U.S. forces exit Iraq this week under a bilateral timetable that is closing the last American military bases in the country more than two decades after the 2003 invasion. The withdrawal, negotiated by Washington and Baghdad in 2024 and completed under President Donald Trump, ends the U.S.-led coalition’s standing military mission inside Iraq while leaving unresolved questions about Islamic State remnants, Iran-backed armed groups and the future of bilateral security cooperation.
The last bases are expected to close by Sept. 30. The departure completes a process that shifted responsibility for the anti-Islamic State mission to Iraqi forces while allowing separate U.S. support for operations involving neighboring Syria to continue under arrangements negotiated with Baghdad.
U.S. Forces Exit Iraq Under a 2024 Agreement
The withdrawal did not begin as a sudden decision by the current administration. The United States and Iraq announced a phased transition in September 2024 that was designed to end the military mission of the U.S.-led coalition in Iraq while moving the relationship toward a more conventional bilateral security partnership.
The original timeline called for the coalition mission in Iraq to wind down in stages, with continued support for counter-Islamic State operations in Syria through September 2026. The Trump administration has carried out the final phase even as the regional security environment has become more volatile because of the U.S.-Iran conflict.
That timing makes the withdrawal strategically complicated. Ending a long military deployment fulfills a commitment made to the Iraqi government and reflects Baghdad’s demand for greater sovereignty, but it also removes a U.S. military presence that had served as a counterweight to Iran-backed groups operating inside Iraq.
Iran-Backed Groups See a Strategic Opening
Powerful Iraqi factions aligned with Tehran have portrayed the American departure as a victory. Some of those groups have spent years pressing for the removal of U.S. troops and have attacked American bases during periods of heightened tension between Washington and Iran.
Iraq’s political system includes parties and armed movements with close ties to Tehran, giving Iran significant influence even as Baghdad tries to maintain economic and security relations with the United States. With U.S. troops leaving their remaining bases, analysts cited by Reuters said pro-Iranian factions could seek greater influence over security and political decisions.
The withdrawal does not automatically place Iraq under Iranian control, and the country has its own competing political, religious and regional power centers. It does, however, remove one element that had limited Tehran’s freedom of action and provided Iraqi officials with an alternative security partner.
Islamic State Remains a Security Concern
The other major question is whether Iraqi forces can contain Islamic State cells without a permanent U.S. coalition footprint. The group no longer controls the large cities and territory it seized in 2014, but militants continue to operate in rural and disputed areas and have demonstrated the ability to organize attacks.
Iraqi security officials told Reuters that a suspected Islamic State cell had been preparing suicide attacks around the time of the U.S. withdrawal. That allegation does not mean a large-scale resurgence is inevitable, but it illustrates why Iraqi commanders continue to treat the group as an active security threat rather than a defeated historical movement.
American intelligence, surveillance and strike capabilities were important during the campaign that dismantled Islamic State’s territorial caliphate. Iraq has since expanded its own counterterrorism forces and intelligence capabilities, but the transition will test whether those institutions can operate effectively without the same permanent U.S. support structure on Iraqi bases.
The Human Cost Spanned More Than Two Decades
Roughly 4,500 U.S. service members died in Iraq during the years following the 2003 invasion, according to figures cited in the latest reporting on the withdrawal. Tens of thousands more were wounded, and the war also imposed enormous costs on Iraqi civilians and security forces while reshaping the country’s political order.
The U.S. mission changed repeatedly over that period. American forces toppled Saddam Hussein’s government in 2003, fought a major insurgency, withdrew in 2011 and returned in 2014 after Islamic State seized Mosul and large areas of Iraq and Syria.
Even the final months of the deployment remained dangerous. American News Brief reported in July that a U.S. service member died in northern Iraq during the controlled detonation of unexploded material from an Iranian attack drone, a reminder that personnel assigned to the anti-Islamic State mission were also exposed to the wider regional confrontation with Iran.
What Comes After the U.S. Military Withdrawal
The end of the coalition’s military mission does not mean the end of U.S.-Iraq relations. Washington and Baghdad still have diplomatic, economic and security ties, and future cooperation can include training, intelligence sharing, weapons sales and other forms of support that do not require maintaining the same permanent troop presence.
Iraq will also continue balancing relationships with neighboring Iran, Gulf Arab states, Turkey and the United States. That balancing act has become more difficult as regional conflicts place pressure on Baghdad to choose sides or enforce sanctions and security policies that affect powerful domestic constituencies.
The withdrawal could give the Iraqi government greater freedom to present security policy as a sovereign national responsibility. At the same time, it removes a familiar external partner at a moment when armed factions, Islamic State cells and regional conflict continue to create pressure on the Iraqi state.
For Washington, the final departure closes a chapter that lasted through four presidential administrations after the invasion and another two after U.S. troops returned to fight Islamic State. Whether the exit proves durable will depend less on the ceremony surrounding the last base closure than on Iraq’s ability to prevent a security vacuum and manage competing foreign influences without again requiring a large American deployment.
