Jeff Smith, Dean Cheng, Bruce Klingner, and Walter Lohman

Ever since the founding of the American Republic, Asia has been a key U.S. area of interest for both economic and security reasons. One of the first ships to sail under an American flag was the aptly named Empress of China, which inaugurated America’s participation in the lucrative China trade in 1784. In the more than 235 years since then, the United States has held to the strategic assumption that allowing any single nation to dominate Asia would be inimical to American interests. Asia is too important a market and too great a source of key resources for the United States to be denied access. Thus, beginning with U.S. Secretary of State John Hay’s “Open Door” policy toward China in the 19th century, the United States has worked to prevent the rise of a regional hegemon in Asia, whether it was imperial Japan or the Soviet Union.

In the 21st century, Asia’s importance to the United States will continue to grow. Asia is a key source of vital natural resources and a crucial part of the global value chain in areas like electronic components. Through 2021, six of America’s top 10 trading partners were found in Asia:1

• China (third);
• Japan (fourth);
• South Korea (sixth);
• Taiwan (eighth);
• India (ninth); and
• Vietnam (10th).

America’s economic connections with these countries and others in the region and beyond contribute to a closely integrated global economy characterized by ties in production, finance, services, information, and investment. When one part of the system sneezes, other parts of the economic body get sick—as demonstrated recently and most starkly by the COVID-19 pandemic. The impact of that crisis on both supply and demand, especially with respect to technology, continues to affect defense planning, budgeting, and production in the United States and across the region. Tensions in the U.S.–China economic relationship have had a similar impact.

Economics is central to understanding political dynamics in Asia, but that is not the only important consideration. Several of the world’s largest militaries are there, including those of China, India, North and South Korea, Pakistan, Russia, and Vietnam. The United States also maintains a network of treaty alliances and security partnerships, as well as a significant military presence, in Asia, and five Asian states (China, North Korea, India, Pakistan, and Russia) possess nuclear weapons.

The region is a focus of American security concerns both because of its substantial military forces and because of its legacy of conflict. Both of the two major “hot” wars fought by the United States during the Cold War (Korea and Vietnam) were fought in Asia. Moreover, the Asian security environment is unstable. For one thing, the Cold War has not ended in Asia. Of the four states divided between Communism and democracy by the Cold War, three (China, Korea, and Vietnam) are in Asia. Neither the Korean situation nor the China–Taiwan situation has been resolved despite the fall of the Berlin Wall and the collapse of the Soviet Union.

The Cold War itself was an ideological conflict layered atop long-standing—and still lingering—historical animosities. Asia is home to several major territorial disputes, among them disputes between or among:

• Japan and Russia (Northern Territories/Southern Kurils);
• Japan, China, and Taiwan (Senkakus/Diaoyutai/Diaoyu Dao);
• Korea and Japan (Dok-do/Takeshima);
• Vietnam, China, and Taiwan (Paracels/Xisha Islands);
• China, Taiwan, Vietnam, Brunei, Malaysia, and the Philippines (Spratlys/Nansha Islands);
• India and Pakistan (Kashmir); and
• India and China (Aksai Chin and parts of the Indian state of Arunachal Pradesh).

Several of these unresolved differences could devolve into war. Chinese air and sea incursions around Taiwan—especially since Russia’s invasion of Ukraine—have generated increased concern about Taiwan’s survival as an independent nation. The situation on the Korean Peninsula is perpetually tense. And China’s increasingly aggressive presence at sea is bringing Beijing ever closer to conflict with the U.S. military and the forces of its treaty allies and security partners. On the China–India border, the two sides have come to blows in recent years.

It is in light of this instability and the reluctance of many states in the region to align with great powers that one should weigh the region’s lack of a political–security architecture. There is no Asian equivalent of NATO despite an ultimately failed mid-20th century effort to forge a parallel multilateral security architecture through the Southeast Asia Treaty Organization (SEATO). Regional security entities like the Five Power Defense Arrangement (involving the United Kingdom, Australia, New Zealand, Malaysia, and Singapore in a peacetime “arrangement” rather than an alliance) or discussion forums like the ASEAN Regional Forum (ARF) and groupings like the ASEAN Defence Ministers Meeting-Plus (ADMM-Plus) have been far weaker. There also is no Asian equivalent of the Warsaw Pact.

Instead, Asian security has been marked by a combination of bilateral alliances, mostly centered on the United States, and individual nations’ efforts to maintain their own security. In recent years, these core aspects of the regional security architecture have been supplemented by “minilateral” consultations like the U.S.–Japan–Australia and India–Japan–Australia trilaterals and the U.S.–Japan–Australia–India quadrilateral dialogue (popularly known as “the Quad”).

Nor is Asia undergirded by any significant economic architecture. Despite substantial trade and expanding value chains among the various Asian states, as well as with the rest of the world, formal economic integration is limited. There are many trade agreements among the nations of the region and among these nations and countries outside of Asia, most prominently the 15-nation Regional Comprehensive Economic Partnership (RCEP) and 11-nation Comprehensive and Progressive Agreement for Trans-Pacific Partnership (CPTPP), but there is no counterpart to the European Union or even to the European Economic Community or the European Coal and Steel Community, the precursor to European economic integration.

The Association of Southeast Asian Nations (ASEAN) is a far looser agglomeration of disparate states, although they have 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). The South Asia Association of Regional Cooperation (SAARC), which includes Afghanistan, Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka, has been less important to regional stability. It is largely ineffective, both because of the lack of regional economic integration and because of the historical rivalry between India and Pakistan.

Important Alliances and Bilateral Relations in Asia

The keys to America’s position in the Western Pacific are its alliances with Japan, the Republic of Korea (ROK), the Philippines, Thailand, and Australia, supplemented by very 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 U.S. also has a robust unofficial relationship with Taiwan.

The United States also benefits from the interoperability gained from sharing common weapons and systems with many of its allies. Many nations, for example, have equipped their ground forces with M-16/M-4–based infantry weapons and share the same 5.56 mm ammunition; they also field F-15 and F-16 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.

Consequently, in the event of conflict, the region’s various air, naval, and even land forces would be able to share information in such key areas as air defense and maritime domain awareness. This advantage is enhanced by the constant ongoing range of both bilateral and multilateral exercises, which acclimate various forces to operating together and familiarize both American and local commanders with each other’s standard operating procedures (SOPs), as well as training, tactics, and (in some cases) war plans. In addition, “enabling” military agreements allow the United States and several of its regional partners to access each other’s military facilities, share intelligence and encrypted communications and equipment, and refuel each other’s warships at sea.

While it does not constitute a formal alliance, in November 2017, Australia, Japan, India, and the U.S. reconstituted the Quad. Officials from the four countries agreed to meet in the quadrilateral format twice a year 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. 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. In March 2021, the leaders of the four nations held their first virtual summit, marking a new level of interaction. In September 2021, the four leaders held the first in-person Quad summit; it is expected that a second will be held in Japan during 2022.

Japan. The U.S.–Japan defense relationship is the linchpin 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. Changes in Japanese defense policies are now enabling an even greater level of cooperation on security issues, both between the two allies and with other countries in the region.

Since the end of World War II, Japan’s defense policy has been distinguished by Article 9 of the Japanese constitution, which states in part that “the Japanese people forever renounce war as a sovereign right of the nation and the threat or use of force as means of settling international disputes.”2 In effect, this article prohibits the use of force by Japan’s governments as an instrument of national policy. It also has led to several other associated policies.

One such policy was a prohibition against “collective self-defense.” Japan recognized that nations have a right to employ their armed forces to help other states defend themselves (in other words, to engage in collective defensive operations) but rejected that policy for itself: Japan would employ its forces only in defense of Japan. This changed in 2015. Japan passed legislation that enabled its military to exercise limited collective self-defense in certain cases involving threats to both the U.S. and Japan as well as in multilateral peacekeeping operations.

In recent years, Japan has increased its security cooperation with other Indo-Pacific democracies. This cooperation has included enhancing security agreements, participating in more multilateral military exercises, and providing ships to Southeast Asian coast guard forces.

Tokyo relies heavily on the United States—and Washington’s extended deterrence guarantee of nuclear, conventional, and missile defense forces—for its security. Japan has developed a formidable military by implementing significant changes in security legislation and procuring an impressive array of sophisticated weapons. Yet because of its pacifist constitution and the devastation wrought by its quest for regional dominance in World War II, progress in altering Japan’s security posture has always lagged behind faster-moving regional threats. The Japanese people remain deeply suspicious of any use of the military as a policy instrument—and fearful that any easing of constraints will lead Japan into military conflict. Each incremental step in expanding the role of Japan’s Self-Defense Forces has therefore been immensely controversial.

As part of its relationship with Japan, the United States maintains some 54,000 military personnel and another 8,000 Department of Defense (DOD) civilian employees in Japan under the rubric of U.S. Forces Japan (USFJ).3 These forces include, among other things, a forward-deployed carrier battle group centered on the USS Ronald Reagan; an amphibious ready 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 in addition to air and naval exercises.

The American presence is supported by a substantial American defense infrastructure throughout Japan, including Okinawa. These major 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 West Coast of the United States. They also provide key listening posts for the monitoring of Russian, Chinese, and North Korean military operations. This capability is supplemented by Japan’s growing array of space systems, including new reconnaissance satellites.

The Japanese government “pays roughly $2 billion per year to defray the cost of stationing U.S. military personnel in Japan.”4 These funds cover approximately 75 percent of the cost of deployed U.S. forces,5 including the costs of utility and labor at U.S. bases, improvements in U.S. facilities in Japan, and relocation of training exercises away from populated areas in Japan. Japan paid nearly all of the cost of new U.S. military facilities at Futenma and Iwakuni as well as a third of the cost of new facilities in Guam. It also purchases 90 percent of its weapons and defense systems from the United States.6

During bilateral Special Measures Agreement negotiations, the Trump Administration sought a 400 percent increase in Japanese contributions for remuneration above the cost of stationing U.S. troops in Japan. In January 2022, the Biden Administration reached an agreement with Japan on a new five-year cost-sharing agreement that includes incremental increases in Japanese funding, thereby resolving a major irritant in the bilateral relationship.7

The United States has long sought to expand Japanese participation in international security affairs. Japan’s political system, grounded in the country’s constitution, legal decisions, and popular attitudes, has generally resisted this effort. However, in recent years, Tokyo has become increasingly alarmed by China’s surging defense expenditures, rapidly expanding and modernizing military capabilities, and escalating aerial and maritime incursions into Japan’s territorial waters and contiguous areas. In response, Japan has reoriented its forces so that they can better counter the Chinese threat to its remote southwest islands. It also has acquired new capabilities, built new facilities, deployed new units and augmented others, improved its amphibious warfare capabilities, increased its air and sea mobility, and enhanced its command-and-control capabilities for joint and integrated operations.

Recently, the growing potential for a Taiwan crisis has led senior Japanese officials to issue increasingly bold public statements of support for Taipei and more directly align Japan’s national interests with the protection of Taiwan’s security. As yet, however, there have been no declared Japanese policy changes and no pledge to intervene directly in a military conflict to defend Taiwan or even to allow U.S. defense of Taiwan from bases in Japan.

Similarly, heightened Japanese concern about the growing North Korean missile and nuclear threats has triggered a resurgence of debate about whether the country should augment its defenses by acquiring strike capabilities, which would enable Japan to conduct an attack against targets in an opponent’s country. Japan’s legal interpretation of what is allowed under its peace constitution is not static. It has evolved in response to increasing regional threats, Japan’s improving military capabilities, and Tokyo’s perception of the strength of its alliance with Washington.

Prime Minister Fumio Kishida has stated that Japan should consider building a missile-strike capability as a “viable option” against China and North Korea, to be implemented in response to initial attacks.8 Pursuing strike capabilities would be the subject of great controversy—both among the Japanese people and among the people of neighboring countries—and would require deft public diplomacy to overcome strong resistance to such a significant shift in Japan’s post–World War II security posture. Although this is now being discussed more openly by politicians, Japanese strike capability is still only at the theoretical debate stage. Tokyo has yet to articulate strike policy, strategy, a doctrine of employment, triggering events, procurement, deployment, or how offensive systems would train in Japan.

Contentious historical issues from Japan’s brutal 1910–1945 occupation of the Korean Peninsula have been serious enough to torpedo efforts to improve defense cooperation between Seoul and Tokyo. South Korean–Japanese relations took a major downturn in 2018 when the South Korean Supreme Court ruled that Japanese companies could be forced to pay occupation reparations. In December 2018, an incident between a South Korean naval ship and a Japanese air force plane further exacerbated tensions. Japan responded in July 2019 by imposing restrictions on exports to South Korea of three chemicals that are critical to the production of semiconductors and smartphones.9 Seoul then threatened to withdraw from the bilateral General Security of Military Information Agreement (GSOMIA), which enables the sharing of classified intelligence and military information on the North Korean nuclear and missile threat. The Moon Jae-in administration relented and maintained the agreement, but there was public criticism of U.S. pressure.

The election of new leaders in South Korea and Japan has raised hopes that it might be possible to reduce tensions by separating difficult historic issues from the necessity of addressing present-day security threats. Prime Minister Kishida was responsible for two Japanese–South Korean agreements10 while he served as foreign minister, and South Korean President Yoon Seok-youl, elected in March 2022, has vowed to build a “future-oriented relationship” with Japan.11

Republic of Korea. The United States and the Republic of 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.

The U.S. is committed to maintaining 28,500 troops on the Korean Peninsula. This presence is centered mainly on the U.S. 2nd Infantry Division, rotating brigade combat teams, and a significant number of combat aircraft.

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. In concrete terms, however, it oversaw only South Korean and American forces as other nations’ contributions were gradually withdrawn or reduced to token elements.

Although the 1953 armistice ended the Korean War, 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, who is also Commander, U.N. Command, CFC reflects an unparalleled degree of U.S.–South Korean military integration. CFC returned peacetime OPCON 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.

In 2007, then-President Roh Moo-hyun requested that the United States return wartime OPCON of South Korean forces to Seoul. This decision engendered significant opposition within South Korea and raised serious military questions about the transfer’s impact on unity of command. Faced with various North Korean provocations, including a spate of missile tests as well as attacks on South Korean military forces and territory in 2010, Washington and Seoul agreed in late 2014 to postpone wartime OPCON transfer and adopt a conditions-based rather than timeline-based policy. After wartime OPCON transfer, 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 U.S. Forces Korea (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.

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, have yet to be met.12 President Yoon Seok-youl, elected in March 2009, criticized Moon’s push for a premature return of wartime OPCON from United Nations Command before Seoul had fulfilled the agreed-upon conditions.

The domestic political constraints under which South Korea’s military operates are less stringent than those that govern the operations of the Japanese military. South Korea has fought alongside the United States in every conflict since the Korean War. Seoul sent 300,000 troops to the Vietnam War, and 5,000 of them were killed. At one point, it fielded the third-largest troop contingent in Iraq after the United States and Britain. It also has conducted anti-piracy operations off the coast of Somalia and has participated in peacekeeping operations in Afghanistan, East Timor, and elsewhere.

South Korean defense planning remains focused on North Korea, especially as Pyongyang has deployed its forces in ways that optimize a southward advance and has carried out several penetrations of ROK territory by ship, submarine, commandos, and drones. The sinking of the South Korean frigate Cheonan and shelling of Yongpyeong-do in 2010, which together killed 48 military personnel, wounded 16, and killed two civilians, have only heightened concerns about North Korea.

In response to Pyongyang’s expanding nuclear strike force, South Korea created a “3K” tiered 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. The South Korean military is a sizeable force with advanced weapons and innovative military education and training. South Korean military spending has increased, and Seoul appears to be procuring the right mix of capabilities. U.S.–South Korean interoperability has improved, partly because of continued purchases of U.S. weapons systems.

Over the past several decades, the American presence on the peninsula has slowly declined. 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 so that few Americans are now deployed on the Demilitarized Zone (DMZ).

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 forces and were intended partly to deter Pyongyang as well as to give U.S. and ROK forces a chance to practice operating together. However, after the 2018 U.S.–North Korean Summit, President Donald Trump announced unilaterally that he was cancelling major bilateral military exercises because he thought they were provocative and expensive.13 The President made this decision without consulting the DOD, U.S. Forces Korea, or allies South Korea and Japan. During the next four years, the U.S. and South Korea cancelled numerous exercises and imposed constraints on additional exercises.

North Korea did not reciprocate with any diplomatic gesture or military constraints in response to this unilateral U.S. concession. The outbreak of COVID-19 in South Korea in 2020 led to the additional curtailment of training activity, raising the possibility that allied deterrence and defense capabilities could be further degraded. In March 2022, the U.S. conducted its first aircraft carrier exercise near Korea since 2018, and the Biden Administration appears likely to resume large-scale allied military exercises in South Korea.14

The ROK 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. In February 2019, South Korea agreed to increase its share of the cost by approximately 8 percent to $924 million. Later in 2019, President Trump demanded a fivefold increase of $5 billion a year and threatened to reduce or remove U.S. forces from South Korea. In April 2021, the Biden Administration signed an agreement accepting an incremental increase in Seoul’s contribution in line with previous agreements, thereby defusing tensions within the alliance.

South Korea spends 2.6 percent of its gross domestic product (GDP) on defense—more than is spent by any European ally. Seoul absorbs costs not covered in the cost-sharing agreement, including $10 billion, or 93 percent, of the cost of constructing Camp Humphreys, the largest U.S. base on foreign soil. During the past four years, South Korea has purchased $13 billion in arms from the United States.15

The Philippines. America’s oldest defense relationship in Asia is with the Philippines. The United States seized the Philippines from the Spanish more than a century ago as a result of the Spanish–American War and a subsequent conflict with indigenous Philippine nationalist forces. Unlike other colonial powers, however, the U.S. put in place a mechanism by which the Philippines could transition through a period as a commonwealth until receiving full independence in 1946. Just as important, substantial numbers of Filipinos fought alongside the United States against Japan in World War II, establishing a bond between the two peoples. Following World War II and after assisting the newly independent Filipino government against the Communist Hukbalahap movement in the 1940s, the United States and the Philippines signed a mutual defense treaty (MDT).

For much of the period between 1898 and the end of the Cold War, the largest American bases in the Pacific were in the Philippines, centered on the U.S. Navy base in Subic Bay and the complex of airfields that developed around Clark Field (later Clark Air Base). While the Philippines have never had the ability to provide substantial financial support for the American presence, the unparalleled base infrastructure provided replenishment and repair facilities and substantially extended deployment periods throughout the East Asian littoral.

These bases, being reminders of the colonial era, were often centers of controversy. In 1991, a successor to the Military Bases Agreement between the U.S. and the Philippines was submitted to the Philippine Senate for ratification. After a lengthy debate, the Philippines rejected the treaty, thereby compelling American withdrawal from Philippine bases. Given the effects of the 1991 eruption of Mount Pinatubo, which devastated Clark Air Base and damaged many Subic Bay facilities, and the end of the Cold War, it was not felt that closure of the bases would fundamentally damage America’s posture in the region.

Moreover, despite the closing of the American bases and consequent slashing of American military assistance, U.S.–Philippine military relations remained close, and assistance began to increase again after 9/11 as U.S. forces supported Philippine efforts to counter Islamic terrorist groups, including the Abu Sayyaf Group (ASG), in the South of the 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.

The U.S. presence in Mindanao continued at a reduced level until the Trump Administration, alarmed by the terrorist threat there, began Operation Pacific Eagle–Philippines (OPE–P). The presence of 200–300 American advisers proved very valuable to the Philippines in its 2017 battle against Islamist insurgents in Marawi.16

Continued on-the-ground military assistance for the counterterrorism challenge in Mindanao and other security cooperation in the Philippines received a boost in July 2021 when the Philippines, during a visit by American Secretary of Defense Lloyd Austin, retracted its intention to abrogate the 1998 U.S.–Philippines Visiting Forces Agreement (VFA). Since February 2020, the VFA has operated on serial six-month extensions offered by the Philippine President. An instrument of the MDT, the VFA specifies the procedures governing the deployment of U.S. forces and equipment to the Philippines. It also governs the application of domestic Philippine law to U.S. personnel, which is the most substantive part of the VFA and historically its most controversial.

The VFA undergirds approximately 280 U.S.–Philippine annual exercises—more than are conducted with any other military in Southeast Asia. Its abrogation would have slowed the rate of these interactions, conditioned their composition, and exposed each element of them to political pressures in the Philippines. Its preservation, on the other hand, not only sheds these constraints, but also enables the expansion of cooperation. The most recent example was the conduct of annual Balikatan exercises, billed by both sides as the largest ever held.17 The U.S. embassy reported deployment of “nearly 9,000” troops, “more than 50 aircraft, four ships, 10 amphibious craft, four HIMARS rocket system launchers, and four Patriot missile systems” as well as “approximately 40 personnel from the Australian Defense Force.”18 The U.S. and the Philippines have also resumed plans for base improvement and sharing arrangements under the 2014 U.S.–Philippine Enhanced Defense Cooperation Agreement (EDCA).19

The U.S. government has long made it clear that any attack on Philippine government ships or aircraft or on the Philippine armed forces—for example, by China—would be covered under the U.S.–Philippine mutual defense treaty.20 This makes it incumbent on the U.S., consistent with its constitutional procedures, to come to the defense of the Philippines. U.S. Secretary of State Antony Blinken reiterated this commitment in two separate calls with the Philippine Secretary of Foreign Affairs in January and April 2021.21 Secretary of Defense Austin made a similar statement in September, also reiterating the treaty’s application to the South China Sea, an issue that was once subject to some doubt.22

Thailand. The U.S.–Thai security relationship is built on the 1954 Manila Pact, which established the now-defunct SEATO, and the 1962 Thanat–Rusk agreement.23 These were supplemented by the Joint Vision Statements for the Thai–U.S. Defense Alliance of 2012 and 2020.24 In addition, Thailand gained improved access to American arms sales in 2003 when it was designated a “major, non-NATO ally.”

Thailand’s central location has made it an important part of the network of U.S. alliances in Asia. During the Vietnam War, American 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.

U.S. and Thai forces exercise together regularly, most notably in the annual Cobra Gold exercises, which were initiated in 1982. This builds on a partnership that began with the dispatch of Thai forces to the Korean War, during which Thailand lost more than 1,200 of the approximately 6,000 troops it had deployed. The Cobra Gold exercise is the world’s longest-running international military exercise25 and one of its largest. The most recent, in 2022, although again scaled back because of concern for the COVID pandemic, involved 1,200 American troops and 2,000 Thai troops26 as well as participants from a range of other countries, including India, Indonesia, Japan, South Korea, and Australia.27 For many years, a small number of Chinese personnel have also participated. Because of pandemic concerns, “[a]ctivities like live fire drills, amphibious landings and evacuation operations” were excluded.28

In contrast to the close relations between their militaries, U.S.–Thailand political relations have been strained since 2006. A coup that year and another in 2014 limited military-to-military relations for more than 10 years. This was due partly to standing U.S. law prohibiting assistance to governments that result from coups against democratically elected governments and partly to policy choices by the U.S. government.

The U.S. and Thailand, however, have managed to salvage much of their military-to-military cooperation and now look to normalize relations. This has been made possible by two developments: elections in 2019, which led to a new civilian government, and Washington’s new strategic focus on great-power competition with China. As a result, the U.S. accepted the flawed Thai electoral model as an opportunity to encourage the relationship. This encompassed high-level engagement and arms transfers to the Thai military of major systems like Stryker armored vehicles and Black Hawk helicopters. Under the Biden Administration, this trend may lead to the sale of the F-35.29

Over several decades, amid uncertainty in the U.S. commitment to the relationship, Thailand has been drifting geopolitically away from the U.S. and toward China. This process has been accelerating partly because of expanding economic relations between the two states and partly because of complications in U.S.–Thai relations arising from the political situation in Thailand and a general difference in threat perception concerning China. The U.S. considers China its greatest long-term security challenge; Thailand has no such concern.

Relations between the Thai and Chinese militaries have improved steadily over the years. Intelligence officers began formal meetings in 1988. Thai and Chinese 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 2015.30 The Thais conduct more bilateral exercises with the Chinese than are conducted by any other military in Southeast Asia.31

The Thais also have been buying Chinese military equipment for many years. Purchases in recent years have included significant buys of battle tanks and armored personnel carriers.32 According to the Stockholm International Peace Research Institute (SIPRI), from 2006–2021, China has been a significantly bigger supplier than the U.S.33 These deals, however, have not been without difficulty. Thailand’s 2017 acquisition of submarines, for example, has been stalled first by a combination of budget restraints, the priority of COVID-19 response, and public protest34 and more recently by Germany’s refusal to allow export of the engines the boats require.35 Submarines could be particularly critical to Sino–Thai relations because their attendant training and maintenance will require a greater Chinese military presence at Thai military facilities.

Australia. Australia is one of America’s most important allies in the Indo-Pacific. U.S.–Australia security ties date back to World War I when U.S. forces fought under Australian command on the Western Front in Europe, and they deepened during World War II when, after Japan commenced hostilities in the Western Pacific (and despite British promises), Australian forces committed to the North Africa campaign were not returned to defend the continent. As Japanese forces attacked the East Indies and secured Singapore, Australia turned to the United States to bolster 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 (most recently in August 2020) 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.36 Australia also has long granted the United States access to a number of 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,”37 and naval communications facilities on the North West Cape of Australia.38

In 2011, cooperation and U.S. access were expanded with the U.S. Force Posture Initiatives (USFPI), which included Marine Rotational Force–Darwin and Enhanced Air Cooperation. The rotation of up to 2,500 U.S. Marines for a set of six-month exercises near Darwin, Australia, began in 2012. The current rotation is comprised of 2,200 Marines39 and an Army detachment.40 In the past, these forces have deployed with assets including a tilt-rotor 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 under the initiative include “fifth generation integration, aircraft maintenance integration, aeromedical evacuation (AME) integration, refuelling certification, and combined technical skills and logistics training.”41 It has been accompanied by the buildout of related infrastructure at Australian bases and, of note most recently, a massive fuel storage facility in Darwin.42 Other improvements are underway at training areas and ranges in Australia’s Northern Territories.43

In 2021, the U.S., Australia, and the U.K., which already enjoyed close security cooperation, moved bilaterally and in the context of the Five Eyes intelligence-sharing arrangement to formalize and deepen these ties through the Australia–United Kingdom–United States partnership (AUKUS). This trilateral partnership is focused on current defense-related technology. Central to and most immediate among its stated priorities is support for Australia’s acquisition of “a conventionally armed, nuclear powered submarine capability at the earliest possible date, while upholding the highest nonproliferation standards.”44 The White House has reported either “strong progress” or “recently initiated work” in several areas beyond submarine technology, which is already underway. These areas include (among others) undersea robotic autonomous systems, quantum technologies, artificial intelligence, and hypersonic capabilities.45

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. These biannual exercises 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.46 COVID forced the 2021 iteration to downsize, but the 2019 version included more than 34,000 personnel from the U.S. and Australia.

Singapore. Singapore is America’s closest non-ally partner in the Western Pacific. The agreements that support this security relationship are the 2015 U.S.–Singapore Defense Cooperation Agreement (DCA), which is 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. Pursuant to these agreements and other understandings, Singapore hosts U.S. naval ships and aircraft as well as the principal logistics support node for the U.S. Seventh Fleet.

Singapore trains approximately 1,000 military personnel in the United States each year on such American-produced equipment as F-15SG and F-16C/D fighter aircraft and CH-47 Chinook and AH-64 Apache helicopters.47 Along with American allies Australia, Japan, and South Korea, Singapore also has ordered and been approved to buy the F-35.48 Like others of its assets, the F-35s will be housed at training facilities in the U.S.49 and perhaps on Guam under an agreement reached in 2019.50

New Zealand. For much of the Cold War, U.S. defense ties with New Zealand were similar to those between America and Australia. In 1986, however, as a result of controversies over U.S. Navy employment of nuclear power and the possible deployment of U.S. naval vessels with nuclear weapons, the U.S. suspended its obligations to New Zealand under the 1951 ANZUS Treaty.

Defense relations improved in the early 21st century as New Zealand committed forces to Afghanistan and dispatched an engineering detachment to Iraq. The 2010 Wellington Declaration and 2012 Washington Declaration, while not restoring full security ties, allowed the two nations to resume high-level defense dialogues.51 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, U.S. Secretary of Defense Chuck Hagel and New Zealand Defense Minister Jonathan Coleman announced the resumption of military-to-military cooperation, and in July 2016, the U.S. 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.52 At the time of the visit in November 2016, both sides claimed to have satisfied their respective legal requirements.53 The prime minister expressed confidence that the vessel was not nuclear-powered and did not possess nuclear armaments, and 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 ship visits by the U.S. Coast Guard, and in 2017, New Zealand lent the services of one 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. Another U.S. naval warship did not visit New Zealand until November 2021, when the guided-missile destroyer USS Howard made a port call.54

New Zealand is a member of the elite Five Eyes intelligence alliance with the U.S., Canada, Australia, and the U.K.55

Taiwan. When the United States shifted its recognition of the government of China from the Republic of China (on Taiwan) to the People’s Republic of China (PRC, the mainland), it also declared certain commitments concerning the security of Taiwan. These commitments are embodied in the Taiwan Relations Act (TRA) and the subsequent “Six Assurances.”

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.

Under the TRA, it is U.S. policy “to provide Taiwan with arms of a defensive character.”56 The TRA 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.”57 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 “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.”58 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.59

Supplementing the TRA are the “Six Assurances” issued by President Ronald Reagan in a secret July 1982 memo, 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 1982.60 These assurances 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. These assurances of July 14, 1982, were 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.61

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

The United States does not maintain any bases in Taiwan. However, in late 2021, after reports of an uptick in the number of U.S. military advisers in Taiwan, Taiwan’s President acknowledged their presence,62 going back at least to 2008.63 The numbers involved are in the dozens64 with most of these advisers involved in the provision of training on U.S.-sourced military equipment.

Vietnam, Malaysia, and Indonesia. On a region-wide basis, 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 is intended to improve the security capacity of U.S. partners, and the Pacific Deterrence Initiative (PDI) bolsters America’s military presence and makes it more accountable. Among the most important of the bilateral partnerships in this effort, beyond those listed above, are 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.

Since shortly after the normalization of diplomatic relations between the two countries in 1995, the U.S. and Vietnam also have gradually normalized their defense relationship. The relationship was codified in 2011 with a Memorandum of Understanding Advancing Bilateral Defense Cooperation. In 2015, the MOU was updated with the Joint Vision Statement on Defense Cooperation, which includes references to such issues as “defense technology exchange,”65 and was implemented under a three-year 2018–2020 Plan of Action for United States–Viet Nam Defense Cooperation that was agreed upon in 2017.66 According to USINDOPACOM’s 2022 command posture statement, the U.S. and Vietnam “are expected to issue a new Defense Cooperation Plan of Action for 2022–2024 and an updated Defense MOU Annex codifying new cooperation areas, including defense trade, pilot training, cyber, and personnel accounting (POW/MIA).”67

The most significant development with respect to security ties over the past several years has been relaxation of the 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; lifting it, however, has not changed the nature of the articles that are likely to be sold.

Transfers to date have been to the Vietnamese Coast Guard. These include provision under the Excess Defense Articles (EDA) program of two decommissioned Hamilton-class cutters, with a possible third on the way,68 and 24 Metal Shark patrol boats as well as infrastructure support.69 Vietnam is scheduled to take delivery of six unmanned Boeing-made Scan Eagle aerial vehicles (UAVs) for its Coast Guard.70 The U.S. is also providing T-6 turboprop trainer aircraft.71 Agreement has yet to be reached with respect to sales of bigger-ticket items like refurbished P-3 maritime patrol aircraft, although 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.72 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. It did not participate in the exercise in 2020, when it was scaled down because of COVID-19,73 or in 2022.

There have been two high-profile port calls to Vietnam since 2018. Early that year, the USS Carl Vinson visited Da Nang with its escort ships in the first port call by a U.S. aircraft carrier since the Vietnam War, and another carrier, USS Theodore Roosevelt, visited Da Nang in March 2020. 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.74

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, party-to-party ties between the Communist Parties of Vietnam and China, and a Vietnamese foreign policy that seeks to balance relationships with all major powers. 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.

The U.S. and Malaysia, despite occasional political differences, “have maintained steady defense cooperation since the 1990s.” Examples of this cooperation include Malaysian assistance in the reconstruction of Afghanistan and involvement in anti-piracy operations “near the Malacca Strait and…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.”75 The U.S. has occasionally flown P-3 and/or P-8 patrol aircraft out of Malaysian bases in Borneo.

The U.S. relationship with Malaysia was strengthened under President Barack Obama and continued on a positive trajectory under the Trump Administration. In addition to cooperation on counterterrorism, the U.S. 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.76

The upgrading of its F-18 fleet is the most significant U.S. defense program currently underway with Malaysia.77 Malaysia reportedly also “is hoping to buy Kuwait’s entire fleet of Boeing F/A-18 Hornet multi-role fighter jets, although discussions between both governments over the sale have yet to begin.”78

The U.S.–Indonesia defense relationship was revived in 2005 following a period of estrangement caused by American concerns about 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 U.S. has also worked closely with Indonesia’s defense establishment to reform Indonesia’s strategic defense planning processes.

U.S.–Indonesia military cooperation is governed by the 2010 Framework Arrangement on Cooperative Activities in the Field of Defense and the 2015 Joint Statement on Comprehensive Defense Cooperation79 as well as the 2010 Comprehensive Partnership. 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 [High Availability/Disaster Recovery]; and countering transnational threats such as terrorism and piracy.”80

In 2021, the agreements framed new progress in the relationship that included breaking ground on a new coast guard training base,81 inauguration of a new Strategic Dialogue,82 and the largest-ever U.S.–Indonesia army exercise.83 This exercise, Garuda Shield, involved a combined 4,500 troops. In a major 2022 development, the U.S. agreed to sell Indonesia up to 36 F-15s and related equipment and munitions worth $14 billion.84 As of March 2021, the U.S. “ha[d] $1.88 billion in active government-to-government sales cases with Indonesia under the Foreign Military Sales (FMS) system.”85

The U.S. 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 marked the beginning of Operation Enduring Freedom to combat al-Qaeda and its Taliban supporters. The U.S., in alliance with the U.K. and the 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 initiated an insurgency in Afghanistan in 2003.

In August 2003, NATO joined the war in Afghanistan and assumed control of the International Security Assistance Force (ISAF). In 2011, at the height of the war, there were 50 troop-contributing nations and nearly 150,000 NATO and U.S. forces on the ground in Afghanistan. On December 28, 2014, NATO formally ended combat operations and relinquished responsibility to the Afghan security forces, which numbered around 352,000 (including army and police).86

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. In February 2020, Ambassador Khalilzad and Taliban co-founder and chief negotiator Abdul Ghani Baradar signed a tentative peace agreement in which the Taliban agreed that it would not allow al-Qaeda or any other transnational terrorist group to use Afghan soil. It also agreed not to attack U.S. forces as long as they provided and remained committed to a withdrawal timeline, eventually set at May 2021.

In April 2021, President Joseph Biden announced that the U.S. would be withdrawing its remaining 2,500 soldiers from Afghanistan by September 11, 2021, remarking that America’s “reasons for remaining in Afghanistan are becoming increasingly unclear.”87 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, President Ghani fled the country for the United Arab Emirates (UAE), and the Afghan security forces largely abandoned their posts.88

Having left the air force base at Bagram in July, the U.S. and other countries were left trying to evacuate their citizens and allies from the Kabul International Airport as the Taliban assumed control of the capital. Amid the chaos, a suicide bombing attack on the airport perimeter on August 26 killed 13 U.S. military personnel and nearly 200 Afghans. IS-K, the local branch of ISIS, claimed responsibility for the attack, and the Biden Administration subsequently launched drone strikes on two IS-K targets.89 The last U.S. forces were withdrawn on August 30, 2021.

Early in September, the Taliban 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.90 Sirajuddin Haqqani, arguably the most powerful figure in the new Afghan government, carries a $10 million U.S. bounty. Since seizing power, the Taliban government has hunted down and executed hundreds of former government officials and members of the Afghan security forces. 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.

Like most of the world’s other governments, the U.S. government has refused to offer the new Taliban government diplomatic recognition. In October 2021, Under Secretary of Defense for Policy Colin Kahl admitted that both al-Qaeda and ISIS-K were operating in Afghanistan with the intent to conduct terrorist attacks abroad, including against the U.S. Specifically, Kahl estimated that “[w]e could see ISIS-K generate that capability in somewhere between 6 or 12 months” and that “Al Qaeda would take a year or two to reconstitute that capability.”91

Pakistan. During the early stages of the war in Afghanistan, the U.S. and NATO relied heavily on logistical supply lines running through Pakistan to resupply anti-Taliban coalition forces. Supplies and fuel were carried on transportation routes from the port at Karachi to Afghan–Pakistani border crossing points at Torkham in the Khyber Pass and Chaman in Baluchistan province. For roughly the first decade of the war, approximately 80 percent of U.S. and NATO supplies traveled through Pakistani territory. Those amounts progressively decreased as the U.S. and allied troop presence shrank.

By the late 2000s, tensions emerged in the relationship over accusations by U.S. analysts and officials 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 or “shura” was located in Quetta, the capital of Pakistan’s Baluchistan province. With relations already tense, 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. Relations deteriorated further in 2017 when President Donald 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.”92

Between 2001 and 2016, Pakistan received approximately $30 billion in aid and “reimbursements” from the U.S. in the form of coalition support funds (CSF) for its military deployments and operations along the border with Afghanistan. In 2016, reflecting the growing congressional resistance to military assistance for Pakistan, Congress blocked funds for the provision of eight F-16s. According to the Congressional Research Service, U.S. aid appropriations and military reimbursements have fallen continuously since fiscal year (FY) 2013; CSF reimbursements fell to zero in FY 2017 and remained at that level through FY 2020.93

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.94 In addition to suspending aid, the Trump Administration supported the addition of Pakistan to the Financial Action Task Force (FATF) “grey list” for failing to fulfill its obligations to prevent the financing of terrorism and its designation as a “Countr[y] of Particular Concern under the International Religious Freedom Act of 1998 for having engaged in or tolerated ‘systematic, ongoing, [and] egregious violations of religious freedom.”95 Pakistan remains on the grey list in 2022.

Despite harboring and supporting a variety of known terrorist groups that operate in Afghanistan and Kashmir, Pakistan has also been the victim of terrorism from anti-state extremist groups, including the Pakistani Taliban or 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.96 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.97

However, since the Afghan Taliban assumed power in Kabul, the number of attacks on Pakistan civilian and military targets has spiked dramatically98 with the TTP and the local affiliate of the Islamic State taking credit for most of these attacks. Islamabad has repeatedly accused the Taliban government in Kabul of harboring these groups 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 militant groups, causing dozens of civilian casualties in the process.99

Pakistan–U.S. relations improved modestly from 2018–2021 as Pakistan involved itself as a key player in bringing the Afghan Taliban to the negotiating table with the U.S. government. However, relations remained generally frosty and have improved little under the Biden Administration, with President Biden reportedly refusing to engage in direct communications with Prime Minister Imran Khan and Pakistan declining an invitation to attend President Biden’s December 2021 Summit for Democracy. 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: “We don’t see ourselves building a broad relationship with Pakistan. And we have no interest in returning to the days of hyphenated India–Pakistan.”100

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 to around 200 warheads by 2025, if the current trend continues.”101

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 increase.

Increased reliance on tactical nuclear weapons (TNWs) is of particular concern because launch authorities for TNWs are typically delegated to lower-tier field commanders far from the central authority in Islamabad. Another concern is the possibility 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, conversely, were to assume that they were under Pakistani government control after they ceased to be.

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. Pakistan’s weapons-grade materials were ranked the 19th least secure by the Nuclear Threat Initiative (NTI) in 2018, with only Iran’s and North Korea’s ranking less secure at 21st and 22nd, respectively.102 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.”103

There is the additional (though less likely) scenario of extremists gaining access through a collapse of the state. While 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 unlikely. The country’s most powerful institution, the 550,000-strong army that has ruled Pakistan for almost half of its existence, would almost certainly intervene and assume control once again 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 plausible.

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 commonplace.

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 all-out 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. In early 2019, Pakistan conducted several tests of its nuclear-capable, short-range NASR ballistic missiles.104

The military and strategic dynamic between India and Pakistan has grown more volatile since the May 2014 election of Bharatiya Janata Party (BJP) leader Narendra Modi as India’s prime minister. Modi invited Pakistani Prime Minister Nawaz Sharif to his swearing-in ceremony, but in August 2014, the two sides engaged in intense firing and shelling along their international border and the Line of Control that divides Kashmir. A similar escalation in border tensions occurred again in October 2014 when a series of firing incidents claimed more than a dozen casualties with several dozen more injured.105

On December 25, 2015, Modi made an impromptu visit to Lahore—the first visit to Pakistan by an Indian leader in 12 years—to meet with Sharif. The visit created enormous goodwill between the two countries and raised hope that official dialogue would soon resume. Again, however, violence marred the new opening. One week after the meeting, militants attacked an Indian airbase at Pathankot, killing seven Indian security personnel.106

A comprehensive India–Pakistan dialogue has remained frozen ever since, although the two governments still regularly communicate with one another. New Delhi has insisted 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. Unfortunately, the past few years have been marred by additional terrorist attacks and cross-border shelling.

The Pakistan-based Jaish-e-Mohammed (JeM) terrorist group was responsible for a January 2, 2016, attack on the Indian airbase at Pathankot, 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 1989.107

Following a deadly attack on Indian security forces in Pulwama, Kashmir, in February 2019, 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.108 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. Nevertheless, both militaries continued to engage in artillery attacks along the disputed border throughout 2019. Pakistan reported more than 45 casualties, including 14 soldiers, from Indian shelling between January 2019 and October 2019. India reported 21 casualties and over 2,000 cease-fire violations during the same period.109

Skirmishes at the LoC continued and even accelerated in 2020 with India’s Home Ministry registering “5,133 instances of ceasefire violations along the Line of Control (LoC) with Pakistan last year, which resulted in 46 fatalities.”110 In early 2021, however, India and Pakistan experienced at least a partial diplomatic thaw as both countries combated the COVID-19 global pandemic. In February, both countries agreed to observe a strict cease-fire along the LOC,111 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.”112

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.”113 Pakistan called the launch irresponsible and demanded a “joint probe to accurately establish the facts” in a response that one correspondent characterized as “measured.”114

India. During the Cold War, U.S.–Indian 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 of 1965. The relationship was largely characterized by mistrust in the 1970s under the Nixon Administration. America’s ties with India hit a nadir during the Third Indo–Pakistan war of 1971 when the U.S. 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 Moscow. 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 U.S. and India have improved significantly over the past two decades (particularly since the signing of a 10-year defense partnership and civil nuclear deal in 2005) as 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.”115 The U.S. has supplied India 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, and Firefinder radar. The two countries also have several information-sharing and intelligence-sharing agreements in place, including one that covers “white” or commercial shipping in the Indian Ocean.

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 the Logistics Exchange Memorandum of Agreement (LEMOA), which 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. Since then, Indian and U.S. warships have begun to offer each other refueling and resupply services at sea.116 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.

America’s strategic and defense ties with India advanced in several important ways during the Trump Administration. In 2018, India was granted STA-1 status, easing controls on exports of advanced defense technology. India is only 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. In 2020, the U.S. and India signed the Basic Exchange Cooperation Agreement (BECA), which creates a framework for the sharing of geospatial intelligence.

Beyond these “foundational” or “enabling” military agreements, in recent years, the two countries have also 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. During the Trump Administration, the two countries also 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) in 2017.117 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. 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.

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-ever tri-service military exercise, nicknamed “Tiger Triumph.”

At the April 2022 2+2 defense and foreign policy dialogue, which was held in Washington, the two sides signed “a Space Situational Awareness arrangement” and “agreed to launch an inaugural Defense Artificial Intelligence Dialogue.” 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.”118 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.”119

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 local militaries aspire; instead, the region is characterized by a wide range of capabilities that are influenced by local threat perceptions, institutional interests, physical conditions, historical factors, and budgetary considerations.

Moreover, most Asian militaries have limited combat experience, particularly in high-intensity air or naval combat. Some, like Malaysia, have never 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 doctrine will meet the exigencies of wartime realities.

Based on examinations of equipment, however, we assess that several Asian allies and friends have substantial potential military capabilities that are 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-15s in the Japan Air Self Defense Force and ROK Air Force; 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 and purchase 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, for example, field more tanks, principal surface combatants, and combat-capable aircraft than their British counterparts field. Similarly, South Korea fields more tanks, principal surface combatants, and combat-capable aircraft than Germany fields.

Both the ROK 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. It is also pursuing an indigenous missile defense capability.

As for Japan, its Aegis-class destroyers are equipped with SM-3 missiles, and it decided in 2017 to install the Aegis Ashore missile defense system to supplement its Patriot missile batteries.120 In June 2020, Tokyo unexpectedly cancelled plans to build two Aegis Ashore missile defense sites, citing the potential for the interceptor missile’s first-stage booster to fall onto populated areas. Other likely factors in the decision include the overall cost of the program, inept handling of the site-selection process, and government unwillingness to press national objectives over local resistance.121 Currently, Tokyo plans to build an additional two Aegis-capable ships to compensate for the cancellation of the Aegis Ashore project.

Australia also has very capable armed forces. They 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. Australia’s military has several operations underway in the region from the Southwest Pacific islands, which are so critically important to it, to its partnership with Malaysia in the North Indian Ocean and South China Sea, to the Korean Peninsula.122

Singapore’s small population and physical borders limit the size of its military, but in terms of equipment and training, it has Southeast Asia’s largest defense budget123 and fields some of the region’s highest-quality forces. Singapore’s 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)124 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 a squadron of KC-130 tankers that can help to extend range or time on station.125 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 2026.126

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 1.0 percent of GDP on its military in 2020.127 The most modern ships in the Philippine navy are three former U.S. Hamilton-class Coast Guard cutters. It has also taken delivery of new South Korean–built frigates and is set to buy two more smaller South Korean naval vessels.128 The Philippines also has purchased 12 light attack fighter aircraft from South Korea129 and has been cleared to acquire 12 new American F-16s.130

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 2,900 personnel in the region.131 It also conducts multiple naval deployments each year out of Metropolitan France. The U.K. is likewise very 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.

Current U.S. Presence in Asia

U.S. Indo-Pacific Command. Established in 1947 as U.S. Pacific Command (PACOM), 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.132

USINDOPACOM’s area of responsibility (AOR) includes not only the expanses of the Pacific, but also Alaska and portions of the Arctic, South Asia, and the Indian Ocean. Its 36 nations represent more than 50 percent of the world’s population and include two of the three largest economies and nine of the 10 smallest; the most populous nation (China); the largest democracy (India); the largest Muslim-majority nation (Indonesia); and the world’s smallest republic (Nauru). The region is a vital driver of the global economy and includes the world’s busiest international sea-lanes and nine of its 10 largest ports. 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.”133

INDOPACOM has several “component and sub-unified commands”134 that include:

• U.S. Army Pacific. USARPAC is the Army’s component command in the Pacific. Headquartered in Hawaii and with approximately 80,000 soldiers, it supplies Army forces as necessary for various global contingencies and “has sent peacekeeping forces to the Sinai Peninsula, Haiti, East Timor and Bosnia.”135 Among its 12 subordinate commands are U.S. Army Japan, the 500th Military Intelligence Brigade, and U.S. Army Alaska.
• U.S. Pacific Air Force. PACAF is responsible for planning and conducting defensive and offensive air operations in the Asia–Pacific region. It has three numbered air forces under its command: 5th Air Force in Japan; 7th Air Force in Korea; and 11th Air Force, headquartered in Alaska. These air forces field two squadrons of F-15s, two squadrons of F-22s, five squadrons of F-16s, and a single squadron of A-10 ground attack aircraft as well as two squadrons of E-3 early-warning aircraft, tankers, and transports. Other forces that regularly come under PACAF command include B-52, B-1, and B-2 bombers. In 2020, PACAF activated two F-35A squadrons at Eielson Air Force Base in Alaska. It completed the integration of 54 “combat-coded” F-35A aircraft in April 2022, increasing the number of squadrons to four.136
• U.S. Pacific Fleet. PACFLT normally controls all U.S. naval forces committed to the Pacific, which usually represents 60 percent of the Navy’s fleet. It is organized into Seventh Fleet, headquartered in Japan, and Third Fleet, headquartered in California. Seventh Fleet comprises the forward-deployed element of PACFLT and includes 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. The Third Fleet’s AOR spans the West Coast of the United States to the International Date Line and includes the Alaskan coastline and parts of the Arctic. In recent years, the involvement of the Third Fleet’s five carrier strike groups in the Western Pacific has been eased by the blurring of this boundary between the two fleets’ areas of operation under a concept called “Third Fleet Forward.” Beginning in 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 as a result of several well-publicized operations in the South China Sea. Under the Trump Administration, the frequency of these operations increased significantly.
• U.S. Marine Forces Pacific. With its headquarters in Hawaii, MARFORPAC controls elements of the U.S. Marine Corps operating in the Asia–Pacific region. Because of its extensive responsibilities and physical span, MARFORPAC controls two-thirds of Marine Corps forces: the I Marine Expeditionary Force (MEF), centered on the 1st Marine Division, 3rd Marine Air Wing, and 1st Marine Logistics Group, and the III Marine Expeditionary Force, centered on the 3rd Marine Division, 1st Marine Air Wing, and 3rd Marine Logistics Group. The I MEF is headquartered at Camp Pendleton, California, and the III MEF is headquartered on Okinawa, although each has various subordinate elements deployed at any time throughout the Pacific on exercises, to maintain presence, or engaged in other activities. MARFORPAC is responsible for supporting three different commands: It is the U.S. Marine Corps component of USINDOPACOM, provides the Fleet Marine Forces to PACFLT, and provides Marine forces for U.S. Forces Korea (USFK).
• U.S. Special Operations Command Pacific. SOCPAC has operational control of various special operations forces, including 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. It supports the Pacific Command’s Theater Security Cooperation Program as well as other plans and contingency responses. SOCPAC forces also support various operations in the region other than warfighting, such as counterdrug operations, counterterrorism training, humanitarian assistance, and demining activities.
• U.S. Forces Korea and U.S. Eighth Army. Because of the unique situation on the Korean Peninsula, two subcomponents of USINDOPACOM—U.S. Forces Korea (USFK) and U.S. Eighth Army—are based in Korea. USFK, a joint headquarters led by a four-star U.S. general, is in charge of the various U.S. military elements on the peninsula. U.S. Eighth Army operates in conjunction with USFK as well as with the United Nations presence in the form of United Nations Command.

Other forces, including space capabilities, cyber capabilities, air and sealift assets, and additional combat forces, may be made available to USINDOPACOM depending on requirements and availability.

Key Infrastructure That Enables Expeditionary Warfighting Capabilities

Any planning for operations in the Pacific will be dominated by the “tyranny of distance.” Because of the extensive distances that must be traversed in order to deploy forces, even Air Force units will take one or more days to deploy, and ships measure steaming time in weeks. For instance, a ship sailing at 20 knots 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—if ships encounter no interference along the journey.137

China’s growing anti-access/area denial (A2/AD) capabilities, ranging 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 not only jeopardize American combat forces that would flow into the theater for initial combat, but also would continue to threaten the logistical support needed to sustain American combat power during the subsequent 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. The Marine Corps is working to expand a major facility, Marine Corps Base Camp Blaz, activated on October 1, 2020.138 Upon completion in 2025, the base will host 5,000 Marines comprising various aviation and ground combat, combat support, logistics, and headquarters units.139 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 2005.140 These improvements have been accelerated and expanded even as China’s A2/AD capabilities have raised doubts about the ability of the U.S. to sustain operations in the Asian littoral. The concentration of air and naval assets as well as logistical infrastructure, however, makes the island an attractive potential target in the event of conflict. The increasing reach of Chinese and North Korean ballistic missiles reflects this growing vulnerability.

Guam and 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 the areas. U.S. Navy units on Guam and in Saipan, Commonwealth of the Northern Marianas, support prepositioning ships that can supply Army or Marine Corps units deployed for contingency operations in Asia.

Allied and Other Friendly Facilities

For the United States, access to bases in Asia has long been a vital part of its ability to support military operations in the region. 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 region. 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.

Japan. In Japan, the United States has access to more than 100 different facilities, including communications stations, military and dependent housing, fuel and ammunition depots, and weapons and training ranges in addition to such major bases as the air bases at Misawa, Yokota, and Kadena and naval facilities at Yokosuka, Atsugi, and Sasebo. The naval facilities support the USS Ronald Reagan carrier strike group (CSG), which is home-ported in Yokosuka, and a Navy-Marine Expeditionary Strike Group (ESG) centered on the USS America, home-ported at Sasebo. The skilled workforce at places like Yokosuka is needed to maintain American forces and repair equipment in time of conflict. Replacing them would take years if not decades.

This combination of facilities and workforce, in addition to physical location and political support, makes Japan an essential part of any American military response to contingencies in the Western Pacific. Japanese financial support for the American presence also makes these facilities some of the most cost-effective in the world.

The status of one critical U.S. base has been a matter of public debate in Japan for many years. The U.S. Marine Corps’ Third Marine Expeditionary Force, based on Okinawa, is the U.S. rapid reaction force in the Pacific. The Marine Air-Ground Task Force, comprised of air, ground, and logistics elements, enables quick and effective response to crises or humanitarian disasters. To improve the political sustainability of U.S. forces by reducing the impact on the local population in that densely populated area, the Marines are relocating some units to Guam and less-populated areas of Okinawa. The latter includes moving a helicopter unit from Futenma to a new facility in a more remote location in northeastern Okinawa. Because of local resistance, construction of the Futenma Replacement Facility at Camp Schwab will not be complete until at least 2025, but the U.S. and Japanese governments have affirmed their support for the project.

South Korea. The United States also maintains an array of facilities in South Korea. The Army’s footprint in South Korea is larger than its footprint in Japan because the United States and South Korea remain focused on deterring North Korean aggression and preparing for any possible North Korean contingencies. The Army maintains four major facilities (which in turn control a number of smaller sites) at Daegu, Yongsan in Seoul, and Camps Red Cloud/Casey and Humphreys. These facilities support the U.S. 2nd Infantry Division, which is based in South Korea. Other key facilities include air bases at Osan and Kunsan and a naval facility at Chinhae near Pusan.

The Philippines. In 1992, the United States ended a nearly century-long presence in the Philippines when it withdrew from its base in Subic Bay as the base’s lease ended. The eruption of Mount Pinatubo had already forced the closure of Clark Air Base; the costs of repairing the facility were deemed too high to be worthwhile. In 2014, however, spurred by China’s growing assertiveness in the South China Sea, including against Philippine claims such as Mischief Reef (seized in 1995) and Scarborough Shoal (2012), the U.S. and the Philippines negotiated the Enhanced Defense Cooperation Agreement, which allowed for the rotation of American forces through Philippine military bases.

In 2016, the two sides agreed on an initial list of five bases to be used in the Philippines. Geographically distributed across the country, they are Antonio Bautista Air Base in Palawaan, closest to the Spratlys; Basa Air Base, located on the main Philippine island of Luzon and closest to the hotly contested Scarborough Shoal; Fort Magsaysay, also on Luzon and the only facility on the list that is not an air base; Lumbia Air Base in Mindanao, where Manila remains engaged in low-intensity combat with Islamist insurgents; and Mactan-Benito Ebuen Air Base in the central Philippines.141 In 2018, construction was completed on a humanitarian assistance and disaster relief warehouse located at Basa Air Base.142 American F-16s based in South Korea deployed there for a 12-day exercise with Philippine fighter jets in 2019143 and exercised there again in 2020.144 With the resolution of disputes over the status of America’s Visiting Forces Agreement with the Philippines, it is expected that building out of the other EDCA sites will begin as well.

It remains unclear precisely which additional forces would be rotated through the Philippines as a part of this agreement, which in turn affects the kinds of facilities that would be most needed. The base upgrades and deployments pursuant to the EDCA are part of a broader expansion of U.S.–Philippine defense ties begun under the Aquino government and continued under President Duterte with some adjustments.

Singapore. The United States does not have bases in Singapore, but it is allowed access to several key facilities that provide essential support for American forward presence. Since the closure of its facilities at Subic Bay, the United States has been allowed to operate the principal logistics command for the Seventh Fleet out of the Port of Singapore Authority’s Sembawang Terminal. The U.S. Navy also has access to Changi Naval Base, one of the few docks in the world that can handle a 100,000-ton American aircraft carrier. A small U.S. Air Force contingent operates out of Paya Lebar Air Base to support U.S. Air Force combat units visiting Singapore and Southeast Asia, and Singapore hosts Littoral Combat Ships (LCS) and rotating P-8 aircraft.145

Australia. The most prominent element of the U.S. presence in Australia is the deployment of U.S. Marines to Darwin in northern Australia. In keeping with Australian sensitivities about permanent American bases on Australian soil, however, the Marines do not maintain a permanent presence in the country.146 Similarly, the United States jointly staffs the Joint Defence Facility Pine Gap and the Joint Geological and Geophysical Research Station at Alice Springs and has access to the Harold E. Holt Naval Communication Station, including its space surveillance radar system, in the western part of the country.147

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).”148 Specifically, “MPF ships deliver a forward presence and rapid crisis response capability by pre-positioning equipment and supplies to various locations at sea.”149 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.

Conclusion

The Asian strategic environment is extremely expansive. It includes half the globe and is characterized by a variety of political relationships among states that possess wildly varying capabilities. The region includes long-standing American allies with relationships dating back to the beginning of the Cold War as well as recently established states and some long-standing adversaries such as North Korea.

American conceptions of the region must therefore recognize the physical limitations imposed by the tyranny of distance. Moving forces within the region (never mind to it) will take time and require extensive strategic lift assets as well as sufficient infrastructure (such as sea and aerial ports of debarkation that can handle American strategic lift assets) and political support. At the same time, the complicated nature of intra-Asian relations, especially unresolved historical and territorial issues, means that the United States, unlike Europe, cannot necessarily count on support from all of its regional allies in responding to any given contingency.

Scoring the Asia Operating Environment

As with the operating environments of Europe and the Middle East, 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 for military operations 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 in the region 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 the ability of the United States to respond to crises and, presumably, achieve successes 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 operations from, 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.150

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

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

Aggregating to a regional score of: Favorable