Troops in Peril: The Risks of Keeping U.S. Troops in Iraq and Syria

Overview

Introduction

The gradual slowdown of the U.S. war on terror¹resulted in a new force posture in the Middle East: a limited presence of U.S. special operators and conventional troops dispersed across Iraq, Syria, and neighboring countries like Jordan. These troops operate either at the invitation of the host country, as seen in Iraq or Jordan, or at the invitation of a partner force with territorial control and acquiescence from the central government, as observed in Syria where U.S. troops are partnered with the Syrian Democratic Forces. While these deployments differ from the highly kinetic combat missions seen at the peak of the U.S. wars in Iraq and Afghanistan, they are not entirely non–combat either, representing something different: open–ended special operations and advisory missions in combat zones. If a broader conflict erupts in the region, the roughly 3,300 U.S. troops in Iraq and Syria, along with supporting troops in Jordan, could be targeted and potentially drag the United States into a larger conflict.

The presence of U.S. troops in Iraq and Syria, along with those in border regions of third countries supporting these missions, serves as an inadvertent tripwire for escalating conflicts. Local militias, often backed by Iran, target U.S. troops for their own motives, sometimes acting under Iranian direction and at other times independently. This situation adds significant potential for miscalculation and escalation. Because their mission in Iraq is to train local forces and not wage war against ISIS or Iranian–backed militias, the small number of U.S. troops in Iraq — around 2,500 — do not shift the balance of power or effectively manage either containing ISIS or deterring Iran–backed militias. In Syria, the 800 or so troops have a limited mission for which the small size of the force is appropriate but it is easily targeted by drones or missiles and rockets. 

The October 7 Hamas attacks and Israel’s subsequent military campaign in Gaza highlight the ongoing unpredictability and interconnectedness of conflicts in the Middle East. The war in Gaza has reverberated across the region’s geopolitical fault lines from southern Lebanon to the Red Sea, reaching Baghdad. It serves as the linchpin providing ideological cover for armed factions challenging the U.S. military from Iraq to the Red Sea in a region that National Security Adviser Jake Sullivan recently described as “quieter today than it has been in two decades.”²Forward deployed U.S. troops find themselves stuck in the middle. 

The correlation between the war in Gaza and attacks on U.S. troops and facilities in Iraq and Syria is evident. According to the Defense Intelligence Agency and Combined Joint Task Force – Operation Inherent Resolve, there were no attacks by Iran-aligned militias in the third quarter of 2023, which ended one week before Hamas’s attack on Israel.³But after the onset of the Gaza conflict, the Pentagon recorded at least 134 attacks on U.S. interests in Iraq and Syria in the final quarter of 2023.⁴This trend continued into 2024, including an incident where three U.S. soldiers were killed in Jordan on January 28. While attacks by Iran–aligned militias have occurred in previous years, the increase in frequency following the war in Gaza is notable. For example, in the first eight months of 2022, there were only 30 indirect fire attacks.

The risks facing U.S. troops in the region also includes the potential for retaliation due to actions by U.S. partners, notably Israel. Amid the ongoing conflict in Gaza, tensions between Israel and Iran are escalating. Israeli strikes on Hezbollah have occurred deeper within Lebanese territory than usual.⁵The Islamic Resistance in Iraq claimed responsibility for a drone strike on Eilat, Israel’s southernmost city, on April 1, resulting in no casualties.⁶On the same day, an Israeli strike in Syria and  Lebanon killed the senior commander of Iran’s Islamic Revolutionary Guard Corps (IRGC), along with six others, near the Iranian consulate in Damascus. Tehran views this as a significant escalation and is taking a page out of Washington’s playbook by holding the United States responsible for Israel’s actions.⁷Iran’s April 13 drone and missile attacks on Israel and a potential Israeli response make the situation even more dangerous. Washington’s adversaries have political and strategic reasons to target U.S. troops and interests in response to Israeli strikes on high value targets. Without a ceasefire in Gaza and reduction in regional tensions, it’s hard to imagine how Washington can avoid being drawn into these escalations. 

U.S. policymakers must address whether the security benefits gained from maintaining forward-deployed troops in Iraq and Syria outweigh the significantly greater risks involved. The answer is that they do not and planning for a withdrawal should be commenced. In the short term, Washington should continue to push for a ceasefire in Gaza. U.S. Special Envoy to Yemen Timothy Lenderking said publicly that a ceasefire in Gaza could potentially stop Houthi attacks in the Red Sea.

The new forever deployment: Leaving and returning to Iraq

Following the success of U.S.–supported Sunni militias in Iraq’s Anbar province and Baghdad in 2007, conditions appeared favorable for U.S. troops to suspend combat operations. Then-senator Barack Obama campaigned in 2008 with a promise to withdraw from Iraq. The U.S. formally suspended combat operations in August 2010, with plans for a full withdrawal outlined in the 2008 Strategic Framework Agreement and Security Agreement with Iraq. The Obama administration, however, aimed to maintain a pilot light for its U.S. military presence in Iraq, even as most U.S. troops would depart. Despite efforts to negotiate an updated Status of Forces Agreement (SOFA) in 2011, the Iraqi government’s rejection made keeping U.S. troops in Iraq untenable. In October 2011, President Obama announced the end to the U.S. war in Iraq.⁸On December 18, 2011, the last U.S. combat troops left Iraq and Operation Iraqi Freedom came to a quiet close. Since the SOFA negotiations with the Iraqi government had failed, the Office of Security Cooperation–Iraq, which was supposed to number in the thousands, became a shell of what was envisioned with approximately 200 U.S. military personnel.⁹

Unfortunately, the most violent phase of the Sunni Islamist insurgency followed, marked by the formation of ISIS and its cross–border caliphate in April 2013, leading to the rapid capture of the Iraqi cities of Ramadi, Fallujah, and Mosul. In 2014, this led to the launch of Operation Inherent Resolve (OIR) to fight ISIS. By the end of 2021, U.S. combat operations in Iraq formally ended and transitioned to a mission to advise, assist, and enable Iraqi partner forces.¹⁰

The experience of leaving Iraq and returning a little over two years later, following a successful campaign against ISIS with minimal U.S. casualties and scant negative public attention, strengthened the belief in Washington that a small number of U.S. troops should remain in places like Iraq and Syria. Their role would primarily be advisory, with only some special operators engaging in active combat. Partner forces would do most of the fighting and dying. This setup would provide the U.S. with the capability to quickly deploy and surge troops in the event of a crisis similar to the rise of ISIS in 2013. This arrangement works well for the Iraqi government and even some of the quasi–integrated Iran-aligned militias. The U.S. troop presence has contributed to keeping ISIS at bay and facilitated continued U.S. aid to Iraq. The Iraqi government can voice concerns when the U.S. violates Iraqi sovereignty by conducting strikes against Iraqi militias, but they don’t have to expel U.S. troops. In fact, even some Iran–aligned militias appear to prefer the U.S. to remain, fearing U.S. economic retaliation against Iraq. However, with each attack on U.S. troops by Iran–aligned militias and the subsequent retaliatory strikes, the U.S. military mission in Iraq encounters challenges shaped by Iraqi and U.S. domestic politics, along with the potential for U.S. casualties.

The rise of ISIS also prompted approximately 50 U.S. special operations soldiers to enter Syria in 2015 following an unsuccessful attempt to train Syrian rebels.¹¹The approximately 800 U.S. service members currently deployed to Syria have a direct combat role with their partners, the Syrian Democratic Forces, an affiliate of the Kurdish Workers Party (PKK).¹² However, from a force posture perspective, the presence in Iraq and Syria is intertwined. The U.S. mission in Syria relies on logistical support and resupply from Iraq.

The successful degradation of ISIS in Iraq and Syria is a testament to the effectiveness of the U.S. military, its partner forces, and other anti–ISIS groups, including Iran-aligned militias, in Iraq and Syria. Despite this military success in eliminating ISIS as a major threat, the presence of U.S. troops in the region has become more complex. As the International Crisis Group recently observed, “[a]s ISIS’s territorial control in Syria and Iraq shrinks, territories previously held by the group leave a vacuum for conquering parties to further their own influence and agendas.”¹³Additionally, with ISIS no longer posing an existential threat to Iraq, Iran–aligned militias in the country have shown a willingness to shift their focus to U.S. troops, and the Iraqi government, which is currently composed of the political wings of some of those same militias, and has failed to control their actions.

Weighing the pros and cons of the defeat ISIS mission

While U.S. troops play a crucial role in anti–ISIS efforts, providing intelligence, technical expertise, and advice, the threats they address are comparatively minor compared to the risk of escalation they pose. Some argue for the indefinite presence of U.S. troops, suggesting that withdrawal would cede the region to Iran.¹⁴However, this perspective doesn’t align with reality, as Iranian–aligned militias already operate freely in Iraq and Syria, integrated into the Iraqi government and are accepted by CENTCOM as a ground–level reality. The continued deployment of U.S. troops is used by these militias to enhance their well established legitimacy. U.S. troop withdrawal could equally result in increased influence and self–aggrandizement by Iran and Iran–aligned militias in Iraq. This would inevitably prompt criticism in Washington, with detractors accusing the U.S. of finalizing Iranian control over a state the U.S. fought hard to consolidate during the civil war of 2005–8. However, the reality is that Iraq holds greater strategic importance for Iran than it does for the United States. U.S. policy would be more effective and consistent if it acknowledged this disparity in vital interests and adjusted accordingly. In effect, this is what the Biden administration has been doing by maintaining a relatively small training mission, avoiding any increase in the force level despite the latest regional crisis, and at the same time shifting the focus of the bilateral relationship to improving governance and economic performance.

The deaths of three U.S. Army reservists deployed to Tower 22 on January 28, a logistical base in Jordan near the Syrian border that supports the U.S. mission in Syria, following an attack by a drone operated by an Iran–aligned militia based in Iraq, highlights the fragility of forward deployments in contested arenas.  In response, the Biden administration faced a domestic political outcry and retaliated by targeting numerous militia facilities in Iraq and Syria. Detractors contended that the U.S. retaliatory strikes failed to restore deterrence since they were telegraphed ahead of time to avoid Iranian casualties. The jury is still out on this, because the attacks did stop following the U.S. response. Recent history tells a different story. President Trump’s assassination of Iran’s Quds force commander Qassem Soleimani stopped attacks, at least temporarily, but did not succeed in quelling militia activities or their ability to resume attacks. Instead, it increased the unpredictability of the militias by diminishing Tehran’s control, which was primarily centered around Soleimani’s cult of personality and relationships. Striking back against high–ranking Iranian figures may feel good, but it won’t effectively safeguard American lives. At best, it might temporarily disrupt Iran’s network of militants, and at worst, it carries the risk of sparking a wider conflict.

Conclusion

U.S. policymakers and military planners are understandably cautious about withdrawing from Syria and Iraq due to past experiences. The reentry of U.S. troops and their ability to coordinate airpower played a key role in weakening ISIS. If troops had been deployed in Iraq in 2013, they might have detected issues in the condition of Iraq’s military and the emergence of ISIS earlier, although deploying them across Iraqi cities was unlikely. Nonetheless, their presence could have sped up the initial response. However, it’s crucial not to learn the wrong lessons. The rise of ISIS cannot solely be attributed to the U.S. withdrawal. Rather, it was largely shaped by Iraq’s complex intra–sectarian dynamics, particularly the sense of marginalization, both real and imagined, felt by the country’s Sunni minority.  

ISIS still poses risks, operating in rural parts of northern and western Iraq at night. Regional affiliates of ISIS such as Islamic State – Khorasan Province (ISKP) still have transnational ambitions as can be seen by the successful attack on a concert hall in Moscow in March. Detention centers like al–Hol in Syria also pose risks due to slow repatriation and potential radicalization. However, various regional actors, including Iran–aligned militias, have incentives to contain ISIS. It’s unlikely that Iraq or regional countries such as Iran or Turkey would ignore ISIS threats in the future even without U.S. troops. Keeping U.S. troops to monitor Iranian activities goes beyond their intended purpose and clearly isn’t effective given Iran’s relative freedom of operation between Iraq and eastern Syria. Of course, monitoring does not imply interdiction and, consistent with a restraint posture, US forces have not — as far as we know — sought to escalate tensions with Iran by using force to block its movements in Syria. U.S. troops have, however, responded to persistent attacks in self defense, without taking the offensive — again, as far as we know. However, the risk of escalation still remains.

U.S. troops in the region are vulnerable to shifting dynamics and can serve as a liability to missions elsewhere, such as aid missions to Gaza or naval responses to the Houthis, since armed groups can target them for retaliation or as a spoiling tactic. Temporary training missions should continue, but the benefits of keeping U.S. troops in Iraq and Syria are now outweighed by the risks. As Washington thinks through its options, it should consider ways to protect U.S. interests and preserve Iraqi autonomy through economic initiatives and diplomatic engagement.

Authors

Adam Weinstein

Deputy Director, Middle East Program

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Adam Weinstein is deputy director of the Middle East program at the Quincy Institute. His research focuses on security, trade, and rule of law in Afghanistan and Pakistan. He is a veteran of the Marine Corps and the war in…

Steven Simon

Senior Research Fellow

Steven Simon is a senior research fellow at the Quincy Institute. He studied theology at Harvard and public policy at Princeton before government service at the State Department and the NSC.

1. Major U.S. military operations in Afghanistan slowed after 2014 with the end of the International Security Assistance Force (ISAF). U.S. troops left Iraq in December 2011 only to return again in 2014 to fight ISIS. Major U.S. operations against ISIS waned after 2018. ↩

2. Katie Rogers, “Jake Sullivan’s ‘Quieter’ Middle East Comments Did Not Age Well,” The New York Times, October 26, 2023, https://www.nytimes.com/2023/10/26/us/politics/jake-sullivan-foreign-affairs-israel-middle-east.html ↩

3. Lead Inspector General Report to the United States Congress, “Operation Inherent Resolve and Other U.S. Government Activities Related to Iraq & Syria,” July 1, 2023 to September 30, 2023, https://media.defense.gov/2023/Nov/27/2003347442/-1/-1/1/OIR_Q4_SEP2023_FINAL_508.PDF ↩

4. Lead Inspector General Report to the United States Congress, “Operation Inherent Resolve and Other U.S. Government Activities Related to Iraq & Syria,”, October 1-September 30, 2023, https://oig.usaid.gov/sites/default/files/2024-02/OIR_FY24_Q1_FINAL_508_0.pdf ↩

5.  Laila Bassam and Adam Makary, “At least one killed after Israeli strikes on eastern Lebanon,” Reuters, March 12, 2024, https://www.reuters.com/world/middle-east/least-one-killed-several-injured-after-israeli-strikes-eastern-lebanon-sources-2024-03-11/#:~:text=BEIRUT%2C%20March%2011%20(Reuters),%2C%20Bashir%20Khader%2C%20told%20Reuters. ↩

6. Dan Williams and Tala Ramadan, “Israel reports aerial attacks on Eilat; Iraqi militia claims launch,” Reuters, April 1, 2024, https://www.reuters.com/world/middle-east/israel-says-flying-object-east-hits-eilat-no-casualties-2024-04-01/  ↩

7. Trita Parsi (@tparsi), “When groups aligned with Iran attack the US, Washington says Iran is responsible, even if it wasn’t involved or aware,” X.com, April 2, 2024, https://x.com/tparsi/status/1775175708286783944?s=20 ↩

8. Matt Compton, President Obama Has Ended the War in Iraq, The White House, October 21, 2011, https://obamawhitehouse.archives.gov/blog/2011/10/21/president-obama-has-ended-war-iraq ↩

9. Watson, Mason. The Conflict with ISIS: Operation INHERENT RESOLVE, June 2014 – January 2020. 12. ↩

10. “Combat role in Iraq complete; invitation from Iraq reaffirmed to advise, assist, enable, U.S. Central Command, December 9, 2021, https://www.centcom.mil/MEDIA/NEWS-ARTICLES/News-Article-View/Article/2867285/combat-role-in-iraq-complete-invitation-from-iraq-reaffirmed-to-advise-assist-e. ↩

11. Cameron Glenn, Timeline: US Policy on ISIS, Wilson Center, April 27, 2016, https://www.wilsoncenter.org/article/timeline-us-policy-isis ↩

12. This number has fluctuated between 800 to 900. ↩

13. Report on Al Tanf, Syria, International Crisis Group, April 8, 2024, https://www.crisisgroup.org/trigger-list/iran-usisrael-trigger-list/flashpoints/al-tanf-syria ↩

14. Thomas L. Friedman, Inside America’s Shadow War With Iran, The New York Times, March 5, 2024, https://www.nytimes.com/2024/03/05/opinion/biden-iran-middle-east.html ↩