Micronesia (FSM), Republic of the Marshall Islands (RMI), and Republic of Palau, known collectively as the Freely Associated States, enjoy a unique defense partnership with the United States.[REF] During World War II, these Pacific Islands were vitally important as the U.S. fought to gain a foothold in the Pacific theater in its campaign against Imperial Japan. After World War II, the Trust Territory of the Pacific Islands was administered by the United States and often used for nuclear testing; the 1954 Castle Bravo test, for example, which involved the largest U.S. bomb ever tested, was conducted at Bikini Atoll in the Marshall Islands.[REF] As the FSM, RMI, and Palau gained independence, they elected to enter a special association with the United States: the Compact of Free Association (CoFA).

About every 20 years, each of the Freely Associated States negotiates a renewal of the CoFA with the U.S. that governs its defense, economic, and immigration affairs. The CoFAs grant the U.S. control of all FAS defense matters and the power to veto any presence of third-party nations in the Compacts. The United States exclusively operates armed forces and bases throughout the FAS while being responsible for their protection, and CoFA citizens serve in the U.S. armed forces. Some restrictions apply: The United States cannot employ nuclear weapons in Palauan territory and can store them in the FSM or RMI only during war or emergency.[REF]

The United States also has the right of strategic denial. Strategic denial allows the U.S. to determine unilaterally which militaries are authorized to enter FAS territories.[REF] As China’s influence and operations throughout the Pacific Islands grow, including most recently in the Solomon Islands, the right to strategic denial becomes increasingly important.[REF]

All of the Freely Associated States have a “shiprider” agreement that allows U.S. Coast Guard (USCG) personnel and law enforcement to work with local maritime law enforcement to protect regional resources.[REF] Due to limited cutter availability, the Navy often has provided a platform for this program, which has suffered as naval warships have become less available. The USCG opened the Commander Carlton S. Skinner Building, located at USCG Forces Micronesia/Sector Guam, in 2022.[REF] In 2021, the U.S. signed an agreement to build a new military base in the FSM.[REF] The RMI hosts U.S. Army Garrison Kwajalein Atoll, the country’s second-largest employer, and the Ronald Reagan Ballistic Missile Defense Test Site.[REF]

With respect to Palau, its “[e]ligible…citizens are able to serve in the U.S. armed forces, and do so at a higher rate per capita than any U.S. state.”[REF] In 2020, Palau requested that the Pentagon build permanent military bases.[REF] It is expected that a $118 million foundational installation to support the first Tactical Mobile Over-the-Horizon Radar will be operational by 2026 with one site along the northern isthmus of Babeldaob and another on Angaur.[REF] In 2020, the 17th Field Artillery Brigade maneuvered from Guam to Palau as part of the Defense Pacific 20 exercise with a High Mobility Artillery Rocket System.[REF] In 2021, Secretary of Defense Lloyd Austin hosted Palauan President Surangel Whipps Jr. to discuss defense-related matters.[REF] In 2022, the 1st Air Defense Artillery Battalion, based out of Okinawa, held its first Patriot live-fire exercise in Palau.[REF]

Australia. Australia is one of America’s most important Indo-Pacific allies. U.S.–Australia security ties date back to World War I. They deepened during World War II when, as Japanese forces attacked the East Indies and secured Singapore, Australia turned to the United States to strengthen its defenses and American and Australian forces cooperated closely in the Pacific War. Those ties and America’s role as the main external supporter of Australian security were codified in the Australia–New Zealand–U.S. (ANZUS) pact of 1951.

Today, the two nations’ chief defense and foreign policy officials meet annually in the Australia–United States Ministerial (AUSMIN) process to address such issues of mutual concern as security developments in the Asia–Pacific region, global security and development, and bilateral security cooperation.[REF] Australia also has long granted the United States access to several joint facilities including space surveillance facilities at Pine Gap, which has been characterized as “arguably the most significant American intelligence-gathering facility outside the United States,” and naval communications facilities on the North West Cape of Australia.[REF]

In 2011, U.S. access was expanded with the U.S. Force Posture Initiatives (USFPI), which included Marine Rotational Force–Darwin and Enhanced Air Cooperation. The rotation of as many as 2,500 U.S. Marines for a set of six-month exercises near Darwin began in 2012. The current rotation is comprised of 2,500 Marines that participate in multiple live-fire and joint exercises.[REF] In the past, these forces have deployed with assets that include an MV-22 Osprey squadron, UH-1Y Venom utility and AH-1Z Viper attack helicopters, and RQ-21A Blackjack drones.

The USFPI’s Enhanced Air Cooperation component began in 2017, building on preexisting schedules of activity. New activities include “fifth generation integration, aircraft maintenance integration, aeromedical evacuation (AME) integration, refueling certification, and combined technical skills and logistics training.”[REF] Enhanced Air Cooperation has been accompanied by the buildout of related infrastructure at Australian bases including a massive fuel storage facility in Darwin.[REF] Other improvements are underway at training areas and ranges in Australia’s Northern Territories.[REF]

In 2021, the United States, Australia, and the United Kingdom, which already enjoyed close security cooperation, inaugurated a new Australia–United Kingdom–United States initiative. A key component of this partnership is support for Australia’s acquisition of “a conventionally armed, nuclear powered submarine capability at the earliest possible date, while upholding the highest non-proliferation standards.”[REF] Among other things, the partnership also focuses on improving cooperation in undersea robotic autonomous systems, long-range sensors, and hypersonic capabilities.[REF]

On March 13, 2023, the AUKUS partners announced an arrangement under which Australia will acquire nuclear submarines, to be known as SSN-AUKUS, featuring U.K. submarine design and advanced U.S. technology. The next major milestone on this “optimum pathway” will be the arrival in 2027 of the first nuclear-powered U.S. submarine to be rotationally based in HMAS Stirling.[REF]

Both Australia and the United Kingdom will deploy SSN-AUKUS, and both intend to begin domestic production before 2030. The U.K. plans to deliver its first SSN-AUKUS in the late 2030s, and Australia plans to deliver its first submarine in the early 2040s. The U.S. intends to sell three and as many as five Virginia-class submarines to Australia in the early 2030s. The agreement also includes increases in funding, training, port and personnel visits, rotations, and infrastructure projects.[REF] Although maintaining political support for the decades-long commitments may prove challenging, the envisioned pathway should unleash a new era of AUKUS partnership and security in the Indo-Pacific.

This new cutting-edge cooperation under the USFPI and AUKUS comes on top of long-standing joint U.S.–Australia training, the most prominent example of which is Talisman Saber, a series of biannual exercises that involve U.S. Army, Navy, Air Force, and Marines as well as almost two-dozen ships, multiple civilian agencies, and participants embedded from other partner countries.[REF]

In April 2023, the government of Prime Minister Anthony Albanese released what it described as “the most ambitious review of Defence’s posture and structure since the Second World War.”[REF] This Defence Strategic Review assesses that the United States is no longer the “unipolar leader of the Indo-Pacific” and recommends that Australia adopt a strategy of denial with a focused force structure that prioritizes the “most significant military risks.”[REF] China’s strategic intentions, demonstrated by its military buildups and provocative actions in the South China Sea and Pacific Islands, are assessed as likely to have a negative impact on Australian interests.[REF] The Albanese government either agreed or agreed in principle to adopt or implement all of the review’s 62 recommendations.[REF]

In early August 2024, the United States and Australia announced plans to increase the rotational presence of U.S. forces in Australia by boosting maritime patrol, reconnaissance, and bomber aircraft capabilities.[REF] At the same time, Australia signed a defense cooperation agreement with Indonesia to tighten intermilitary coordination and joint exercises.[REF] Australia’s precision-strike capabilities and industrial-operational linkage with the United States were further bolstered early in 2025 by progress on a joint endeavor to co-manufacture Guided Multiple Launch Rocket Systems (GMLRS).[REF] In addition, existing mineral refining facilities in Henderson, Australia, are being upgraded with Japanese investment to process rare earth minerals, mitigating the death grip China currently holds over the world in processing these critically important minerals for high-tech weaponry.

Singapore. The island state of Singapore is arguably America’s closest non-ally partner in the Western Pacific. The agreements that support this security relationship are the 2015 U.S.–Singapore Enhanced Defense Cooperation Agreement (DCA), an update of a similar 2005 agreement, and the 1990 Memorandum of Understanding Regarding United States Use of Facilities in Singapore, which was renewed in 2019 for another 15 years.[REF] The city-state also has ongoing defense ties to China and conducted a bilateral maritime drill in the South China Sea in May 2025.[REF]

Pursuant to these agreements and other understandings, Singapore hosts U.S. naval ships and aircraft as well as Logistics Group Western Pacific, principal logistics command unit for the U.S. Seventh Fleet.[REF] U.S. Navy P-8 Poseidon maritime patrol aircraft began rotational deployments to Singapore in 2015, and Littoral Combat Ships have deployed to Singapore since 2016.[REF] The U.S. Air Force began rotational deployments of RQ-4 Global Hawk unmanned aircraft to Singapore in 2023.[REF] Notably, the Changi Naval Base is capable of hosting U.S. aircraft carriers, which visit regularly; the USS Carl Vinson conducted the most recent port call in June 2025 .[REF]

According to the U.S. Department of State, “[t]he United States has $8.38 billion in active government-to-government sales cases with Singapore under the Foreign Military Sales (FMS) system” and “[f]rom 2019 through 2021…authorized the permanent export of over $26.3 billion in defense articles to Singapore via Direct Commercial Sales (DCS).”[REF] In addition, “more than 1,000 Singaporean military personnel participate in training, exercises, and Professional Military Education in the United States,” and “Singapore has operated advanced fighter jet detachments in the continental United States for 27 years.”[REF]

In January 2020, it was announced that Singapore had been “formally approved to become the next customer of the F-35 Joint Strike Fighter, paving the way for a future sale.”[REF] Like others of its assets, the four F-35s were to be housed at training facilities in the U.S. and perhaps on Guam under an agreement reached in 2019.[REF] In February 2024, it was reported that “Singapore’s Defence Ministry plans to order eight more F-35A jets, which would bring the country’s Joint Strike Fighter fleet to 20.”[REF]

New Zealand. New Zealand has been a U.S. ally since the 1951 ANZUS treaty. For much of the Cold War, U.S. defense ties with New Zealand were similar to those between America and Australia. In 1986, New Zealand was suspended from the ANZUS treaty for pursuing a “nuclear free zone” and barring nuclear-powered vessels from entering its 12-nautical-mile territorial sea.[REF] The Kiwi government has become increasingly concerned about Chinese influence in the region, and the country’s spy chief issued a warning about this influence in March 2025.[REF] In February 2025, Wellington was shocked when Cook Islands, which New Zealand provides with security and financial support through a free association agreement, concluded a wide-reaching deal with China.[REF]

Defense relations improved in the early 21st century as New Zealand committed forces to Afghanistan and dispatched an engineering detachment to assist the United States during the Iraq War. The 2010 Wellington Declaration and 2012 Washington Declaration, while not restoring full security ties, allowed the two nations to resume high-level defense dialogues.[REF] As part of this warming of relations, New Zealand rejoined the multinational U.S.-led RIMPAC (Rim of the Pacific) naval exercise in 2012 and has participated in each iteration since then.

In 2013, Washington and Wellington announced the resumption of military-to-military cooperation, and in July 2016, the United States accepted an invitation from New Zealand to make a single port call, reportedly with no change in U.S. policy to confirm or deny the presence of nuclear weapons on the ship.[REF] At the time of the visit in November 2016, both sides claimed to have satisfied their respective legal requirements.[REF] Prime Minister John Key expressed confidence that the vessel was not nuclear-powered and did not possess nuclear armaments; the U.S. neither confirmed nor denied this.

The November 2016 visit occurred in a unique context, including an international naval review and a relief response to the Kaikoura earthquake. Since then, there have been several other visits by U.S. Coast Guard vessels. In 2017, New Zealand lent one of its naval frigates to the U.S. Seventh Fleet following a deadly collision between the destroyer USS Fitzgerald and a Philippine container ship that killed seven American sailors.[REF] In November 2021, the guided-missile destroyer USS Howard made a port call in New Zealand.[REF]

In April and May 2024, a New Zealand Royal P-8A Poseidon conducted 11 missions to detect and deter evasions of United Nations Security Council resolutions with a particular focus on North Korea’s testing of ballistic missiles.[REF] In mid-summer 2024, the Royal New Zealand Navy maritime sustainment vessel arrived in Pearl Harbor to participate in RIMPAC 24.[REF]

Prime Minister Christopher Luxon, elected in 2023, has ushered in a new era of responsible national security policy for New Zealand in a notable departure from the China-friendly policies of his predecessor, Jacinda Ardern. Luxon declared in a speech in August 2024 that New Zealand “can’t achieve prosperity without security” and would need to increase its defense spending and work with other militaries in the region, especially traditional partners like Australia, Britain, NATO, and the United States.[REF]

New Zealand is a member of the Five Eyes intelligence alliance with the U.S., Canada, Australia, and the United Kingdom[REF] After a period of record attrition in the New Zealand Defence Force that led to the idling of three naval vessels and early retirement of the country’s P-3 Orion fleet, New Zealand is reportedly considering “the possibility of…becoming a non-nuclear partner of AUKUS” and increasing overall resources allocated to defense.[REF] Luxon’s 2025 Defense Capability Plan aims to increase New Zealand’s defense spending to 2 percent of GDP over the next eight years with significant investments in increased strike capabilities in recognition of the fact that New Zealand faces “its most challenging and dangerous strategic environment [in] decades.”[REF]

Taiwan. When the United States shifted its recognition of the government of China from the Republic of China (Taiwan) to the People’s Republic of China (PRC) in 1979, it also declared certain commitments to Taiwan’s security. These commitments are embodied in the Taiwan Relations Act (TRA) and the subsequent “Six Assurances.”[REF] In a critical move, key documents declassified late in the first Trump Administration further specified that sustained provision of weapons to Taiwan will be a function of China’s threat to take military action.[REF]

The TRA is an American law, not a treaty. Under the TRA, the United States maintains programs, transactions, and other relations with Taiwan through the American Institute in Taiwan (AIT). Except for the Sino–U.S. Mutual Defense Treaty, which had governed U.S. security relations with Taiwan and was terminated by President Jimmy Carter following the shift in recognition to the PRC, all other treaties and international agreements made between the Republic of China and the United States remain in force.

The TRA requires the United States “to provide Taiwan with arms of a defensive character.”[REF] It also states that the U.S. “will make available to Taiwan such defense articles and services in such quantity as may be necessary to enable Taiwan to maintain a sufficient self-defense capability.”[REF] The U.S. has implemented these provisions of the act through sales of weapons to Taiwan.

The TRA states that it is also U.S. policy both “to consider any effort to determine the future of Taiwan by other than peaceful means, including by boycotts or embargoes, a threat to the peace and security of the Western Pacific area and of grave concern to the United States” and “to maintain the capacity of the United States to resist any resort to force or other forms of coercion that would jeopardize the security, or the social or economic system, of the people on Taiwan.”[REF] To this end:

The President is directed to inform the Congress promptly of any threat to the security or the social or economic system of the people on Taiwan and any danger to the interests of the United States arising therefrom. The President and the Congress shall determine, in accordance with constitutional processes, appropriate action by the United States in response to any such danger.[REF]

Supplementing the TRA are the “Six Assurances” issued by President Ronald Reagan in a secret July 1982 memo and later publicly released and the subject of hearings held by the Senate Committee on Foreign Relations and the House Committee on Foreign Affairs in August 1982.[REF] These assurances, which were intended to moderate the third Sino–American communiqué, itself generally seen as one of the “Three Communiqués” that form the foundation of U.S.–PRC relations, specified that:

In negotiating the third Joint Communiqué with the PRC, the United States:

1. has not agreed to set a date for ending arms sales to Taiwan;
2. has not agreed to hold prior consultations with the PRC on arms sales to Taiwan;
3. will not play any mediation role between Taipei and Beijing;
4. has not agreed to revise the Taiwan Relations Act;
5. has not altered its position regarding sovereignty over Taiwan;
6. will not exert pressure on Taiwan to negotiate with the PRC.[REF]

Although the United States sells Taiwan a variety of military equipment, provides limited training to Taiwanese military personnel, and sends observers to Taiwan’s major annual exercises, it does not engage in joint exercises with Taiwan’s armed forces. Some Taiwan military officers attend professional military education institutions in the United States, and there are regular high-level meetings between senior U.S. and Taiwan defense officials, both uniformed and civilian.

The United States does not maintain any military bases on Taiwan. However, in late 2021, after reports of an uptick in the number of U.S. military advisers in Taiwan, President Tsai Ing-wen acknowledged that they had been present at least since 2008.[REF] In April 2024, a U.S. congressional report put the number of these advisers at 41, but media reports indicate that there could be as many as 200.[REF] Most will continue to focus on training Taiwanese soldiers to use U.S.-sourced military equipment and to carry out military maneuvers with a view to defending Taiwan against a hypothetical attack by China.

In October 2024, the United States approved a $2 billion arms sale to Taiwan that featured the delivery of three National Advanced Surface-to-Air Missile Systems (NASAMS) along with radar systems valued at $828 million.[REF] As announced by the Pentagon’s Defense Security Cooperation Agency, the sale also included coveted Advanced AMRAAM Extended Range surface-to-air missiles. In December 2025, the Trump Administration announced an $11.1 billion arms sale package to Taiwan that included HIMARS rocket systems, howitzers, Javelin anti-tank missiles, and drones.

In 2024 and 2025, China continued to intensify its military activities around the island nation with the People’s Liberation Army Air Force (PLAAF) and People’s Liberation Army Navy (PLAN) constantly testing Taiwan’s detection and defenses. The October 2024 Joint Sword 2024B exercise deployed 111 PLAAF aircraft that engaged in daily incursions into Taiwanese airspace and a nearly constant naval presence.[REF] These gray-zone tactics make clear China’s intent to desensitize the world to its constant military presence around the island and prepare for real-world combat scenarios. Taiwan responded to this increased aggression by announcing a 7.7 percent increase in its 2024 defense budget to roughly $19 billion and approximately 2.5 percent of GDP.[REF]

President Lai Ching-te announced major defense increases in 2025 with Taiwan set to reach 3.32 percent of GDP by 2026 and 5 percent of GDP by 2030. President Lai announced the 5 percent increase in a speech at a Taiwanese naval base, stating that the increase “not only demonstrates our country’s determination to safeguard national security and protect democracy, freedom and human rights,” but also “shows our willingness to stand shoulder-to-shoulder with the international community to jointly exert deterrent power and maintain peace and stability in the Indo-Pacific region.”[REF]

Vietnam, Malaysia, and Indonesia. In Southeast Asia, the U.S. has two major ongoing defense-related initiatives to expand its relationships and diversify the geographical spread of its forces:

• The Maritime Security Initiative, which is intended to improve the security capacity of U.S. partners, and
• The Pacific Deterrence Initiative (PDI), which bolsters America’s military presence and makes it more accountable.

Among the most important of the bilateral partnerships in this effort are those with Vietnam, Malaysia, and Indonesia. None of these relationships is as extensive and formal as America’s relationship with Singapore, India, and U.S. treaty allies, but all are of growing significance.

Vietnam. After decades without diplomatic relations following the Vietnam War, improved bilateral relations in recent years have led to Vietnam’s emergence as a nascent U.S. security partner. Relations have been strengthened by U.S. efforts to assist Vietnam in mitigating continued dangers from Vietnam War–era unexploded ordnance (UXO) as well as bilateral efforts to address other war-related issues. Since 1993, for example, “the U.S. government [has] contributed more than $230 million for UXO efforts,” and “UXO assistance continues to be a foundational element of U.S.–Vietnam relations.”[REF]

Diplomatic relations between the United States and Vietnam were normalized in 1995. Since then, the two countries also have gradually improved their defense relationship, codified in 2011 with a Memorandum of Understanding (MOU) Advancing Bilateral Defense Cooperation.[REF] In 2015, the MOU was updated by the Joint Vision Statement on Defense Cooperation, which includes references to such issues as “defense technology exchange” and was implemented under a three-year 2018–2020 Plan of Action for United States–Viet Nam Defense Cooperation that was agreed upon in 2017.[REF]

In 2022, the two sides updated their defense MOU, and in 2023, they upgraded the bilateral relationship to a Comprehensive Strategic Partnership that provides an “overarching framework” for relations that “have become increasingly cooperative and comprehensive, evolving into a flourishing partnership that spans political, economic, security, and people-to-people ties.”[REF] Nevertheless, significant limits on the U.S.–Vietnam security relationship persist, including a Vietnamese defense establishment that is very cautious in its selection of defense partners; ties between the Communist Party of Vietnam (CPV) and the Chinese Communist Party (CCP); and a Vietnamese foreign policy that seeks to balance relationships with all major powers.

The most significant development with respect to security ties over the past several years has been relaxation of the U.S. ban on sales of arms to Vietnam. The U.S. lifted the embargo on maritime security–related equipment in the fall of 2014 and then ended the embargo on arms sales completely in 2016. The embargo had long served as a psychological obstacle to Vietnamese cooperation on security issues, but lifting it has not changed the nature of the articles that are likely to be sold.

Most transfers have been to the Vietnamese Coast Guard and include provision under the Excess Defense Articles (EDA) program of three decommissioned Hamilton-class cutters and 24 Metal Shark patrol boats as well as infrastructure support.[REF] Vietnam is scheduled to take delivery of six Insitu ScanEagle unmanned aerial system (UAS) drones for its Coast Guard.[REF] The U.S. is also providing T-6 turboprop trainer aircraft.[REF] Agreement has yet to be reached with respect to sales of bigger-ticket items like refurbished P-3 maritime patrol aircraft, but they have been discussed.

The U.S.–Vietnam Cooperative Humanitarian and Medical Storage Initiative (CHAMSI) is designed to enhance cooperation on humanitarian assistance and disaster relief by, among other things, prepositioning related American equipment in Da Nang, Vietnam.[REF] This is a sensitive issue for Vietnam and is not often referenced publicly, but it was emphasized during Vietnamese Prime Minister Nguyen Xuan Phuc’s visit to Washington in 2017 and again during Secretary of Defense James Mattis’s visit to Vietnam in 2018. In the same year, Vietnam participated in RIMPAC for the first time.

There have been three high-profile port calls to Vietnam since 2018. Early that year, the USS Carl Vinson and its escort ships visited Da Nang in the first port call by a U.S. aircraft carrier since the Vietnam War.[REF] Another carrier, USS Theodore Roosevelt, visited Da Nang in March 2020, and the USS Ronald Reagan and two guided-missile cruiser escorts visited Da Nang in 2023.[REF] These are significant signals from Vietnam about its receptivity to partnership with the U.S. military—messages underscored very subtly in Vietnam’s 2019 Viet Nam National Defence white paper.[REF] The U.S., like others among Vietnam’s security partners, remains officially restricted to one port call a year with an additional one to two calls on Vietnamese bases being negotiable.

Vietnam maintains close ties to China, especially economically, but China’s nine-dash line claims against Vietnamese-claimed features in the South China Sea are a consistent source of dispute that have boiled over in the past. In 2014, a state-owned Chinese oil company placed a deep-sea drilling rig in disputed waters and dispatched 80 ships (including seven military vessels) to support the rig. When Vietnam sent ships to disrupt the operation, China turned water cannons on the Vietnamese ships and rammed several of them, leaving Vietnamese sailors injured and damaging the vessels.[REF] The incident caused anti-Chinese riots in Vietnam.[REF]

Malaysia. The United States and Malaysia, despite occasional political differences, “have maintained steady defense cooperation since the 1990s.” Examples of this cooperation have included Malaysian assistance in the reconstruction of Afghanistan and involvement in antipiracy operations “near the Malacca Strait and, as part of the international anti-piracy coalition, off the Horn of Africa” as well as “jungle warfare training at a Malaysian facility, bilateral exercises like Kris Strike, and multilateral exercises like Cobra Gold, which is held in Thailand and involves thousands of personnel from several Asian countries plus the United States.”[REF] The U.S. has occasionally flown P-3 and/or P-8 patrol aircraft out of Malaysian bases in Borneo.

In addition to cooperation on counterterrorism, the United States is focused on helping Malaysia to ensure maritime domain awareness. In 2020, then-Deputy Assistant Secretary of Defense for South and Southeast Asia Reed B. Werner summarized recent U.S. assistance in this area:

[M]aritime domain awareness is important for Malaysia, given where it sits geographically. Since 2017, we have provided nearly US$200 million (RM853 million) in grant assistance to the Malaysian Armed Forces to enhance maritime domain awareness, and that includes ScanEagle unmanned aerial vehicles (UAV), maritime surveillance upgrades, and long-range air defence radar.[REF]

Malaysia has also been upgrading its fleet of fighter aircraft. In February 2023, Malaysia awarded a $920 million contract to Korea Aerospace Industries for 18 FA-50 light attack aircraft, the first of which is to be delivered in 2026.[REF]

South China Sea territorial disputes continue to strain diplomatic ties between China and Malaysia. China’s “2023 Standard Map,” which Malaysia and other regional parties rejected, shows claims to the Luconia Shoals, which Malaysia considers to be part of its EEZ.[REF] Chinese Coast Guard incursions near Malaysian oil and gas operations have likewise fomented consternation in Kuala Lumpur. Tensions were particularly elevated during a 2020 maritime incident involving a standoff with the Petronas-contracted West Capella vessel.[REF] By early 2024, increased Chinese activity at Luconia Shoals had prompted the deployment of additional Malaysian naval resources.[REF]

Malaysia has improved security relations with the United States and Japan in recent years partly because of concerns about China’s designs on the South China Sea. In April 2024, Malaysia and Japan conducted joint drills in the South China Sea that featured the Japan Maritime Self-Defense Force.[REF] Nevertheless, China and Malaysia signed a five-year trade agreement during a June 2024 visit by Chinese Premier Li Qiang.[REF]

Indonesia. The U.S.–Indonesia defense relationship was revived in 2005 following a period of estrangement caused by American concerns about the Indonesian government’s violations of human rights. It now includes regular joint exercises, port calls, and sales of weaponry. Because of their impact on the operating environment in and around Indonesia, as well as the setting of priorities in the U.S.–Indonesia relationship, the United States has also worked closely with Indonesia’s defense establishment to reform Indonesia’s strategic defense planning processes.

Indonesia has an active territorial dispute with China in the South China Sea, particularly around the Natuna Islands.[REF] Tensions have grown over the past several years as a result of repeated incursions by Chinese fishing vessels and coast guard ships into Indonesian waters. In October 2024, Indonesian patrol ships expelled a Chinese coast guard ship that had disrupted a survey by an Indonesian state-owned energy company.[REF] As a result, Indonesian military modernization has accelerated along with long-standing and long-stalled ASEAN efforts to negotiate a code of conduct for the South China Sea with China.[REF]

Indonesia’s traditional policy of balancing alignment among multiple powers continues under President Prabowo Subianto, who assumed office in October 2024. In November 2024, true to its “free and active” foreign policy doctrine, Indonesia held its first bilateral naval exercise with Russia, Orruda 2024, in the Java Sea near Surabaya. The exercise involved four Russian warships and included a submarine visit.[REF]

U.S.–Indonesia military cooperation is governed by the 2010 Framework Arrangement on Cooperative Activities in the Field of Defense, the 2015 Joint Statement on Comprehensive Defense Cooperation, and the 2010 Comprehensive Partnership.[REF] These agreements have encompassed “more than 200 bilateral military engagements a year” and cooperation in six areas: “maritime security and domain awareness; defense procurement and joint research and development; peacekeeping operations and training; professionalization; HA/DR [Humanitarian Assistance/Disaster Relief]; and countering transnational threats such as terrorism and piracy.”[REF]

In 2021, the agreements framed new progress in the relationship that included breaking ground on a new coast guard training base, inauguration of a new Strategic Dialogue, and the largest-ever U.S.–Indonesia army exercise.[REF] In 2022, this exercise, Garuda Shield, involved “more than 4,000 combined forces from 14 countries.”[REF] As of January 2025, the U.S. “ha[d] $1.88 billion in active government-to-government sales cases with Indonesia under the Foreign Military Sales (FMS) system.”[REF] In February 2022, the U.S. agreed to sell Indonesia “up to 36” F-15s and related equipment and munitions worth $14 billion.[REF] In 2024, it was reported that Indonesia had negotiated an agreement with Boeing to purchase 24 F-15EX jets.[REF] In June 2024, the U.S. and Indonesia conducted Exercise Cooperation Afloat Readiness Training (CARAT) Indonesia, marking the 30th iteration of the exercise and commemorating 75 years of diplomatic relations.[REF]

The United States and Indonesia also have signed two of the four foundational information-sharing agreements that the U.S. maintains with its closest partners: the General Security of Military Information Agreement (GSOMIA) and Communications Interoperability and Security Memorandum of Agreement (CISMOA).

Afghanistan. On October 7, 2001, U.S. forces invaded Afghanistan in response to the September 11, 2001, terrorist attacks on the United States. This was the beginning of Operation Enduring Freedom to combat al-Qaeda and its Taliban supporters. The U.S., in alliance with the U.K. and anti-Taliban Afghan Northern Alliance forces, ousted the Taliban from power in December 2001. Most Taliban and al-Qaeda leaders fled across the border into Pakistan’s Federally Administered Tribal Areas where they regrouped and in 2003 initiated an insurgency in Afghanistan that would endure for 20 years.

In 2018, U.S. Special Envoy Zalmay Khalilzad initiated talks with the Taliban in Doha, Qatar, in an attempt to find a political solution to the conflict and encourage the group to negotiate with the Afghan government.[REF] In April 2021, remarking that America’s “reasons for remaining in Afghanistan are becoming increasingly unclear,” President Joseph Biden announced that the U.S. would be withdrawing its remaining 2,500 soldiers by September 11, 2021.[REF]

As the final contingent of U.S. forces was leaving Afghanistan in August 2021, the Taliban launched a rapid offensive across the country, seizing provincial capitals and eventually the national capital, Kabul, in a matter of weeks. During the Taliban offensive, Afghan President Ashraf Ghani fled the country for the United Arab Emirates (UAE), and the Afghan National Defense and Security Forces (ANDSF) largely abandoned their posts.[REF] Amid the chaos, a suicide bombing attack on the airport perimeter on August 26 killed 13 U.S. military personnel and nearly 200 Afghans. Islamic State of Iraq and ash-Sham–Khorasan (ISIS-K), the local branch of ISIS, claimed responsibility for the attack, and the Biden Administration subsequently launched drone strikes on two ISIS-K targets.[REF]

The last U.S. forces were withdrawn on August 30, 2021, and the Taliban soon formed a new government comprised almost entirely of hard-line elements of the Taliban and Haqqani Network, including several individuals on the U.S. government’s Specially Designated Global Terrorists list.[REF] Since seizing power, the Taliban government has hunted down and executed hundreds of former government officials and members of the ANDSF. It also has cracked down on Afghanistan’s free press, banned education for girls beyond sixth grade while the daughters of several Taliban leaders attend school in Pakistan and the UAE, and curtailed the rights of women and minorities. Under Taliban rule, the Afghan economy has collapsed.

The United States and most other countries have refused to offer the new Taliban government diplomatic recognition. Analysts believe al-Qaeda and ISIS-K are still operating in Afghanistan and intend to conduct terrorist attacks abroad, including attacks against the U.S.[REF] In August 2022, a U.S. drone strike killed al-Qaeda leader Ayman al Zawahari, who was discovered residing in a safehouse in Kabul.[REF] The U.S. government claimed the Taliban had violated its agreement with the U.S., reached at Doha, in which it pledged not to host al-Qaeda and other international terrorist groups.[REF]

Most ambassadors still stay away from Kabul, but the same cannot be said for Russia and China. In July 2025, Russia became the first country to recognize the Taliban government, giving rise to discussions about potential joint investment projects.[REF] In 2024, CCP General Secretary Xi Jinping accepted the Taliban ambassador’s credentials, and in 2025, China’s foreign minister visited the country to discuss whether Kabul might possibly join the Belt and Road Initiative (BRI).[REF]

The Taliban–Haqqani government has been the target of attacks, violence, and assassinations from ISIS-K. The Islamist extremist group has been competing with the Taliban–Haqqani Network alliance for territory and recruits ever since its emergence in 2015. Meanwhile, the Pakistani Taliban, allies of the Afghan Taliban and Haqqani Network, have escalated attacks against neighboring Pakistan since the withdrawal of U.S. forces from Afghanistan, straining relations between Islamabad and Kabul. In late 2024 and early 2025, the Taliban government itself became divided by a sharpening rift between the Haqqani Network and the Afghan Taliban leadership based in Kandahar.[REF]

Pakistan. After decades of tactical collaboration during the Cold War, Pakistan and the United States developed an often troubled relationship after the U.S. invasion of Afghanistan in 2001. During the early stages of the war, the U.S. and NATO relied heavily on logistical supply lines running through Pakistan to resupply anti-Taliban coalition forces. For roughly the first decade of the war, approximately 80 percent of U.S. and NATO supplies traveled through Pakistani territory. Those amounts decreased progressively as the U.S. and allied troop presence decreased.

In the late 2000s, tensions emerged in the relationship when the United States alleged that Pakistan was providing a safe haven to the Taliban and its allies as they intensified their insurgency in Afghanistan. The Taliban’s leadership council was located in Quetta, the capital of Pakistan’s Baluchistan province. U.S.–Pakistan relations suffered an acrimonious rupture in 2011 when U.S. special forces conducted a raid on Osama bin Laden’s hideout in Abbottabad less than a mile from a prominent Pakistani military academy.[REF]

Since 2015, U.S. Administrations have refused to certify that Pakistan has met requirements to crack down on the Haqqani Network, an Afghan terrorist group with known links to Pakistan’s Inter-Services Intelligence Agency.[REF] Relations deteriorated further in 2017 when President Trump suspended billions of dollars of U.S. military assistance to Pakistan and declared that “[w]e can no longer be silent about Pakistan’s safe havens for terrorist organizations, the Taliban, and other groups that pose a threat to the region and beyond.”[REF]

Despite harboring and supporting a variety of known terrorist groups that operate in Afghanistan and Kashmir, Pakistan has been subject to terrorism from anti-state extremist groups, including the Pakistani Taliban (TTP). In the late 2000s and early 2010s, the TTP engaged in a bloody campaign of terrorism against the Pakistani state; from 2008–2013, approximately 2,000 civilians were killed in terrorist attacks each year. The Pakistan military launched a series of operations against these groups in 2014 and succeeded in progressively reducing terrorist violence in the years that followed.[REF]

However, after the Afghan Taliban assumed power in Kabul, the number of attacks on Pakistan civilian and military targets spiked dramatically.[REF] Islamabad has repeatedly accused the Taliban government in Kabul of harboring the TTP and ISIS-K—the two groups that took credit for most of these attacks—or failing to rein in their activities. Tensions reached a tipping point in April 2022 when the Taliban accused Pakistan of launching cross-border raids into Afghanistan to target these groups and causing dozens of civilian casualties in the process.[REF]

The Pakistani government’s peace negotiations with the TTP have produced a cycle of temporary cease-fires punctuated by cycles of violence and terrorism against civilians and Pakistani security personnel. Pakistan claims that the Taliban-led government in Kabul is either collaborating with the Pakistani Taliban or tacitly permitting them to use Afghan soil to launch attacks inside Pakistan. “With Taliban acquiescence, and at times support, TTP has intensified attacks inside Pakistan,” a U.N. Security Council Committee reported in 2024, including attacks on Chinese nationals that have strained ties between Islamabad and Beijing.[REF]

Pakistan–U.S. relations improved modestly from 2018–2021 as Pakistan involved itself in bringing the Afghan Taliban to the negotiating table in Doha, but they have been notably strained since the U.S. withdrawal from Afghanistan. President Biden reportedly refused to engage in direct communications with his Pakistani counterpart, and Deputy Secretary of State Wendy Sherman visited Pakistan in October 2021 to discuss “the importance of holding the Taliban accountable to the commitments they have made.” Days earlier, she noted that “[w]e don’t see ourselves building a broad relationship with Pakistan. And we have no interest in returning to the days of hyphenated India–Pakistan.”[REF]

In a shocking revelation in December 2024, a senior White House official said that Pakistan was developing intercontinental ballistic missile capabilities that would allow it to “strike targets well beyond South Asia, including the United States.”[REF] Given that Pakistan’s only real geopolitical rival—India—is already covered by its short-range and medium-range arsenal, Deputy National Security Adviser Jon Finer admitted that “it’s hard for us to see Pakistan’s actions as anything other than an emerging threat to the United States.”[REF] The revelation was paired with the announcement of unprecedented new sanctions on Pakistan’s state-run ballistic missile program.[REF]

In addition to a deteriorating security situation and relationship with the United States, Pakistan has been subject to paralyzing economic and political crises in recent years. Prime Minister Imran Khan was ousted from power in April 2022 after losing a no-confidence vote in parliament and was later barred from running for office for five years based on charges that he insists are politically motivated. Khan’s arrest on corruption charges in May 2023 was followed by widespread protests.[REF] However, by month’s end, Khan was released, the protests abated, and several members of his political party defected.[REF] He was arrested again in August 2023 on corruption charges and since then has remained in prison facing charges in over 100 court cases.

In 2024, Khan was sentenced to 24 years in prison for selling state gifts and leaking state secrets. Those sentences were suspended months later, but in January 2025, Khan was sentenced to 14 years in prison in a separate corruption case.[REF] Former Prime Minister Shahbaz Sharif cobbled together a patchwork coalition to govern the country following national elections in February 2024.

Pakistan has pursued relations with China over the past decade. The South Asian nation is one of the top recipients of Chinese BRI investment, including investment in the port of Gwadar, which could serve Chinese naval vessels.[REF] Pakistan has also received substantial security assistance from China; according to one estimate, as much as 80 percent of Pakistan’s weaponry used during the 2025 India–Pakistan War came from China.[REF]

Pakistan’s economy is teetering on the verge of collapse with skyrocketing inflation, dwindling foreign exchange reserves, and a growing and unsustainable mountain of government debt. These problems were made even worse by devastating floods in 2022 that killed thousands and affected millions. The Pakistani government is seeking billions of dollars in aid simply to meet its growing debt obligations but has found multilateral lenders like the International Monetary Fund and traditional patrons like Saudi Arabia and China increasingly unwilling to provide relief on favorable terms.

Pakistan’s Nuclear Weapons Stockpile. In September 2021, the Bulletin of the Atomic Scientists estimated that Pakistan “now has a nuclear weapons stockpile of approximately 165 warheads.” The report added that “[w]ith several new delivery systems in development, four plutonium production reactors, and an expanding uranium enrichment infrastructure, however, Pakistan’s stockpile…could grow.”[REF] It is therefore highly possible that approximately 200 warheads could be in Pakistan’s arsenal by the end of 2025.

The possibility that terrorists could gain effective access to Pakistani nuclear weapons is contingent on a complex chain of circumstances. Concern about the safety and security of Pakistan’s nuclear weapons increases when India–Pakistan tensions increase. If Pakistan were to move its nuclear assets or (worse) take steps to mate weapons with delivery systems, the likelihood of theft or infiltration by terrorists could well increase.

Increased reliance on non-strategic nuclear weapons is of particular concern because launch authorities for such weapons are typically delegated to lower-tier field commanders far from the central authority in Islamabad. This could give these commanders the ability to launch nuclear weapons on their own authority in times of acute crisis or conflict. Another concern is that miscalculations could lead to regional nuclear war if India’s leaders were to lose confidence that nuclear weapons in Pakistan are under government control or were to assume that they were under Pakistani government control after they had ceased to be. In this sense, either side could trigger a preemptive or surprise nuclear strike on the other with little to no tactical warning.

There are additional concerns that Islamist extremist groups with links to the Pakistan security establishment could exploit those links to gain access to nuclear weapons technology, facilities, and/or materials. The realization that Osama bin Laden stayed for six years within a mile of Pakistan’s premier defense academy has fueled concern that al-Qaeda can operate relatively freely in parts of Pakistan. The Nuclear Threat Initiative (NTI) ranked Pakistan’s weapons-grade materials as 19th least secure in 2023 with only Iran’s and North Korea’s ranked as less secure at 21st and 22nd, respectively.[REF] In its 2020 report, the NTI assessed that the “[m]ost improved among countries with materials in 2020 is Pakistan, which was credited with adopting new on-site physical protection and cybersecurity regulations, improving insider threat prevention measures, and more.”[REF] In 2023, however, it reported that “[e]ight countries—France, India, Iran, Israel, North Korea, Pakistan, Russia, and the United Kingdom—have increased their stocks of weapons-usable nuclear materials, in some cases by thousands of kilograms per year, undermining minimization and elimination efforts and increasing the risk of theft.”[REF]

There is the additional (though less likely) scenario of extremists gaining access as the state collapses. Although Pakistan remains unstable because of its weak economy, regular terrorist attacks, sectarian violence, civil–military tensions, and the growing influence of religious extremist groups, a total collapse of the Pakistani state is highly improbable. The country’s most powerful institution, the 550,000-strong army that has ruled for almost half of Pakistan’s existence, would almost certainly intervene and reassume control if the political situation began to unravel. The potential breakup of the Pakistani state would have to be preceded by the disintegration of the army, which currently is not likely to happen.

Pakistan–India Conflict. India and Pakistan have fought four wars since partition in 1947, including conflicts in 1947, 1965, 1971, and 1999. Deadly border skirmishes across the Line of Control (LoC) in Kashmir, a disputed territory claimed in full by both India and Pakistan, are common occurrences.

With terrorist groups operating relatively freely in Pakistan and maintaining links to its military and intelligence services, there is a moderate risk that the two countries might eventually engage in another conflict. Pakistan’s recent focus on incorporating tactical nuclear weapons into its warfighting doctrine has also raised concern that conflict now involves a higher risk of nuclear exchange. Early in 2019, Pakistan conducted several tests of its nuclear-capable, short-range NASR ballistic missiles.[REF]

On December 25, 2015, Indian Prime Minister Narendra Modi made an impromptu visit to Lahore—the first visit to Pakistan by an Indian leader in 12 years—to meet with Prime Minister Nawaz Sharif. The visit created goodwill between the two countries and raised hope that official dialogue would soon resume. As happened frequently in the past, however, violence marred and undermined the diplomatic opening. One week after the meeting, terrorists attacked an Indian airbase at Pathankot, killing seven Indian security personnel.[REF] Ever since then, a comprehensive India–Pakistan dialogue has remained frozen, although the two governments still communicate regularly through various channels.

Despite New Delhi’s insistence that Pakistan take concrete, verifiable steps to crack down on terrorist groups before a comprehensive dialogue covering all outstanding issues—including the Kashmir dispute—can resume, the past few years have been marred by occasional terrorist attacks and cross-border shelling. In addition to the January 2016 attack on the Indian airbase at Pathankot, the Pakistan-based Jaish-e-Mohammed (JeM) terrorist group was responsible for a February 2018 attack on an Indian army camp in Kashmir and a February 2019 attack on Indian security forces in Kashmir—the deadliest single terrorist attack in the disputed region since the eruption of an insurgency in 1989.[REF]

Following the 2019 attack, India launched an even more daring cross-border raid. For the first time since the Third India–Pakistan War of 1971, the Indian air force crossed the LoC and dropped ordnance inside Pakistan proper (as opposed to disputed Kashmir), targeting several JeM training camps in Khyber Pakhtunkhwa province.[REF] Delhi stressed that the “non-military” operation was designed to avoid civilian casualties and was preemptive in nature because India had credible intelligence that JeM was attempting other suicide attacks in the country.

In response, Pakistan launched fighter jets to conduct their own strike on targets located on India’s side of the LoC in Kashmir, prompting a dogfight that resulted in the downing of an Indian MiG-21. Pakistan released the captured MiG-21 pilot days later, ending the brief but dangerous crisis.[REF] Skirmishes at the LoC continued through 2020, but by early 2021, India and Pakistan were experiencing at least a partial diplomatic thaw as both countries dealt with the global COVID-19 pandemic. That February, both countries agreed to observe a strict cease-fire along the LoC, and in March, Pakistan’s Chief of Army Staff, General Qamar Javed Bajwa, declared in a speech that “it is time to bury the past and move forward.”[REF]

In March 2022, India accidentally fired a cruise missile into Pakistan. The unarmed missile flew roughly 100 kilometers into Pakistan and crashed harmlessly without casualties. The Indian government blamed a “technical malfunction” during “routine maintenance.”[REF] Pakistan called the launch irresponsible and demanded a “joint probe to accurately establish the facts” in a response that one correspondent characterized as “measured.”[REF]

In January 2023, India notified Pakistan that it was seeking modification of the more than six-decade-old Indus Water Treaty, which governs water-sharing arrangements between the two countries, after Pakistan objected to the construction of an Indian dam on the Chenab river.[REF] India sent another notification in September 2024 requesting that the terms of the treaty be renegotiated, but to no avail.

In a March 2025 interview, Indian Prime Minister Modi showed little appetite for a grand rapprochement with Pakistan, noting that “every noble attempt at fostering peace was met with hostility and betrayal” and urging Pakistan to “abandon the path of terrorism.”[REF] In April 2025, India accused Pakistan of backing the terrorists who committed the Pahalgam terrorist attack in Indian-administered Jammu and Kashmir. In May 2025, in the wake of the terrorist attack, India and Pakistan engaged in a brief military conflict in which they exchanged air, missile, and drone strikes. After four days, both sides announced a cease-fire, which thus far has lasted.[REF]

India. During the Cold War, U.S.–India military cooperation was minimal except for a brief period during and after the China–India border war in 1962 when the U.S. provided India with supplies, arms, and ammunition. The rapprochement was short-lived, and the U.S. suspended arms and aid to India following the second Indo–Pakistan war in 1965.

The relationship was largely characterized by mistrust in the 1970s under the Nixon Administration, and America’s ties with India hit a low point during the third Indo–Pakistan war in 1971 when the United States deployed the aircraft carrier USS Enterprise toward the Bay of Bengal in a show of support for Pakistani forces. Months earlier, India had signed a major defense treaty with the Soviet Union. India’s close defense ties to Russia and America’s close defense ties to Pakistan left the two countries estranged for the duration of the Cold War.

Military ties between the United States and India began to improve dramatically under the George W. Bush Administration following the 9/11 terrorist attacks in 2001 and the signing of a 10-year defense partnership and landmark civil nuclear deal in 2005.[REF] More recently, the two sides have established a robust strategic partnership based on mutual concerns about China’s increasingly belligerent behavior and converging interests in countering regional terrorism and promoting a “free and open Indo-Pacific.”[REF] The U.S. has supplied India with more than $25 billion worth of U.S. military equipment since 2008, including C-130J and C-17 transport aircraft, P-8 maritime surveillance aircraft, Chinook airlift helicopters, Apache attack helicopters, artillery batteries, drones, and Firefinder radar.[REF] The two countries also have several information-sharing and intelligence-sharing agreements in place, including one that covers commercial shipping in the Indian Ocean.[REF]

Defense ties have advanced at an accelerated rate since the election of Prime Minister Modi in 2014. In 2015, the U.S. and India agreed to renew and upgrade their 10-year Defense Framework Agreement. In 2016, the two governments finalized the text of a Logistics Exchange Memorandum of Agreement (LEMOA) that allows each country to access the other’s military supplies and refueling capabilities through ports and military bases, and the U.S. designated India a “major defense partner,” a designation unique to India that is intended to facilitate its access to American defense technology.[REF] Since then, Indian and U.S. warships have begun to offer each other refueling and resupply services at sea.[REF] In October 2020, U.S. P-8 maritime surveillance aircraft were refueled for the first time at an Indian military base in the Andaman and Nicobar Islands near the mouth of the Strait of Malacca.[REF]

America’s strategic and defense ties with India advanced in several important ways during the first Trump Administration. In 2018, India was granted STA-1 status, which eases controls on exports of advanced defense technology.[REF] India is the third Asian country after Japan and South Korea to be granted STA-1 status. In the same year, India established a permanent naval attaché representative to U.S. Central Command in Bahrain, fulfilling a long-standing request from New Delhi.

In 2018, the two countries also signed the Communications Compatibility and Security Agreement (COMCASA), which will allow the U.S. to sell India encrypted communications equipment and create secure channels for communication between the Indian and U.S. militaries.[REF] In 2020, the U.S. and India signed the Basic Exchange Cooperation Agreement (BECA), which creates a framework for the sharing of geospatial intelligence.[REF]

Beyond these “foundational” or “enabling” military agreements, the two countries have signed an agreement on Helicopter Operations from Ships Other Than Aircraft Carriers (HOSTAC) and an Industrial Security Annex (ISA) that allows the U.S. to share classified information with private Indian defense firms.[REF] The two countries also have initiated a new 2+2 defense and foreign ministers dialogue while reviving the Quad grouping, which joins India and the U.S. with Australia and Japan.[REF] In 2020, the four countries held the first Quad naval exercise since 2007. When a deadly crisis erupted at the China–India border in 2020, the Trump Administration provided India with two advanced surveillance drones and cold-weather gear for Indian soldiers.

In recent years, India has made additional purchases of U.S. military hardware, including C-17 transport aircraft, Apache attack helicopters, MH-60R Seahawk multi-mission helicopters, Sig Sauer assault rifles, and M777 ultralight howitzer artillery guns.[REF] It also is reportedly considering the purchase of 30 armed MQ-9 reaper drones (10 each for the three branches of its military) for $3 billion and a half-dozen highly capable P-8I maritime aircraft (to supplement the dozen currently in operation) for nearly $2 billion.[REF]

New Delhi and Washington regularly hold joint annual military exercises across all services. They include the Yudh Abhyas army exercises, Red Flag air force exercises, and Malabar naval exercise, which added Japan and Australia as permanent participants in 2012 and 2020, respectively. In late 2019, India and the U.S. held their first tri-service military exercise, Tiger Triumph.[REF] In February 2022, the U.S. Navy participated for the first time in the MILAN naval exercise, a multilateral exercise in the Bay of Bengal that was led by the Indian navy and involved the navies of more than a dozen countries.

At the April 2022 India–U.S. 2+2 Ministerial Dialogue in Washington, the two sides signed “a Space Situational Awareness arrangement” and “agreed to launch an inaugural Defense Artificial Intelligence Dialogue.”[REF] They also committed to exploring the coproduction of Air-Launched Unmanned Aerial Vehicles under the Defense Trade and Technology Initiative (DTTI). In addition, India agreed “to join the Combined Maritime Forces Task Force…to expand multilateral cooperation in the Indian Ocean,” and the two sides agreed to “explore possibilities of utilizing Indian shipyards for repair and maintenance of ships of the U.S. Maritime Sealift Command to support mid-voyage repair of U.S. naval ships.”[REF] The U.S. Department of Defense assessed that these initiatives “will allow the U.S. and Indian militaries to work more seamlessly together across all domains of potential conflict” and “jointly meet the challenges of this century.”[REF]

In October 2022, the U.S. Army conducted joint exercises with the Indian army in the Himalayas roughly 50 miles from the disputed China–India border. During a visit to India earlier in 2022, “the US Army’s Pacific Commanding General Charles Flynn described China’s military build-up near the disputed border as ‘alarming.’”[REF]

In February 2023, the Biden Administration revealed that it was considering an application from General Electric for joint production of F414 jet engines for fighter aircraft that are produced in India. The Administration committed to an “expeditious review” of the application.[REF] Jet engine technology is among the United States’ most advanced, valuable, and sensitive military secrets; any technology transfer arrangement that included adequate safeguards would therefore mark a qualitative evolution of the India–U.S. defense partnership to exceed even some of America’s legacy treaty alliances.

In May 2024, the two sides conducted their first space defense tabletop exercise. In August 2024, they signed a Security of Supply Arrangement (SOSA), enhancing the mutual supply of defense goods and services.[REF] In October 2024, India agreed to purchase 31 U.S. MQ-9B drones for all three Indian services for roughly $3.8 billion.[REF] Recent years also have seen the first demonstration of the Javelin and Stryker systems in India and deployment of the first Indian Liaison Office to U.S. Special Operations Command.

During Prime Minister Modi’s February 2025 visit to Washington, President Trump for the first time offered to sell India the advanced U.S. fifth-generation F-35 fighter. During that visit, the two sides announced a range of new cooperative initiatives that included an Autonomous Systems Industry Alliance (ASIA); a new Catalyzing Opportunities for Military Partnership, Accelerated Commerce and Technology for the 21st Century (COMPACT) initiative; a Transforming the Relationship Utilizing Strategic Technology (TRUST) initiative; a new India–U.S. Strategic Mineral Recovery Initiative; and a U.S.–India AI infrastructure road map. Indian and U.S. private-sector firms also announced that they jointly produce sonobuoys and would collaborate on AI-driven maritime systems capable of enhancing undersea warfare and drone-swarming capabilities. Finally, they agreed to enhance cooperation on nuclear energy including small modular reactors. Micron Technology, an American semiconductor firm, also pledged to spend more than $2.75 billion on construction of an assembly and test facility in India. In 2025, the U.S. National Aeronautics and Space Administration and India’s space agency for the first time will jointly conduct scientific research onboard the International Space Station.

During the May 2025 India–Pakistan conflict, the Indian armed forces achieved mixed results. Indian missile strikes successfully targeted multiple Pakistani targets, the defenders of which had only limited success at intercepting them, while India’s integrated air and missile defenses were able to intercept Pakistani strikes. However, Pakistan used Chinese-provided jets to down from one to three Indian jets. The United States did not directly mediate the talks but nevertheless played a critical role in talking to both sides to facilitate a cease-fire.[REF]

Quality of Key Allied or Partner Armed Forces in Asia

Because Asia lacks an integrated, regional security architecture along the lines of NATO, the United States partners with most of the region’s nations on a bilateral basis. This means that there is no single standard to which all of the local militaries aspire; instead, capabilities are influenced by local threat perceptions, institutional interests, physical conditions, historical factors, and budgetary considerations.

Moreover, most Asian militaries have limited combat experience, particularly experience in high-intensity air or naval combat. Some, like Malaysia, have not fought an external war since gaining independence in the mid-20th century. The Indochina wars—the most recent high-intensity conflicts—are now more than 50 years in the past. It is therefore unclear how well Asia’s militaries have trained for future warfare and whether their doctrines will meet the exigencies of wartime realities.

Based on examinations of equipment, we assess that several Asian allies and friends have potential military capabilities that are both substantial and supported by robust defense industries and significant defense spending. The defense budgets of Japan, South Korea, and Australia are estimated to be among the world’s 15 largest, and the three countries’ military forces field some of the world’s most advanced weapons, including F-35s in the militaries of all three countries; airborne early warning (AEW) platforms; Aegis-capable surface combatants and modern diesel-electric submarines; and third-generation main battle tanks. As noted, all three nations are also involved in the production of F-35 fighters.

At this point, both the Japanese and Korean militaries arguably are more capable than most European militaries, at least in terms of conventional forces. Japan’s Self Defense Forces and South Korea’s military field more tanks, principal surface combatants, and combat-capable aircraft than are fielded by their European counterparts.

Both South Korea and Japan are also increasingly interested in developing missile defense capabilities, including joint development and coproduction in the case of Japan. After much negotiation and indecision, South Korea deployed America’s Terminal High Altitude Area Defense (THAAD) missile defense system on the peninsula in 2017.[REF] South Korea also has the Korea Air and Missile Defense system, which is comprised of Patriot Advanced Capacity-3 (PAC-3) and indigenous Chunggung medium-range missile interceptors, and is developing a long-range missile defense system in pursuit of an indigenous missile defense capability.

Japan’s Aegis-class destroyers are equipped with SM-3 missiles, and the government decided in 2017 to install the Aegis Ashore missile defense system to supplement its Patriot missile batteries.[REF] In June 2020, citing the potential for the interceptor missile’s first-stage booster to fall onto populated areas, Tokyo unexpectedly cancelled plans to build two Aegis Ashore missile defense sites. Other likely factors in the decision include the program’s overall cost, inept handling of the site-selection process, and government unwillingness to press national objectives against local resistance.[REF] Currently, Tokyo plans to build an additional two Aegis-capable ships to compensate for cancellation of the Aegis Ashore project.

India now has the world’s fourth largest military budget (approximately $75 billion in 2025) and second largest military (approximately 1.5 million personnel).[REF] The Indian navy is one of the few in the world to operate indigenously developed aircraft carriers and nuclear submarines; it commissioned its first indigenously built aircraft carrier in September 2022 and is now operating a refitted Russian carrier. Both conventional (non-nuclear) carriers are around 45,000 tons; a second, 65,000-ton conventional indigenous carrier is under construction and expected to enter service in the early 2030s. India also operates 17 diesel electric submarines and one nuclear-powered ballistic missile submarine, the Arihant, and has negotiated deals for the leasing of three Russian Akula-class submarines for 10 years each, the first in 1988, the second in 2012, and the third in 2019.[REF]

The Indian air force operates several world-class platforms, including American-built P-8 Poseidon surveillance aircraft and Apache attack helicopters, as well as C-130J and C-17 heavy transport aircraft. Its combat aircraft fleet is comprised of European, Russian, and Indian platforms with the most advanced being the Sukhoi Su-30MKI.

The Indian army deploys a large fleet of Russian-origin tanks, advanced missile defense systems like the S-400, and the U.S.-origin M777 light howitzer. India also hosts advanced ballistic and cruise missile capabilities that include indigenously developed, long-range, nuclear-capable ICBMs and the supersonic, nuclear-capable BrahMos cruise missile developed jointly with Russia.

Although its small population and physical borders limit the size of its military, Singapore fields some of the region’s highest-quality forces. Its ground forces can deploy third-generation Leopard II main battle tanks, and its fleet includes four conventional submarines (to be replaced by four new, more capable submarines from Germany)[REF] and six frigates and eight missile-armed corvettes. Its air force has F-15E Strike Eagles and F-16s as well as one of Southeast Asia’s largest fleets of airborne early warning and control aircraft (G550-AEW aircraft) and two squadrons of aerial refuelers, one comprised of KC-130 tankers and the second of Airbus A330 Multi Role Tanker Transport aircraft, that can help to extend range or time on station.[REF]

In January 2020, the U.S. Department of State cleared Singapore to purchase “four short-takeoff-and-vertical-landing F-35 variants with an option for eight more of the ‘B’ models.” Delivery is scheduled to begin in 2026.[REF] In February 2024, Singapore announced plans to purchase eight F-35A fighter jets, which will bring its total F-35 fleet to 20 by the 2030s.[REF]

Australia’s very capable armed forces are smaller than NATO militaries but have major operational experience, having deployed to Iraq and Afghanistan as well as to help the Philippines with its southern insurgency. The Australian military deploys advanced surveillance aircraft and AWACS, advanced diesel-electric submarines, F-18 and F-35 fighter aircraft, and modern frigates and destroyers. Under the AUKUS arrangement, Australia will purchase three U.S. Virginia-class nuclear-powered submarines by the early 2030s, after which Australia and the U.K. will jointly develop a new class of nuclear-powered submarines to be based on U.S. designs and delivered in the late 2030s to early 2040s.[REF]

At the other extreme, the Armed Forces of the Philippines are among the region’s weakest military forces. Having long focused on waging counterinsurgency campaigns while relying on the United States for its external security, the Philippines spent only 1.4 percent of GDP on its military in 2022.[REF] The Philippine navy’s most modern ships are three former U.S. Hamilton-class Coast Guard cutters. The Philippine navy has taken delivery of new South Korean–built frigates and is set to buy several other South Korean–built naval vessels.[REF] The Philippines also has purchased 12 light attack fighter aircraft from South Korea and has been cleared to acquire 12 new American F-16s.[REF] In January 2022, the Philippines signed a deal worth more than $374 million to acquire BrahMos supersonic cruise missiles.[REF]

Though not a formal ally, Taiwan is also vitally important to U.S. interests, and its military preparedness has been a growing concern for U.S. policymakers. Taiwan has a strong professional military, but it is vastly outnumbered by China’s. Taiwan’s conscription program has gradually deteriorated in recent decades. Administrations from both of Taiwan’s main political parties gradually decreased the length of mandatory conscription from over two years in 2000 to just four months in 2013 with a goal of eventually transitioning to all-volunteer armed forces.[REF] With cross-Strait tensions surging, the government reimplemented one full year of conscription for able-bodied men starting in 2024.[REF] While Washington welcomed this much-needed course correction, training of Taiwan’s conscripts remains insufficient, and a “substitute service” scheme continues to allow many able-bodied young men to forego military service in favor of alternative activities that often do little to strengthen the island’s security.

Taiwan also faces criticism in Washington for not spending enough on its military. Although Taiwan consistently spends more money on defense than many formal U.S. allies spend and plans to increase its spending to 3 percent of GDP in 2025, this is not perceived as enough to counter the threat from China; and while Taiwan spends a higher proportion of its total government budget on defense than is spent even by the U.S., it is still not enough to support acquisition of the equipment, technology, and talent necessary to compete with a military as large and technologically advanced as China’s.

Some in Washington’s policy community openly call for Taipei to spend 10 percent of its GDP on defense, but such a percentage is not possible given the island’s political and social circumstances.[REF] Adding to the difficulty, the arms and equipment Taiwan purchases from the U.S. are consistently delayed, and this has led to a $21.5 billion backlog as of February 2025.[REF] This not only impedes Taiwan’s military preparedness; it also strengthens political arguments in Taiwan against spending more on defense.[REF]

The armed forces of American allies from outside the region, particularly those of France and the United Kingdom, should also be mentioned. France has overseas bases in New Caledonia and the South Pacific, locally based assets, and 4,150 personnel in the region.[REF] It also conducts multiple naval deployments each year out of Metropolitan France. The U.K. is similarly active in the region and, given its unparalleled integration with U.S. forces, can employ its capability directly in pursuit of shared objectives. It has a naval logistics facility in Singapore and Royal Gurkhas stationed in Brunei and has been an integral part of a U.S.-led mission to monitor seaborne evasions.

Relationships with the People’s Republic of China and Russia

China. The People’s Republic of China is the U.S.’s most powerful and capable adversary. Its power, both military and economic, relative to that of the United States outstrips the threat posed by the Soviets at the height of their power. Much of what the United States does today in the Indo-Pacific is aimed at deterring and, if necessary, defeating Chinese aggression.

China enjoys a broad range of relationships in the Indo-Pacific, and in most cases, its presence in regional capitals, both diplomatic and economic, has been expanding steadily for more than two decades. China is the top trading partner for most Indo-Pacific nations, including U.S. partners and allies like Japan, South Korea, and India. (It is also America’s top trading partner outside of North America.) On balance, the majority of trade by these partners and allies is with Western nations, which underscores the importance of coordination in economic statecraft.

China’s economic reach was further enhanced by its Belt and Road Initiative, through which Beijing spent over $100 billion investing in infrastructure projects across the Eurasian landmass and beyond between 2015 and 2025. The BRI has begun to fizzle out in recent years as China’s slowing economy has shrunk the amount of capital available for frontier infrastructure investments and as several of China’s BRI investments have petered out, proven to be unprofitable, or generated a backlash in the host country. Nonetheless, the economic and diplomatic foothold China established in many countries through the BRI has endured.

In addition to being the top trading and investment partner for many Asian nations, China is expanding its influence through technology investments. Chinese infrastructure giants like Huawei are building out telecommunications networks across Asia even as security and espionage-related concerns have limited their reach inside the West and select countries like India and Japan.

China is also a much more active diplomatic partner than are many of its Western counterparts, generally sending high-level representation to regional diplomatic gatherings to which the U.S. government sends lower-level representation—if it attends at all. For many regional capitals, China’s simply “showing up” counts for a great deal. Yet Beijing’s often heavy-handed diplomatic tone has worked against what otherwise would have been successes. The Chinese government also spends significant capital and energy on its courting of Asian elites, offering all-expenses-paid trips to China and lucrative financial opportunities. The large ethnic Chinese diaspora in countries like Indonesia, Thailand, Malaysia, and Singapore offers additional linkages to Southeast Asia.

Even though China’s economic and diplomatic reach is expansive and growing, its political relationships across Asia reflect a more mixed picture with security concerns about China at elevated or rising levels across much of the region. China’s geopolitical relationships span a broad spectrum and include veritable Chinese client states like Cambodia and Laos; intimate defense partners like Russia, Pakistan, Iran, and North Korea; a large group of relative “neutrals” like Indonesia and Malaysia in Southeast Asia, Nepal and Bangladesh in South Asia, or the “Stans” of Central Asia (Kazakhstan, Tajikistan, Turkmenistan, Uzbekistan, and Kyrgyzstan); countries with more elevated levels of friction with China over historical issues or their closeness to the U.S. like Vietnam, Singapore, Australia, South Korea, or the Pacific Islands; and countries like Japan, India, the Philippines, and the self-governing island of Taiwan that are engaged in active territorial disputes with China that cause their relations with Beijing to be fairly antagonistic.

Thus, while China enjoys broad economic relations across the Indo-Pacific and relatively positive relations with most capitals including the large number of “neutrals,” it is worth noting that the handful of countries that are more openly antagonistic to Beijing, while small in number, are disproportionately large and powerful. The U.S. economy ($29.2 trillion) is still larger than China’s ($18.8 trillion) in nominal GDP terms, and the disparity grows larger when partners and allies are included. China and its close strategic partners—Russia, Iran, North Korea, and Pakistan—enjoy a combined GDP of $21.8 trillion. The Quad nations, the Philippines, and Taiwan combined roughly double that figure to $42 trillion in nominal GDP. If European allies are added, the figure surpasses $60 trillion.

Russia. Russia’s political and economic ties across the Indo-Pacific are far less expansive than China’s. This is partly a byproduct of their disparity in size: China’s economy is nearly 10 times larger than Russia’s. It is also a product of geography as Russia’s population centers and historical orientation historically have been Western-facing. Over 75 percent of Russia’s population lives in “European Russia” west of the Urals despite its being only 25 percent of Russia’s landmass.

Russia began “looking east” much more vigorously only after its 2014 invasion of Crimea and the resulting wave of Western sanctions and isolation led Moscow to conclude that its future lies in a closer strategic and energy partnership with China. Since that time, the China–Russia tactical partnership has evolved into a much deeper and broader comprehensive strategic partnership. China is now Russia’s closest ally in Asia and likely its closest ally overall, save for veritable client states like Belarus.

Russia still exerts extraordinary influence over the former Soviet Republics of Central Asia—Kazakhstan, Tajikistan, Turkmenistan, Uzbekistan, and Kyrgyzstan—but what was once Russia’s exclusive domain is now a more open playing field as China has slowly become a top economic and diplomatic partner of choice for many of these five countries. Russia’s reach into South, Southeast, and East Asia is much more limited, although it does maintain robust defense ties with a number of countries weaned onto Soviet military hardware during the Cold War. In 2024, the top three destinations for Russian arms exports were China, India, and Kazakhstan. These arms exports have shrunk substantially by volume since Russia’s invasion of Ukraine in 2022, but other countries like Burma, Vietnam, and Egypt remain large importers of Russian arms.

The Russian military has also sustained a robust naval presence in the Indo-Pacific. In recent years, it has taken part in increasingly sophisticated military exercises with China, deployments of naval forces that have provocatively circumnavigated Japan and operated near sensitive undersea cables near Taiwan. Russia also has one active territorial dispute in the region: a dispute with Japan over the Kuril Islands, four islands occupied by the Soviet Union in 1945 following Japan’s surrender at the end of World War II. Technically, Japan and Russia have yet to sign a peace treaty, and ongoing talks to that end were suspended after Japan imposed sanctions on Russia following its invasion of Ukraine.

U.S. Force Presence and Infrastructure: U.S. Indo-Pacific Command

Established in 1947 as U.S. Pacific Command, U.S. Indo-Pacific Command (USINDOPACOM) is the oldest and largest of America’s unified commands. According to its website:

USINDOPACOM protects and defends, in concert with other U.S. Government agencies, the territory of the United States, its people, and its interests. With allies and partners, USINDOPACOM is committed to enhancing stability in the Asia–Pacific region by promoting security cooperation, encouraging peaceful development, responding to contingencies, deterring aggression, and, when necessary, fighting to win. This approach is based on partnership, presence, and military readiness.[REF]

USINDOPACOM’s area of responsibility (AOR) “encompasses about half the earth’s surface, stretching from the waters off the west coast of the U.S. to the western border of India, and from Antarctica to the North Pole.” Its 38 countries represent “more than 50 percent of the world’s population” and include two of the world’s three largest economies and 10 of the 14 smallest as well as “the most populous nation in the world [India], the largest democracy [also India], and the largest Muslim-majority nation [Indonesia]. More than one third of Asia-Pacific nations are smaller, island nations that include the smallest republic in the world [Nauru] and the smallest nation in Asia [Maldives].”[REF] By any meaningful measure, the Indo-Pacific is also the world’s most militarized region, with “seven of the world’s ten largest standing militaries” and “five of the world’s declared nuclear nations” in addition to “five countries allied with the United States through mutual defense treaties.”[REF]

USINDOPACOM’s 11 component commands include:[REF]

• U.S. Army Pacific. USARPAC is the Army’s component command in the Pacific. Headquartered in Hawaii and with “more than 107,000 Soldiers and Civilians,” it supplies Army forces as necessary for various global contingencies. The command lists 19 subordinate units: 8th Army (South Korea); I Corps (Washington); 25th Infantry Division (Hawaii); 11th Airborne Division (Alaska); 94th Air & Missile Defense Command (Hawaii); 8th Theater Sustainment Command (Hawaii); 7th Infantry Division (Washington); 2nd Infantry Division (Washington); 5th Security Force Assistance Brigade (Washington); 1st Multi-Domain Task Force (Washington); 3rd Multi-Domain Task Force (Hawaii); 196th Infantry Brigade (Hawaii); 18th Medical Command (Hawaii); 311th Signal Command (Hawaii); U.S. Army Japan (Japan); 351st Civil Affairs Command (Hawaii); 9th Mission Support Command (Hawaii); 5th Battlefield Coordination Detachment (Hawaii); and 500th Military Intelligence Brigade (Hawaii).[REF]
• U.S. Pacific Air Forces. With 46,000 servicemembers, PACAF is responsible for planning and conducting defensive and offensive air operations in the Asia–Pacific region.[REF] It has three numbered air forces under its command: 5th Air Force (Japan); 7th Air Force (Korea); and 11th Air Force (Alaska).[REF] The 5th Air Force includes the 374th Airlift Wing, 18th Wing, and 35th Fighter Wing. The wings maintain C-130 aircrews, C-12s, UH-1s, F-15s, F-16s, KC-135 refuelers, E-3 Airborne Warning and Control (AWACS) System aircraft, and HH-60G Pave Hawk rescue helicopters. The 7th Air Force operates out of Osan Air Base and Kunsan Air Base, which host the 51st Fighter Wing and 8th Fighter Wing. The wings are made up of three squadrons that include F-16s: the 35th Fighter Squadron, 36th Fighter Squadron, and 80th Fighter Squadron. The 11th Air Force is headquartered in Joint Base Elmendorf–Richardson and is the force provider for Alaskan Command. Other forces that regularly come under PACAF command include B-52, B-1, and B-2 bombers. The 11th Air Force’s 354th Fighter Wing at Eielson Air Force Base completed the integration of 54 “combat-coded” F-35A aircraft in April 2022, increasing the number of squadrons to four.[REF]
• U.S. Pacific Fleet. PACFLT normally controls all U.S. naval forces committed to the Pacific. Composed of 11 subordinate commands and approximately 200 ships, 1,500 aircraft, and 150,000 military and civilian personnel,[REF] PACFLT is organized into the Seventh Fleet, headquartered in Japan, and the Third Fleet, headquartered in California. The Seventh Fleet includes 50–70 ships and submarines, 150 aircraft, and more than 27,000 sailors and Marines, including the only American carrier strike group (CTF-70, ported at Yokosuka, Japan) and amphibious group (CTF-76, ported at Sasebo, Japan) that are home-ported abroad.[REF] The Third Fleet’s AOR extends from the West Coast of the United States to the International Date Line and includes the Alaskan coastline and parts of the Arctic.[REF] Third Fleet component units include four carrier strike groups (CSGs). Since 2015, the conduct of Freedom of Navigation Operations (FONOPS) that challenge excessive maritime claims (a part of the Navy’s mission since 1979) has assumed a higher profile because of several well-publicized operations in the South China Sea. Both the Trump and Biden Administrations have maintained a high frequency of these operations.
• U.S. Marine Forces Pacific. With its headquarters in Hawaii, MARFORPAC “is the largest operational command in the Marine Corps” and “comprises two-thirds of the Marine Corps’ active-duty combat forces.”[REF] Specifically, the I Marine Expeditionary Force (I MEF) is headquartered at Camp Pendleton, California, and centered on the 1st Marine Division, 3rd Marine Air Wing, and 1st Marine Logistics Group, and the III Marine Expeditionary Force (III MEF) is headquartered on Okinawa and centered on the 3rd Marine Division, 1st Marine Air Wing, and 3rd Marine Logistics Group. The 1st Marine Division “provides fully trained units and personnel in support of Marine Rotational Force–Darwin, Marine Expeditionary Units, and the Unit Deployment Program to Okinawa, Japan.”[REF] The 3rd Marine Division “operates as a Stand-In Force in the first island chain to secure, seize, or defend key maritime terrain in order to deny and disrupt adversary actions in support of the Fleet, the Joint Force, and partnered and allied forces.”[REF]
• U.S. Special Operations Command Pacific. SOCPAC “is a sub-unified command of USSOCOM [U.S. Special Operations Command] under the operational control [of] U.S. Indo-Pacific Command and serves as the functional component for all special operations missions deployed throughout the Indo-Asia-Pacific region.” Its “area of focus covers 36 countries and encompasses half of the Earth’s surface.”[REF] Among the special operations forces under SOCPAC’s control are Navy SEALs; Naval Special Warfare units; Army Special Forces (Green Berets); and Special Operations Aviation units in the Pacific region, including elements in Japan and South Korea. Its core activities include (among others) counterinsurgency and unconventional warfare, hostage rescue and recovery, training of foreign security forces, and support for “DOD humanitarian activities conducted outside the US and its territories to relieve or reduce human suffering, disease, hunger, or privation.”[REF]
• U.S. Forces Korea. USFK’s “mission is to deter aggression and if necessary, defend the Republic of Korea to maintain stability in Northeast Asia.”[REF] It is responsible for organizing, training, and equipping U.S. forces on the Korean Peninsula as directed by USINDOPACOM in support of the U.S.–South Korean Combined Forces Command (CFC) and United Nations Command (UNC). USFK’s components include U.S. Eighth Army; U.S. Seventh Air Force; Commander, U.S. Naval Forces Korea (CNFK); Marine Corps Forces Korea (MARFOR-K); and Special Operations Forces Korea (SOCKOR).[REF]
• U.S. Forces Japan. Operating with approximately 60,000 U.S. Army, Marine Corps, Navy, Air Force, and Space Force Corps personnel, USFJ “serves to strengthen the US–Japan Alliance to help deter and, if necessary, defeat threats against Japan.” It is “transforming into a Joint Force Headquarters, aiming to strengthen the alliance and enhance integrated operational capabilities.”[REF]
• Joint Interagency Task Force West. JIATF-W, “in coordination with U.S. law enforcement, interagency and partner nations, combats, disrupts and dismantles drug trafficking and transnational criminal organizations, to protect U.S. lives, interests, and regional stability in the Indo-Pacific.”[REF] Its “top priority is supporting law enforcement in their efforts to reduce the illicit flow of fentanyl, methamphetamine, Amphetamine-Type Stimulants and precursors intended for U.S. markets.”[REF]
• U.S. Space Forces–Indo-Pacific. USSPACEFOR-INDOPAC “enhances stability in the Indo-Pacific region by promoting interoperability and integration from planning and programming through fielding and execution to respond to contingencies, deter aggression, and maintain space superiority in pursuit of a free and open Indo-Pacific.”[REF] Its three commands include Combat Forces Command (CFC), Petersen Space Force Base, Colorado; Space Systems Command (SSC), Los Angeles, California; and Space Training and Readiness Command (STARCOM), Patrick Space Force Base, Florida.[REF]
• U.S. Coast Guard Pacific Area. USCG-PACIFIC AREA has a “74 million square mile operational area” and “more than 13,000 active duty, reserve, civilian and volunteer employees” with 11 statutory missions: “preserve the global supply chain, protect our fragile marine ecosystems, ensure U.S. sovereignty in the Polar regions, combat transnational organized crime, support global humanitarian response operations and preserve the U.S. as a free and enduring nation.” Its four regional commands—the 11th, 13th, 14th, and 17th Districts—cover “much of the Pacific Ocean, North America and South America.”[REF]
• Center for Excellence in Disaster Management & Humanitarian Assistance. CFE-DM “builds crisis response capacity in US, Allies and Partner militaries across the Indo-Pacific to save lives before, during and after emergencies.”[REF] Its Humanitarian Assistance Response Training (HART) programs prepare trainees “to respond more effectively during civilian-led humanitarian assistance and foreign disaster response missions” and to “support[], and when necessary, conduct[] humanitarian assistance before, during, and after combat operations.”[REF] Its Applied Research and Information Sharing (ARIS) Academic Partnership Program (APP) “endeavors to foster capacity through research into emerging issues in the sphere of civil-military coordination, preparedness and response for disaster management and humanitarian assistance (DMHA).”[REF]

Key Infrastructure That Enables Expeditionary Warfighting Capabilities

Any planning for operations in the Pacific will inevitably be dominated by the “tyranny of distance.” Because of the extensive distances that must be traversed, even Air Force units will take one or more days to deploy, and ships measure steaming time in weeks. A ship sailing at 20 knots, for instance, requires nearly five days to get from San Diego to Hawaii. From there, it takes seven more days to get to Guam; seven days to Yokosuka, Japan; and eight days to Okinawa—assuming that ships encounter no interference along the way.[REF]

China’s growing anti-access/area denial (A2/AD) capabilities, which range from an expanding fleet of modern submarines to anti-ship ballistic and cruise missiles, increase the operational risk for deployment of U.S. forces in the event of conflict. China’s capabilities jeopardize American combat forces that would flow into the theater for initial combat and would continue to threaten the logistical support needed to sustain American combat power in the ensuing days, weeks, and months.

American basing structure in the Indo-Pacific region, including access to key allied facilities, is therefore both necessary and increasingly at risk.

American Facilities

Hawaii. Much as it was in the 20th century, Hawaii remains the linchpin of America’s ability to support its position in the Western Pacific. If the United States cannot preserve its facilities in Hawaii, both combat power and sustainability become moot. The United States maintains air and naval bases, communications infrastructure, and logistical support on Oahu and elsewhere in the Hawaiian Islands. Hawaii is also a key site for undersea cables that carry much of the world’s communications and data, as well as for satellite ground stations.

Guam. The American territory of Guam is located 4,600 miles farther west. Obtained from Spain as a result of the Spanish–American War, Guam became a key coaling station for U.S. Navy ships. It was seized by Japan in World War II, was liberated by U.S. forces in 1944, and after the war became an unincorporated, organized territory of the United States.

Key U.S. military facilities on Guam include U.S. Naval Base Guam, which houses several attack submarines and possibly a new aircraft carrier berth, and Andersen Air Force Base, one of a handful of facilities that can house B-2 bombers. U.S. task forces can stage out of Apra Harbor, drawing weapons from the Ordnance Annex in the island’s South Central Highlands. On January 26, 2023, the Marine Corps reopened Marine Corps Base Camp Blaz, which will host 5,000 Marines comprising various aviation, ground combat, combat support, logistics, and headquarters units in the coming years.[REF] There is also a communications and data relay facility on the island.

Guam’s facilities have improved steadily over the past 20 years. B-2 bombers, for example, began to operate from Andersen Air Force Base in March 2005.[REF] These improvements have been accelerated and expanded even as China’s A2/AD capabilities have raised doubts about America’s ability to sustain operations in the Asian littoral. The concentration of air and naval assets as well as logistical infrastructure on Guam would make the island an attractive target in the event of conflict, and the increasing reach of Chinese and North Korean ballistic missiles only adds to this growing vulnerability.

Saipan. The U.S. military has noncombatant maritime prepositioning ships (MPS), which contain large amounts of military equipment and supplies, in strategic locations from which they can reach areas of conflict relatively quickly as associated U.S. Army or Marine Corps units located elsewhere arrive in those areas. U.S. Navy units in Saipan, Commonwealth of the Northern Marianas, support prepositioning ships that can supply Army or Marine Corps units that are deployed for contingency operations in Asia.

Allied and Other Friendly Facilities

Access to bases in Asia has long been a vital part of America’s ability to support military operations in the region. This includes, in the cases of Japan and South Korea, substantial Host Nation Support to cover the cost of labor, maintenance, and repairs of platforms based in these nations. Even with the extensive aerial refueling and replenishment skills of the U.S. Air Force and U.S. Navy, it is still essential that the United States retain access to resupply and replenishment facilities, at least in peacetime. The ability of those facilities to survive and function will directly influence the course of any conflict in the Western Pacific. Moreover, a variety of support functions, including communications, intelligence, and space support, cannot be accomplished without facilities in the region.

Today, maintaining maritime domain awareness or space situational awareness would be extraordinarily difficult without access to facilities in the Asia–Pacific region. The American alliance network is therefore a matter both of political partnership and of access to key facilities on allied soil.

Six U.S. EEZs that are rich in fish and untapped natural resources are located in an arc that stretches over 1,400 miles from Wake Island to Johnston Atoll and south 1,900 miles to American Samoa. To focus resources and enable better regional coordination, the U.S. Coast Guard Pacific Area Command and U.S. Indo-Pacific Command should establish a detachment in American Samoa. Its mission would be to identify and execute needed maritime training and infrastructure projects supporting a sustained maritime security presence while synchronizing operational (e.g., the Coast Guard’s Operation Blue Pacific) and capacity-building activities with regional partners.[REF] This region would be of strategic importance in moving military forces and sustaining them in any Asian conflict.

Finally, the United States is granted access to a number of facilities in Asian states on a contingency or crisis basis. Thus, U.S. Air Force units transited Thailand’s U-Tapao Air Base and Sattahip Naval Base during the first Gulf War and during the Iraq War, but they do not maintain a permanent presence there. Additionally, the U.S. Navy conducts hundreds of port calls throughout the region.

Diego Garcia. The American facilities on the British territory of Diego Garcia are vital to U.S. operations in the Indian Ocean and Afghanistan and provide essential support for operations in the Middle East and East Asia. The island is home to the Military Sealift Command’s Maritime Prepositioning Squadron-2 (MPSRON-2), which works with Maritime Prepositioning Squadron-3 (MPSRON-3) “to deliver a strategic power-projection capability for the Marine Corps, Army and Air Force, known as the Maritime Prepositioning Force (MPF).”[REF] Specifically, “MPF ships deliver a forward presence and rapid crisis response capability by pre-positioning equipment and supplies to various locations at sea.”[REF]

Several elements of the U.S. global space surveillance and communications infrastructure, as well as basing facilities for the B-2 bomber, are also located on the island. More recently, critical military forces staged operations directly and in support of the successful attacks on Iran’s nuclear weapons infrastructure during the June 2025 Midnight Hammer operation.

It should also be noted that the United Kingdom is seeking to transfer sovereignty of the Chagos Islands to Mauritius. This is problematic on many fronts in that Mauritius has close ties to China, which could impede the ability of the U.S. and U.K. to generate combat operations from Diego Garcia. Mauritius is also a party to the Treaty of Pelindaba, which prohibits the stationing of nuclear weapons in nations that are a party to the treaty. If the United States should wish to generate nuclear bombing missions out of Diego Garcia, it would be legally prohibited from doing so if the islands were transferred to Mauritius. Finally, according to some reporting, even if Diego Garcia was to be used as a bomber base by American or U.K. forces, the U.K. government would be required to inform Mauritius if any bombing missions generated on Diego Garcia would target a third party. This, to say the least, would undermine operational security or even mission effectiveness if the United States or the United Kingdom actually tried to use Diego Garcia as a military base.

Conclusion

The military balance in the Indo-Pacific is shifting. The unchallenged military superiority the U.S. enjoyed in the region for roughly eight decades has come to an end.

The U.S. has not had a military peer in Asia since the defeat of Japan in World War II. The Soviet Union was a military peer, but the overwhelming majority of its conventional military strength was Europe-facing; it was never more than a marginal player in the Indo-Pacific. As a result, the security order in Asia was effectively unipolar for nearly a century.

That order served Asia well. Despite being a region with unparalleled size and population— replete with numerous active territorial disputes, significant historical animosities, and the world’s largest and fastest-growing powers rising quickly—Asia has enjoyed a period of remarkable peace since the 1980s.

That peace fostered a phenomenal bout of regional prosperity: The economic growth witnessed across Asia in recent decades from India to China, Korea to Japan, and throughout ASEAN has no historical precedent. Virtually every country has benefitted from the stability and prosperity delivered by this order—perhaps none more than China, which is why it is ironic that China is seeking to challenge or overturn that order.

In recent years, China has grown demonstrably more aggressive abroad and repressive at home. Under Communist Party Chairman Xi Jinping, China’s designs on Taiwan, military intimidation of its neighbors, predatory economic practices, and challenges to America’s position in Asia have grown increasingly brazen as Beijing has begun to close key gaps in capabilities between it and the U.S.

To be sure, America still enjoys considerable strengths and assets in the region, particularly when combined with close allies and likely participants in any conflict with China, including Japan, Australia, the Philippines, and Taiwan (as well as key partners like India and South Korea), and China has fewer reliable friends on which to depend. Moreover, Russia’s ability to project force into the Western Pacific is extremely limited. The same is true of Iran, whose economy and military capabilities have been so degraded that it now struggles to project power in its own backyard. North Korea has consequential military capabilities, but its involvement in any China–U.S. conflict would almost certainly invite intervention by South Korea, which on balance would likely be a net negative for China.

Even without powerful allies, the U.S. military in many respects is still in a class of its own. It still fields an unparalleled fleet of aircraft carriers, nuclear submarines, fifth-generation fighters, missile defense systems, stealth technology, and airlift capabilities. America’s missile, space, cyber, and long-range logistics capabilities are still world class. But the United States confronts large and growing challenges vis-à-vis China, not least (as noted previously) the tyranny of distance, and the most likely scenarios for a China–U.S. conflict are nearly all in the Western Pacific. As far as the security of the homeland and the American people is concerned, that is a good thing, but it also means that virtually all of the plausible conflict scenarios have battles unfolding in China’s backyard where it enjoys considerable asymmetric advantages. Moreover, how a large-scale conflict between the world’s two superpowers, both of which are armed with nuclear weapons, would play out is unknown. Accordingly, any China–U.S. conflict has the potential to become a third world war—and in such a scenario, the American homeland might no longer be a sanctuary.

The reach of the U.S. military is unparalleled: It can do things in distant corners of the globe that the Chinese military could never dream of doing. Its “horizontal” reach is still generations ahead of China’s. But vertically, in the Indo-Pacific, those advantages dwindle. It could take U.S. assets days or weeks to reach a battlefield that China can reinforce in a matter of hours. Close to its shores, China can lean more easily on an expansive network of land-based military bases, artificial islands, and short-range to medium-range missiles.

Nor are distance and geography the only problems confronting the United States. America’s defense industrial base has been hollowed out by neglect. Its stockpiles of ammunition and fuel, as well as its sealift and airlift capabilities, may prove woefully inadequate for a protracted major-power conflict with China. The U.S. government has finally begun to take steps to revitalize its defense industrial base, but they are slow and uneven.

Moreover, it is still unclear how new technologies like drone swarms and artificial intelligence would be deployed by China and impact the battlespace. The conflict in Ukraine is offering glimpses into the future of warfare, but it is not indicative of what a major-power war between the United States and China—one likely to unfold largely in the air, at sea, and in cyberspace—would look like.

China also enjoys other advantages. Through major hacking and espionage efforts, including Salt and Volt Typhoon, Chinese agents have embedded themselves in America’s financial system, telecommunications networks, and vital infrastructure. Their ability to cause economic harm, if not entire systems failures, should not be underestimated even though the United States likely has capabilities that would enable it to cause considerable damage and mischief within China if Beijing were maliciously inclined.

In sum, the military gap with China—in China’s backyard—has narrowed significantly, and the outcome of a conflict is more uncertain than ever. On the other hand, at least for the moment, China’s leadership seems to recognize and fear that uncertainty: A “coin toss” is not great odds when your survival is potentially on the line.

Perhaps the most important dynamic keeping the peace in the Indo-Pacific today is Xi Jinping’s well-deserved anxiety about the outcome of a conflict with the U.S. Losing a war to the United States, especially over Taiwan, could threaten not only his rule and his life, but Communist Party rule as well. With China in the middle of the most shocking high-level purge of PLA commanders in generations, it is incumbent on Washington to ensure that war with America remains an unacceptably risky proposition for China’s leaders. That will require maintaining and enhancing deterrence against an increasingly powerful, irascible, and ambitious adversary.

Deterrence is built on two foundations: capability and will. Anything that diminishes U.S. capability and will in the Indo-Pacific—or perceptions of U.S. capability and will—actually risks inviting Chinese aggression. Any perceived weakening of the U.S. commitment to the region or to its allies and close security partners actually raises the likelihood of a catastrophic conflict. At the same time, continuing to underprioritize and inadequately resource the Indo-Pacific relative to other theaters does more than heighten the risk of war: It heightens the probability of a costly defeat.

Scoring the Asia Operating Environment

As with the operating environments of Europe, the Middle East, Latin America, and Africa, we assessed the characteristics of Asia as they could be expected to facilitate or inhibit America’s ability to conduct military operations to defend its vital national interests against threats. Our assessment of the operating environment utilized a five-point scale that ranges from “very poor” to “excellent” conditions and covers four regional characteristics of greatest relevance to the conduct of military operations:

1. Very Poor. Significant hurdles exist for military operations. Physical infrastructure is insufficient or nonexistent, and the region is politically unstable. The U.S. military is poorly placed or absent, and alliances are nonexistent or diffuse.
2. Unfavorable. A challenging operating environment is marked by inadequate infrastructure, weak alliances, and recurring political instability. The U.S. military is inadequately placed in the region.
3. Moderate. A neutral to moderately favorable operating environment is characterized by adequate infrastructure, a moderate alliance structure, and acceptable levels of regional political stability. The U.S. military is adequately placed.
4. Favorable. A favorable operating environment includes good infrastructure, strong alliances, and a stable political environment. The U.S. military is well placed for future operations.
5. Excellent. An extremely favorable operating environment includes well-established and well-maintained infrastructure, strong and capable allies, and a stable political environment. The U.S. military is exceptionally well placed to defend U.S. interests.

The key regional characteristics consist of:

1. Alliances. Alliances are important for interoperability and collective defense, as allies would be more likely to lend support to U.S. military operations. Indicators that provide insight into the strength or health of an alliance include whether the U.S. trains regularly with countries in the region, has good interoperability with the forces of an ally, and shares intelligence with nations in the region.
2. Political Stability. Political stability brings predictability for military planners when considering such things as transit, basing, and overflight rights for U.S. military operations. The overall degree of political stability indicates whether U.S. military actions would be hindered or enabled and reflects, for example, whether transfers of power are generally peaceful and whether there have been any recent instances of political instability in the region.
3. U.S. Military Positioning. Having military forces based or equipment and supplies staged in a region greatly facilitates America’s ability to respond to crises and presumably achieve success in critical “first battles” more quickly. Being routinely present also helps the United States to maintain familiarity with a region’s characteristics and the various actors that might act to assist or thwart U.S. actions. With this in mind, we assessed whether or not the U.S. military was well positioned in the region. Again, indicators included bases, troop presence, prepositioned equipment, and recent examples of military operations (including training and humanitarian) launched from the region.
4. Infrastructure. Modern, reliable, and suitable infrastructure is essential to military operations. Airfields, ports, rail lines, canals, and paved roads enable the U.S. to stage, launch, and logistically sustain combat operations. We combined expert knowledge of regions with publicly available information on critical infrastructure to arrive at our overall assessment of this metric.[REF]

For Asia, we arrived at these average scores (rounded to the nearest whole number):

• Alliances: 4—Favorable.
• Political Stability: 4—Favorable.
• U.S. Military Positioning: 2—Unfavorable.
• Infrastructure: 3—Moderate.

Aggregating to a regional score of: Moderate.

Endnotes