The U.S. military presence in Iraq is beset by paradoxes. President Donald J. Trump ran for office on a platform of minimizing U.S. troops in the region and yet has been forced to increase their numbers. Iraqis are split largely along sectarian lines on the size of U.S. presence they want in the country. Iran has long wanted all Americans, NATO allies, and coalition forces countering the Islamic State in Iraq and the Levant gone, except when ISIL rose to a level that was more than Tehran and its Iraqi proxies could handle.

The post-2011 Iraqi willingness to host the United States always was hedged: When ISIL was on the march, the U.S. assistance was welcomed. Once the ISIL threat had been countered, history was rewritten to portray the defeat of ISIL as a solo achievement of the Popular Mobilization Forces. Consequently, at least among Shia politicians, the Americans were again unwelcome. Once the immediate threat from ISIL had passed, Iranian-allied Iraqi groups began a harassment campaign firing rockets at U.S. facilities. Attacks by mainly Iranian-supported proxy groups were calculated to remain below the threshold of a U.S. response until rocket strikes on December 27, 2019 killed a U.S. contractor and two Iraqi police officers, and injured several U.S. and Iraqi personnel.

In retaliation, on December 29, Trump ordered a series of airstrikes against weapon storage and command facilities of Kataib Hezbollah, the Iraqi militia most closely aligned with Iran. This kicked off a cycle of action and reprisals that led to a prolonged attack by Kataib Hezbollah supporters on the U.S. Embassy in Baghdad, followed by the United States’ killing of Major General Qassim Suleimani, commander of Iran’s Islamic Revolutionary Guard Corps Quds Force, and Abu Mahdi al-Muhandis, Kataib Hezbollah commander and Popular Mobilization Forces deputy commander.

In the wake of these military actions, and in a strongly coercive environment that forced most Sunni and Kurdish parliamentarians to boycott the vote, the Iraqi Parliament passed a measure asking Prime Minister Adel Abdul Mahdi to withdraw the agreements permitting coalition forces to be in the country. Analysts are debating the lack of quorum and strength of this mandate and legality of it, but regardless, Iraq is a much less hospitable environment for the United States and its coalition allies than it was a few weeks ago.

Iran has since conducted a much publicized but militarily insignificant retaliatory strike. Should this response turn out to not be robust enough, Iran will probably continue to instruct Shia members of Parliament to pursue legislation regarding the withdrawal of U.S. troops. At the same times, various militias can be expected to step up measures such as firing rockets or laying mines.

Going forward, there are three major U.S. security issues in Iraq and one constant condition that dictates whether U.S. or coalition forces will remain and, if so, what will be their size and mission. The first concern is retaining the ability to continue to fight ISIL; the second is retaining some ability to moderate Iran’s regional influence; and the third is ensuring the survival of an autonomous Kurdish region in Iraq. The constant condition is the requirement to prevent significant U.S. casualties or a casualty-causing attack on an Iraqi base that houses U.S. or coalition personnel or a U.S. diplomatic compound.

The United States does not have good options if it is asked to withdraw its military from Iraq. Trump has already declared victory over ISIL, and a U.S. departure from Iraq would help fulfill his promise to voters to reduce U.S. deployments in the Middle East. But, given his hostile public comments following the Iraqi Parliament’s vote, he may still want to keep some forces in country to “watch Iran” or protect “the oil.” He seemingly has had no problem walking away from an area he foresees not returning to, as was the case in northern Syria, but may not want to sacrifice bases likely to be needed again. So, while he did not seem concerned about relatively small facilities left in Syria, he has publicly demanded compensation for U.S. improvements to the Iraqi military’s Ain al-Asad air base in Anbar province, which houses a significant number of U.S. and coalition personnel and was the primary target of Iran’s retaliatory missile strike.

Moderating Iran’s regional influence tends to be defined in theological rather than concrete military terms. The Trump administration seems to share with the administration of former President Barack Obama a conviction or hope that a U.S. and NATO coalition presence – along with training, mentoring, and assistance to select Iraqi security forces – will somehow counteract the Popular Mobilization Forces controlling Iraq’s security structure, while frustrating Iran’s sustained efforts to create a ground line of communication across Iraq and into Syria and Lebanon to support its Syrian and Hezbollah allies. Iraqi military officers and politicians who fear growing Iranian proxy integration into the government, security services, and economy see a continued U.S. presence as the only way to blunt Iran’s two-pronged campaign to seize power by proxy violence and growing electoral influence.

In the United States, the bipartisan domestic political uproar that greeted Trump’s withdrawal of support from Syria’s Kurds will likely prevent Trump from leaving Iraq’s Kurds – who have relied on some U.S. military presence since 1991 – in the lurch. Similarly, the Sunni regions of western Iraq host U.S. bases, and people in those areas do not trust the Shia-dominated Baghdad government, whose misrule was a significant factor in the rise of ISIL. Iraqi Christian and Yazidi communities have often asked for U.S. and coalition forces to actively deploy to and patrol their areas to prevent domination from Shia and Shia-aligned militias.

Therefore, there may be a few options available for maintaining a U.S. force in Iraq. One would be to subordinate the U.S. military presence into a less-provocative international mission, such as the NATO training mission.

Options such as the NATO Iraq training mission could theoretically provide a legal cover for some remaining U.S. presence. The NATO mission is led by a Canadian major general and does not highlight its U.S. components. However, the NATO allies would likely insist on a significant U.S. force protection contingent to ensure the safety of the Americans and others deployed. The NATO allies’ commitment to the Iraq mission was fragile at the start: Countries that sent troops were probably only willing to do so as long as there was a U.S. presence that could provide emergency support and extraction.

The NATO mission is currently suspended due to heightened security risks: It is unlikely to return to Iraq if there is not a more significant U.S. presence than the mission warrants by itself. Many key NATO leaders are cool toward Trump and wary of Iraq – their voting populations even more so. It is difficult to see French President Emmanuel Macron, Canadian Prime Minister Justin Trudeau, and German Chancellor Angela Merkel accepting political and military risk to provide a fig leaf for a continued U.S. presence on the ground across all of Iraq.

Alternatively, it might be possible to modify the current structure of the Combined Joint Task Force – Operation Inherent Resolve (the 17-country counter ISIL coalition) to de-emphasize the U.S. role. Canada has a 250-person coalition military force in Iraq that could host U.S. and other coalition forces. However, being the Canadian fig leaf on an American statue would require Ottawa to accept significant political and military risk for a mission unpopular in Canada and a U.S. president who is even less popular. Italy, Spain, and the United Kingdom also have significant coalition deployments in Iraq but are likely to be equally cautious in taking over a titular leadership role. The fundamental military problem for internationalizing any presence is the large number of military forces required to protect U.S. forces from attacks by hostile militias and Iranian-allied forces – this is more than any other country (or NATO) can provide and involves unacceptable risk. Of course, if the United States brings the amount of forces needed to safely operate in Iraq, the new organization would be seen as a reflagging of the U.S. presence.

This leads to a second, time-honored course of action – the slow roll. The 2014 agreement that governs the U.S. coalition presence in Iraq contains an escape clause – with a one-year delay. During discussions with the Iraqi government on ending the agreement, the United States could thin out forces in areas where hostile attacks could be expected. It would reposition forces to areas where it is more welcome – mostly in the Sunni west and Kurdish north. And then the United States could delay final implementation of a withdrawal while the Iraqi government deliberates a specific end state and Iraqi Parliament reconsiders the issue, argues over the validity of the initial vote, and eventually provides a suitable level of obfuscation for the temporary presence to become as long term as it needs to be.

The slow roll could not continue indefinitely, but the current prime minister’s caretaker status and the parliamentary weakness of the Iraqi withdrawal resolution (an advisory vote taken, some argue, without a quorum with many members of parliament under individual threat from pro-Iran militias) could be the pretext for a prolonged presence. This lingering U.S. presence could conceivably last until the Parliament either meets with a quorum and declines to reaffirm the call for withdrawal, or reverses itself, or simply declines to take further action, thus implicitly nullifying the early advisory vote.

This course of action has the security advantage of ensuring the U.S. presence is in the lowest threat areas and is big enough to protect itself and still conduct training, mentoring, and equipping for Iraqi forces and support U.S. airstrikes against ISIL as needed. Under this scenario, U.S. forces would be able to conduct their essential mission of supporting and sustaining strong and professional Iraqi security forces loyal to Baghdad’s elected government, rather than simply hunker down and focus on self-protection.

The force protection risks a U.S. presence carries with it mean that it is highly unlikely that U.S. troops could be present in Iraq in small numbers or as adjuncts to any international mission. They have to have tactical mass in any location.

It is apparent that the United States cannot rely on any other country to provide security for U.S. military or diplomatic facilities. The Iraqi government – which determinedly stopped civilian anti-corruption protesters from entering the Green Zone in October – did not immediately stand in the way when Kataib Hezbollah supporters set fire to the perimeter of the U.S. Embassy compound and attempted to breach the embassy.

The U.S. presence in Iraq has weathered major shifts in mission, purpose, and strategy. The level of Iraqi support for this mission has waxed and waned and the U.S. military presence also has brought the United States into confrontation with Iran. Trump has long indicated his wariness of sustained military involvement in Iraq and Syria, but if he pulls troops out of Iraq, he will want to do it on his terms. The United States does not have attractive options, but it has workable ones to achieve its strategic and security goals in Iraq.