Assessing Threats to U.S. Vital Interests


Nov 17, 2020 19 min read

The Heritage Foundation

James Phillips

The threat to the American homeland emanating from Afghanistan and Pakistan is diverse, complex, and mostly indirect, largely involving non-state actors. The intentions of non-state terrorist groups like the TTP (Pakistani Taliban), al-Qaeda, and ISIS toward the U.S. are demonstrably hostile. Despite the broad and deep U.S. relationships with Pakistan’s governing elites and military, it is likely that the political–military interplay in Pakistan and instability in Afghanistan will continue to result in an active threat to the American homeland.

In addition, ongoing tensions between nuclear-armed rivals India and Pakistan could lead eventually to broader military conflict with some prospect of escalating to a nuclear exchange. Because neither side desires another general war, both countries have limited objectives and have demonstrated a desire to avoid escalation. However, the likelihood of miscalculation and escalation has grown considerably since 2016 when India ended its policy of not responding with force to Pakistani-backed terrorist attacks.

Afghanistan War. 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 eliminate the threat from al-Qaeda and topple the Taliban government that harbored the terrorist group. The U.S., in alliance with the United Kingdom and the anti-Taliban Afghan Northern Alliance forces, ousted the Taliban from power in December 2001. Many 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). At the height of the war in 2011, there were 50 troop-contributing nations, and nearly 150,000 NATO and U.S. forces were 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).1 After Afghan President Ashraf Ghani signed a bilateral security agreement with the U.S. and a Status of Forces Agreement with NATO, the international coalition launched Operation Resolute Support to train and support Afghan security forces.

In August 2017, while declining to announce specific troop levels, President Donald Trump recommitted America to the effort in Afghanistan and announced that “[c]onditions on the ground—not arbitrary timetables—will guide our strategy from now on.”2 He also suggested that his Administration would pursue a negotiated settlement with the Taliban. This was followed in 2018 by the initiation of direct talks with the Taliban in Doha, Qatar, in an attempt to find a political solution to the fighting.

In February 2020, after nearly two years of on-again, off-again negotiations, U.S. Special Envoy Zalmay Khalilzad and Taliban co-founder and chief negotiator Abdul Ghani Baradar signed a phase-one peace agreement in Doha. Among other things, the deal (the details of which can be found in the chapter in the Asia operating environment) is designed to bring the Taliban and the Afghan government to the negotiating table while allowing all U.S. and international troops to leave Afghanistan by the spring of 2021. As part of the agreement, the Taliban pledged to break ties with al-Qaeda and other transnational terrorist groups.

The agreement still faces many obstacles. Levels of violence and the number of attacks between U.S. forces and the Taliban have declined significantly since the signing of the agreement in February 2020. However, the Taliban has continued to engage in attacks on Afghan security forces, and that is likely to remain the case until intra-Afghan negotiations produce some form of peace agreement. The COVID-19 global pandemic has temporarily halted intra-Afghan talks, and there are no publicly available details on how the international community intends to enforce the Taliban’s commitment to renounce transnational terrorism.

Threats to the Homeland

Terrorist Groups Operating in Afghanistan and Pakistan (AfPak). This is a deadly region. In 2017, General John Nicholson, commander of the NATO-led Resolute Support Mission and of U.S. Forces Afghanistan, stated that the AfPak region harbors 20 of the “98 U.S.-designated terrorist groups globally,” the “highest concentration of terrorist groups anywhere in the world.”3

A wide variety of Islamist fundamentalist terrorist groups continue to operate from Pakistani territory, many with the support or sanction of the Pakistani state. Some continue to pose a direct threat to the U.S. homeland. Many are focused on launching attacks in Afghanistan, Kashmir, or other parts of India. Some target non-Muslims and Muslim minorities deemed un-Islamic inside Pakistan; others have targeted the Pakistani state and security forces. The threat posed by al-Qaeda in Pakistan has been gradually degraded by the killing of Osama bin Laden at his hideout in Abbottabad, Pakistan, in May 2011; by an intensive drone campaign in Pakistan’s tribal areas; and by Pakistani security forces. Nevertheless, al-Qaeda’s residual presence and the emergence of ISIS in neighboring Afghanistan remain serious concerns.

Efforts by ISIS to make inroads into Pakistan and Afghanistan, known as the so-called Islamic State-Khorasan (IS-K) have met with only limited success, most likely because of other terrorist groups’ well-established roots in the region. The Afghan Taliban views IS-K as a direct competitor for financial resources, recruits, and ideological influence. This competition was evident in a June 16, 2015, letter sent by the Taliban to then-ISIS leader Abu Bakr al-Baghdadi, urging his group not to take actions that could lead to “division of the Mujahideen’s command.”4 The Taliban has attacked IS-K on numerous occasions. For example, U.S. officials acknowledge that even though they were not coordinating directly, it was U.S. air strikes and Taliban ground attacks that caused IS-K to lose its stronghold in Afghanistan’s Nangarhar province.5

Reports of an ISIS presence in Afghanistan first began to surface in 2014, and the group has slowly gained a small foothold in the country. Though its actual numbers remain modest, its high-profile, high-casualty terrorist attacks have helped it to attract followers. In March 2019, General Joseph Votel, then commander of U.S. Central Command, said that he believed “ISIS Khorasan does have ideations focused on external operations toward our homeland.”6

The lack of publicly available information and the willingness of local fighters in the region to change allegiances with little thought make it next to impossible to determine the exact number of IS-K fighters in Afghanistan at any given time. A report issued by the United Nations Security Council in February 2019 claimed that ISIS had between 2,500 and 4,000 fighters in Afghanistan.7 In September 2019, U.S. officials estimated that there were between 2,000 and 5,000 ISIS fighters in Afghanistan.8 IS-K suffered a series of major defeats in 2019 that led to its “collapse” in eastern Afghanistan according to U.S. officials.9 Strikes by U.S. and Taliban forces appear to have diminished the Islamic State’s capabilities in late 2019, and in November, Afghan President Ghani claimed that ISIS had been “obliterated.”10

Experts believe that there is little coordination between the IS branch operating in Afghanistan and the central command structure of the group located in the Middle East. Instead, it draws recruits from disaffected members of the Pakistani Taliban and other radicalized Afghans and has frequently found itself at odds with the Afghan Taliban, with which it competes for resources, territory, and recruits. IS-K could benefit from Taliban fighters disgruntled by the peace deal with the U.S. and commitment to intra-Afghan talks. Also, IS-K is trying to be a spoiler in the peace process by conducting very high-profile and lethal attacks in Afghanistan, hoping that the international community will blame the Taliban.

Pakistan’s continued support for terrorist groups that have links to al-Qaeda, the Taliban, and the Haqqani Network undermines U.S. counterterrorism goals in the region. Pakistan’s military and intelligence leaders maintain a short-term tactical approach that involves fighting some terrorist groups that are deemed to be a threat to the state while supporting others that are aligned with Pakistan’s goal of extending its influence and curbing India’s.

In 2015, after a series of terrorist attacks against the Pakistani state and security services, the Pakistani government introduced a National Action Plan (NAP) to reinvigorate the country’s fight against terrorism. Implementation of the NAP and the Pakistani military’s operations against TTP (Pakistani Taliban) hideouts in North Waziristan helped to reduce Pakistan’s internal terrorist threat to some degree. According to the India-based South Asia Terrorism Portal, total fatalities in Pakistan (including terrorists/insurgents) have been declining steadily since 2009, when they peaked at 11,704. Since then, they have fallen to 5,496 in 2014, 1,803 in 2016, 1,260 in 2017, 691 in 2018, and 228 as of June 23, 2019.11

However, there are few signs that Pakistan’s crackdown on terrorism extends to groups that target India, such as the Lashkar-e-Taiba (LeT), which was responsible for the 2008 Mumbai attacks, and the Jaish-e-Mohammed (JeM), which carried out an attack on the Indian parliament in 2001, another on the airbase at Pathankot in 2016, and the deadliest attack on Indian security forces in Kashmir in February 2019.12

Threat of Regional War

Pakistan’s Nuclear Weapons Stockpile. In its most recent report on the topic, published in September 2018, the Bulletin of the Atomic Scientists estimated that Pakistan “has a nuclear weapons stockpile of 140 to 150 warheads” that could “realistically grow to 220 to 250 warheads by 2025, if the current trend continues.”13 As of July 2019, the Arms Control Association estimated that Pakistan had “150–160 nuclear warheads.”14 The possibility that terrorists could gain effective access to Pakistani nuclear weapons is contingent on a complex chain of circumstances, but its possible consequences make this the most dangerous regional threat scenario. Concern about the safety and security of Pakistan’s nuclear weapons increases when India–Pakistan tensions increase. During the 1999 Kargil crisis, for example, U.S. intelligence indicated that Pakistan had made “nuclear preparations,” and this spurred greater U.S. diplomatic involvement in defusing the crisis.15

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 would 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 so.

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 half-mile of Pakistan’s premier defense academy has fueled concern that al-Qaeda can operate relatively freely in parts of Pakistan and eventually might gain access to Pakistan’s nuclear arsenal. The Nuclear Threat Initiative’s Nuclear Security Index ranks 22 countries that possess “weapons-usable nuclear materials” for their susceptibility to theft. Pakistan’s weapons-grade materials were ranked the 20th least secure in 2018, with only Iran (21st) and North Korea (22nd) ranking lower.16

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, it is unlikely that the Pakistani state will collapse altogether. 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.17

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 in Kashmir, a disputed territory claimed in full by both India and Pakistan, are commonplace.

Another India–Pakistan conflict would jeopardize multiple U.S. interests in the region and could increase the threat of global terrorism if Pakistan were destabilized. Pakistan would rely on militant non-state actors to help it fight India, thereby creating a more permissive environment in which various terrorist groups could operate freely. The potential for a nuclear conflict would threaten U.S. businesses in the region and disrupt investment and trade flows, mainly between the U.S. and India, whose bilateral trade in goods and services reached roughly $150 billion in 2019. A conflict would also strain America’s ties with one or both of the combatants at a time when Pakistan–U.S. ties are already under severe stress and America is trying to build a stronger partnership with India. The effects of an actual nuclear exchange—both the human lives lost and the long-term economic damage—would be devastating.

India and Pakistan are engaged in a nuclear competition that threatens stability throughout the subcontinent. Both countries tested nuclear weapons in 1998, establishing themselves as overtly nuclear weapons states, although India first conducted a “peaceful” nuclear weapons test in 1974. Both countries also are developing naval nuclear weapons and already possess ballistic missile and aircraft-delivery platforms.18

As noted, it is estimated that Pakistan has a stockpile of 150–160 nuclear warheads. It also “has lowered the threshold for nuclear weapons use by developing tactical nuclear weapons capabilities to counter perceived Indian conventional military threats.”19 This in turn affects India’s nuclear use threshold and could affect those of China and other countries as well.

The broader 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 then, to express anger over a Pakistani official’s meeting with Kashmiri separatist leaders, later called off foreign secretary–level talks that were scheduled for August 2014. During the same month, the two sides engaged in intense firing and shelling along their international border (called the working boundary) and across 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.20

A meeting finally occurred on December 25, 2015, when 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. Six days after the meeting, militants attacked an Indian airbase at Pathankot, killing seven Indian security personnel.21

As a result, official India–Pakistan dialogue remains deadlocked even though the two sides are reportedly communicating quietly through their foreign secretaries and national security advisers. With Prime Minister Modi’s BJP sweeping national elections in May 2019 and earning him a second term in office, few expect any major breakthroughs in the near term. As noted, Pakistan continues to harbor terrorist groups like Lashkar-e-Taiba and Jaish-e-Mohammed. The latter 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 1989.22

Hafez Muhammed Saeed, LeT’s founder and the leader of its front organization Jamaat-ud-Dawa (JuD), has periodically been placed under arrest, only later to be released. He was arrested most recently in July 2019 and remains under house arrest, his trial on charges of financing terrorism having been delayed as a result of the COVID-19 pandemic.23 Previously, he had operated freely in Pakistan, often holding press conferences and inciting violence against India during large public rallies.

Some observers remain concerned about the possible impact of an international troop drawdown in Afghanistan. Such a drawdown could enable the Taliban and other extremist groups to strengthen their grip in the region, further undermining stability in Kashmir and raising the chances of another major terrorist attack against India. A successful future attack on Indian interests in Afghanistan along the lines of the bombing of the Indian embassy in Kabul in 2008 would sharpen tensions between New Delhi and Islamabad.

With terrorist groups operating relatively freely in Pakistan and maintaining links to the country’s 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.24

Pakistan’s nuclear weapons capability appears to have acted as a deterrent against Indian military escalation, both during the 2001–2002 military crisis and following the 2008 Mumbai attacks, but the Indian government has been under growing pressure to react strongly to terrorist provocations. In 2016, following an attack on an Indian army base in Uri, Kashmir, that killed 19 Indian soldiers, the Indian military reportedly launched surgical strikes on terrorist targets across the Line of Control in Pakistan-administered Kashmir. The Indian press indicated that up to 80 Indian commandos crossed the Line of Control on foot and destroyed seven “terror launch pads,” with attack helicopters on standby.25

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 Line of Control and dropped ordnance inside Pakistan proper (as opposed to disputed Kashmir), targeting several JeM training camps in Khyuber Pakhtunkhwa province.26 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 Line of Control 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 in the same period.27


In the AfPak region, non-state terrorist groups pose the greatest threat to the U.S. homeland. Pakistan represents a paradox: It is both a security partner and a security challenge. Islamabad provides a home and support to terrorist groups that are hostile to the U.S., to other U.S. partners in South Asia like India, and to the government in Afghanistan, which is particularly vulnerable to destabilization efforts. Both Pakistan and Afghanistan are already among the world’s most unstable states, and the instability of the former, given its nuclear arsenal, has a direct bearing on U.S. security.

This Index therefore assesses the overall threat from AfPak-based actors to the U.S. homeland as “testing” for level of provocation of behavior and “capable” for level of capability.

2021_IndexOfUSMilitaryStrength_ASSESSMENTS_Threats_AF-PAK_1.jpgDownload Assessment


  1. U.S. Department of Defense, Enhancing Security and Stability in Afghanistan, December 2016, p. 33, (accessed June 11, 2020).
  2. “Remarks by President Trump on the Strategy in Afghanistan and South Asia,” Fort Myer, Arlington, Virginia, August 21, 2017, (accessed June 11, 2020).
  3. Transcript, “Department of Defense Press Briefing by General Nicholson in the Pentagon Briefing Room,” U.S. Department of Defense, December 2, 2016, (accessed June 11, 2020). See also General John W. Nicholson, Commander, U.S. Forces–Afghanistan, statement on “The Situation in Afghanistan” before the Committee on Armed Services, U.S. Senate, February 9, 2017, p. 1, (accessed June 11, 2020).
  4. Sudarsan Raghavan, “Taliban in Afghanistan Tells Islamic State to Stay out of Country,” The Washington Post, June 16, 2015, (accessed June 11, 2020). See also Mirwais Harooni and Kay Johnson, “Taliban Urge Islamic State to Stop ‘Interference’ in Afghanistan,” Reuters, June 16, 2015, (accessed June 11, 2020), and Aaron Y. Zelin, “Letter from the Taliban to Abu Bakr al-Baghdadi from the Head of the Shura Council,” Lawfare, June 27, 2015, (accessed June 11, 2020).
  5. Shawn Snow, “ISIS Loses More than Half Its Fighters from US Airstrikes and Taliban Ground Operations,” Military Times, February 27, 2020, (accessed June 11, 2020).
  6. Eric Schmitt, Thomas Gibbons-Neff, Helene Cooper, and Alissa J. Rubin, “Its Territory May Be Gone, but the U.S. Fight Against ISIS Is Far from Over,” The New York Times, March 24, 2019, (accessed June 11, 2020).
  7. United Nations Security Council, Eighth Report of the Secretary-General on the Threat Posed by ISIL (Da’esh) to International Peace and Security and the Range of United Nations Efforts in Support of Member States in Countering the Threat, S/2019/103, February 1, 2019, p. 7, (accessed June 12, 2020).
  8. Snow, “ISIS Loses More than Half Its Fighters from US Airstrikes and Taliban Ground Operations.”
  9. Thomas Gibbons-Neff and Mugib Mashal, “ISIS Is Losing Afghan Territory. That Means Little for Its Victims,” The New York Times, December 2, 2019, (accessed June 12, 2020).
  10. Ahmad Sultan and Rafiq Sherzad, “Afghanistan’s President Claims Victory over Islamic State,” Reuters, November 19, 2019, (accessed June 12, 2020).
  11. Institute for Conflict Management, South Asia Terrorism Portal, “Fatalities in Terrorist Violence in Pakistan 2000–2019,” data as of June 23, 2019, (accessed June 12, 2020).
  12. Ankit Panda, “Jaish-e-Mohammed Leader’s ‘Global Terrorist’ Designation Is Overdue,” The Diplomat, March 4, 2019, (accessed June 12, 2020).
  13. Hans M. Kristensen, Robert S. Norris, and Julia Diamond, “Pakistani Nuclear Forces, 2018,” Bulletin of the Atomic Scientists, Vol. 74, Issue 5 (September 2018), pp. 348–358, (accessed June 12, 2020). See also Zeba Siddiqui, “Factbox: India and Pakistan—Nuclear Arsenals and Strategies,” Reuters, March 1, 2019, (accessed June 12, 2020).
  14. Fact Sheet, “Nuclear Weapons: Who Has What at a Glance,” Arms Control Association, last reviewed July 2019, (accessed June 12, 2020).
  15. Peter R. Lavoy, ed., Asymmetric Warfare in South Asia: The Causes and Consequences of the Kargil Conflict (Cambridge, UK: Cambridge University Press, 2009), p. 10.
  16. Table, “Theft Ranking: Countries with Weapons-Usable Nuclear Materials,” in Nuclear Threat Initiative, NTI Nuclear Security Index, Theft/Sabotage: Building a Framework for Assurance, Accountability, and Action, Fourth Edition, September 2018, p. 10, (accessed June 12, 2020).
  17. Stephen P. Cohen, “The Future of Pakistan,” The Brookings Institution, South Asia Initiative, January 2011, p. 51, (accessed June 12, 2020).
  18. Siddiqui, “Factbox: India and Pakistan—Nuclear Arsenals and Strategies.”
  19. Fact Sheet, “Nuclear Weapons: Who Has What at a Glance.”
  20. Associated Press, “Worst Fighting in Years over Disputed Kashmir,” CBS News, October 9, 2014, (accessed June 11, 2020).
  21. Ralph Ellis, Euan McKirdy, and Harmeet Shah Singh, “Indian Prime Minister Urges Pakistan to Investigate Attack on Military Base,” CNN, updated January 5, 2016, (accessed June 11, 2020).
  22. Ravi Krishnan Khajuria, “Jammu Army Camp Attack: Two Soldiers Killed as JeM Militants Storm into Sunjuwan Base,” Hindustan Times, updated February 10, 2018, (accessed June 12, 2020), and BBC News, “Pulwama Attack: Nine Killed in Kashmir Gun Battle,” February 18, 2019, (accessed June 12, 2020).
  23. Press Trust of India, “Pakistan Court Adjourns Hearing Against Hafiz Saeed in Terror Financing Cases for Indefinite Period in Wake of Coronavirus,” The Economic Times, last updated April 15, 2020, (accessed June 11, 2020).
  24. Ayaz Gul, “Pakistan Equips Military with Tactical Nuke-Capable Missile,” Voice of America, January 24, 2019, (accessed June 11, 2020).
  25. Sushant Singh, “Inside the Surgical Strike: Choppers on Standby, 70–80 Soldiers,” The Indian Express, updated October 1, 2016, (accessed June 11, 2020).
  26. Joanna Slater, “India Strikes Pakistan in Severe Escalation of Tensions Between Nuclear Rivals,” The Washington Post, February 26, 2019, (accessed June 11, 2020).
  27. BBC News, “India and Pakistan Blame Each Other over Kashmir Shelling,” October 21, 2019, (accessed June 11, 2020).