December 15, 2020 | Defending Forward Monograph

Learning the Correct Lessons From Iraq

December 15, 2020 | Defending Forward Monograph

Learning the Correct Lessons From Iraq

There is a striking duality to America’s military involvement in Iraq since 2003. On the one hand, Iraq is the poster child for the so-called “endless wars” of the post-9/11 era that Americans are so eager to put in the rearview mirror. On the other hand, America’s experience in Iraq is a cautionary tale about the dangers of precipitous withdrawal.

The departure of U.S. troops from Iraq in 2011 triggered a downward spiral that ended disastrously in 2014, with the Islamic State declaring its caliphate from the Great Mosque in Mosul.1 This prompted massive waves of refugees that destabilized Europe,2 and dramatically heightened the risk of mass-casualty terror attacks against the United States and its allies.3 Less than three years after supposedly ending America’s war in Iraq, President Obama was forced to rush thousands of forces back into the breach to fight a new war born of the vacuum left behind by his hasty retreat.4

In evaluating the U.S. military posture in Iraq today, the lessons of 2011, rather than those of 2003, bear the greatest relevance.5 The question that policymakers face in 2020 is not whether to sustain a large-scale ground war in the Middle East. Instead, the question is whether to keep in place a small force to support an imperfect partner in a strategically significant part of the world where adversaries still threaten important U.S. interests.

At the height of the Iraq War, there were over 170,000 American troops deployed in the country,6 many engaged in intense combat operations against insurgent forces. Nearly 4,500 U.S. service members lost their lives in Iraq from 2003 to 2011.7 In 2010, the Pentagon’s budget in Iraq exceeded $60 billion.8

By contrast, since the U.S. return to Iraq in 2014, U.S. troop levels peaked at approximately 5,200.9 Fewer than 25 have been killed in action.10 While special operators have accompanied Iraqi troops on combat missions against ISIS, the majority of U.S. assistance has been far from the front lines, in the form of air and artillery support, training, logistics, and intelligence, surveillance, and reconnaissance.11 For fiscal year 2021, the Pentagon is seeking about $7 billion to cover operations not only in Iraq but in Syria as well.12

By orders of magnitude, the size and cost of the current U.S. deployment are significantly less burdensome than in the 2000s. The nature of the U.S. role now is significantly less risky. Today, U.S. troops are acting in support of an Iraqi ground force that has shouldered nearly all the fighting and absorbed almost all of the casualties in the war against ISIS.

The downsized U.S. presence has nonetheless advanced America’s vital interest in combatting ISIS and preventing terror attacks against the homeland or U.S. global interests. At relatively low cost, with a local partner making most of the sacrifices, the territorial caliphate of one of history’s most dangerous terrorist organizations was systematically dismantled.13

The defeat of the ISIS caliphate represents a spectacularly successful model of how to leverage a small U.S. presence to achieve major counterterrorism objectives that enhance American security. The challenge now is ensuring that remnants of ISIS, which continue to fight a low-level insurgency in scattered portions of Iraq and Syria, cannot reconstitute as a major transnational terrorist threat as they did after the 2011 U.S. withdrawal. Maintaining a U.S. presence for the foreseeable future, and continuing to provide critical support to Iraqi troops, would dramatically reduce the risk of an ISIS resurgence.14

A modest U.S. military presence in Iraq also supports Baghdad’s efforts to claw back sovereignty over its security forces. Following the 2011 U.S. withdrawal, Iran exploited the emergence of ISIS to expand its infiltration of the Iraqi state. Tehran’s Iraqi Shiite allies, acting under the direction of the Islamic Revolutionary Guard Corps (IRGC), came to dominate the Popular Mobilization Forces (PMF), a state-sanctioned coalition of militias created to defend Baghdad after large parts of the Iraqi army collapsed in the face of ISIS’ invasion.15 Though formally subordinate to the Iraqi prime minister and funded in part by the government, pro-Iran PMF groups continue to conduct military operations in open defiance of the chain of command, engage in illicit economic schemes, and exercise substantial political power in the Iraqi parliament – not unlike what Iran’s most powerful foreign proxy, Hezbollah, does in Lebanon.16

Iran’s proxy militias pose the greatest threat to U.S. troops in Iraq. Since May 2019, they have repeatedly targeted American military and diplomatic personnel with mostly low-level rocket attacks.17 On the two occasions when U.S. citizens were killed, U.S. forces retaliated against militia facilities, killing numerous fighters.18 When the militias responded to the first U.S. strike by staging a violent protest that threatened the U.S. Embassy in Baghdad,19 President Trump ordered a drone strike that killed Iran’s most powerful general, Qassem Soleimani, as well as Iraq’s most important militia commander and the de facto head of the PMF, Abu Mahdi al-Muhandis.20 Within days, pro-Iran elements of Iraq’s parliament passed a non-binding resolution calling for the eviction of U.S. forces,21 while Iran attacked two bases hosting U.S. troops with short-range ballistic missiles, killing none but causing more than 100 concussive brain injuries.22

Iraqi Prime Minister Mustafa al-Kadhimi entered office in May 2020.23 A former intelligence chief with good ties to the United States, Kadhimi has prioritized Iraqi sovereignty over the Iran-backed militias. As part of a new strategic dialogue with Washington, the government has underscored its commitment to prevent attacks on American troops.24

In an effort to bolster the new premier, Trump hosted Kadhimi at the White House in August 2020.25 Shortly thereafter, the United States announced it would reduce the number of troops from 5,200 to 3,000.26 Over the course of 2020, the United States also withdrew from eight Iraqi bases, consolidating its presence in just two or three locations – acknowledging the growing capabilities of Iraqi forces against ISIS, but also seeking to protect U.S. troops from additional militia attacks.27 The United States also deployed air defense batteries to protect its remaining positions as well as the U.S. Embassy, with several successful rocket interceptions subsequently reported.28 The head of U.S. Central Command, General Frank McKenzie, expressed confidence that the smaller footprint would not significantly impair the anti-ISIS mission.

The troop reductions seemed well-coordinated with Baghdad. While managing the operational risks of a smaller U.S. presence, the move served the political needs of both sides: specifically, Trump’s promise to the American people that he was winding down the U.S. military presence in Iraq, and Kadhimi’s desire to show that the U.S. presence was not permanent.

Totally uncoordinated, however, was the U.S. threat days later to shutter its Embassy in Iraq unless the government put an end to militia attacks.29 Coming so soon after Kadhimi’s meeting with Trump, the threat blindsided not only Iraqi officials but many of their American counterparts. The move seemed triggered by an escalation of attacks on U.S. interests that occurred in the wake of Kadhimi’s Washington visit.

An embassy closure could prove highly destabilizing. It would signal a devastating loss of U.S. confidence in Kadhimi. It could cripple Iraq’s ability to attract badly needed international investment. Perhaps most concerning, it would mark a major victory for Iran’s efforts to drive the United States out of Iraq and pave the way for Tehran’s domination of the Iraqi state. Absent a diplomatic presence in Baghdad, Washington’s ability to sustain its military operations in Iraq (and Syria) would be in serious doubt.

General McKenzie has stated that Iran seeks to eject U.S. forces from Iraq.30 Doing so would clear the way for an IRGC-controlled land bridge from Iran through Iraq, Syria, and Lebanon to the Mediterranean Sea, providing Iran and its proxies with unfettered abilities to deploy advanced weapons across this geographical expanse, including precision-guided missiles that threaten U.S. interests, Israel, Jordan, and other U.S. partners.31

It makes sense for Washington to maintain pressure on the well-intentioned but weak Iraqi government as part of an effort to protect American soldiers and diplomats. But the United States should be careful not to jeopardize a very modest military presence that successfully contains dangerous threats to U.S. interests posed by ISIS and Iran. Though far from perfect, Kadhimi is an Iraqi leader who appears genuinely committed to building the U.S.-Iraqi partnership and strengthening Iraqi sovereignty. The basis exists for a sustainable and effective forward deployment that – with the disastrous lessons of 2011 in mind – the United States should not surrender.


  1. Alissa J. Rubin, “Militant Leader in Rare Appearance in Iraq,” The New York Times, July 7, 2014. (
  2. “Migrant Crisis: Migration to Europe Explained in Seven Charts,” BBC News (UK), March 4, 2016. (
  3. “Worldwide Threats to the Homeland: ISIS and the New Wave of Terror,” Hearing before the House Committee on Homeland Security, July 14, 2016. (
  4. Helene Cooper and Michael D. Shear, “Obama to Send 1,500 More Troops to Assist Iraq,” The New York Times, November 7, 2014. (
  5. After the U.S. withdrawal in 2011, the Iraqi government drew closer to Iran and became far more sectarian in its policies, alienating wide swathes of its Sunni population and creating a wellspring of latent support for ISIS when the terror group burst on the scene in 2014. A repeat performance today that again leaves Iraq without a U.S. counter-balance to the hegemonic designs of Iran and its sectarian proxies would dramatically increase the risk of major inter-communal strife and the emergence of a fertile breeding ground for ISIS’ resurrection.
  6. Amy Belasco, “Troop Levels in the Afghan and Iraq Wars, FY2001-FY2012: Cost and Other Potential Issues,” Congressional Research Service, July 2, 2009, page 66. (
  7. U.S. Department of Defense, “Casualty Status,” December 7, 2020. (
  8. Anthony H. Cordesman, “Strategic Dialogue: Shaping the Iraq-U.S. Relationship,” Center for Strategic and International Studies, July 17, 2020, page 100. (
  9. “Department of Defense Contractor and Troop Levels in Afghanistan and Iraq: 2007-2018,” Congressional Research Service, May 10, 2019, pages 13–14. (; Alissa J. Rubin, Lara Jakes, and Eric Schmitt, “ISIS Attacks Surge in Iraq Amid Debates on U.S. Troop Levels,” The New York Times, June 10, 2020. (
  10. U.S. Department of Defense, “Casualty Status,” July 13, 2020. (
  11. Secretary of Defense Ash Carter, “A Lasting Defeat: The Campaign to Destroy ISIS,” Belfer Center for Science and International Affairs, October 2017. (; AP Archive, “U.S. Artillery Supports Iraqi Forces in Mosul,” YouTube, April 22, 2017. (
  12. Anthony H. Cordesman, “Strategic Dialogue: Shaping the Iraqi-U.S. Relationship,” Center for Strategic and International Studies, page 100. (
  13. The danger the caliphate posed by virtue of the vast territory it controlled, the hundreds of millions of dollars in revenues it generated, and the tens of thousands of jihadists it recruited were dramatically reduced with its collapse.
  14. Alissa J. Rubin, Lara Jakes and Eric Schmitt, “ISIS Attacks Surge in Iraq Amid Debates on U.S. Troop Levels,” The New York Times, June 10, 2020. ( Iraq is the critical staging area from which cross-border support in the form of artillery, logistics, and intelligence collection flows to the small U.S. contingent and their Syrian Kurdish partners fighting ISIS in northeastern Syria. A withdrawal from Iraq and an end to those support activities could cripple the U.S. counter-ISIS mission in Syria.
  15. Michael Lipin and Rikar Hussein, “Pro-Iran Shiite Militias in Iraq Expanding Despite Iraqi Leaders’ Efforts to Curtail Them,” Voice of America, September 22, 2019. (
  16. Renad Mansour, “More Than Militias: Iraq’s Popular Mobilization Forces are Here to Stay,” War On The Rocks, April 3, 2018. (; Omar L. Nidawi, “The growing economic and political role of Iraq’s PMF,” Middle East Institute, May 21, 2019. (
  17. Behnam Ben Taleblu, “Collecting and analyzing Shiite militia attacks against the U.S. presence in Iraq,” Foundation for Defense of Democracies, May 5, 2020. (; “IntelBrief: Renewed Iran-Backed Attacks in Iraq Ratchet Up The Pressure,” The Soufan Center, June 22, 2020. ( Starting in summer 2020, Iran-backed groups also began using roadside bombs to attack Iraqi-manned convoys transporting supplies and equipment to U.S. forces. See: John Gambrell, “U.S. Says Blast Hits Iraq Convoy, Border Attack Claim False,” Associated Press, August 12, 2020. (
  18. Julian E. Barnes, “U.S. Launches Airstrikes on Iranian-Backed Forces in Iraq and Syria,” The New York Times, December 29, 2019. (; Eric Schmitt and Thomas Gibbons-Neff, “U.S. Carries Out Retaliatory Strikes on Iranian-Backed Militias in Iraq,” The New York Times, March 12, 2020. (
  19. Falih Hassan, Ben Hubbard, and Alissa J. Rubin, “Protesters Attack U.S. Embassy in Iraq, Chanting ‘Death to America,’” The New York Times, December 31, 2019. (
  20. Michael Crowley, Falih Hassan, and Eric Schmitt, “U.S. Strike in Iraq Kills Qassim Suleimani, Commander of Iranian Forces,” The New York Times, January 2, 2020. (
  21. “Iraq parliament passes resolution to expel US-led coalition troops from country,” France24 (France), January 5, 2020. (
  22. Idrees Ali and Phil Stewart, “More than 100 US troops diagnosed with brain injuries from Iran attack,” Reuters, February 10, 2020. (
  23. Louisa Loveluck, “Iraq names new prime minister, paving the way to tackle nation’s deepening crisis,” The Washington Post, May 7, 2020. (
  24. U.S. Department of State, Office of the Spokesperson, Media Note, “Joint Statement on the U.S.-Iraq Strategic Dialogue,” June 11, 2020. (
  25. Katie Rogers and Eric Schmitt, “Trump Meets With Iraqi Leader Amid Negotiations Over U.S. Troop Levels,” The New York Times, August 20, 2020. (
  26. “U.S. formally announces troop reductions in Iraq,” Reuters, September 9, 2020. (
  27. Maher Nazeh and Thaier Al-Sudani, “U.S.-led troops withdraw from Iraq’s Taji base,” Reuters, August 23, 2020. (
  28. “U.S. air defenses intercept rocket fired toward Baghdad’s Green Zone,” Al-Monitor, July 6, 2020. (,Iraq’s%20deputy%20speaker%20of%20parliament); Maher Nazeh and Thaier Al-Sudani, “U.S.-led troops withdraw from Iraq’s Taji base,” Reuters, August 23, 2020. (
  29. Edward Wong, Lara Jakes, and Eric Schmitt, “Pompeo Threatens to Close U.S. Embassy in Iraq Unless Militias Halt Attacks,” The New York Times, September 29, 2020. (
  30. Carla Babb, “CENTCOM Chief Says US Can Do Job in Iraq With Fewer Forces,” Voice of America, July 15, 2020. (
  31. David Adesnik and Behnam Ben Taleblu, “Burning Bridge: The Iranian Land Bridge to the Mediterranean,” Foundation for Defense of Democracies, June 18, 2019. (


Jihadism Military and Political Power U.S. Defense Policy and Strategy