The United States is bringing its coalition military deployment in Iraq to a close, marking another turning point in a relationship transformed by invasion, occupation, insurgency and the campaign against the Islamic State. Reporting available on 30 September 2026 placed the final departures on that day; it did not yet establish that every departing unit had left.
The immediate question is what replaces the departing American presence. Iraqi security analysts interviewed by Reuters warned that Iran-aligned armed groups could seek greater influence over security and political decisions once the coalition leaves. Other Iraqis regard the departure as an opportunity to exercise greater authority over their own country. These concerns and aspirations are not necessarily contradictory: a country can seek an end to foreign deployments while remaining concerned about the security arrangements that follow.
The central issue is not simply whether American troops remain in Iraq. It is whether Iraqi institutions can sustain security and control the use of armed force without the coalition’s on-the-ground support.
A Long Military Relationship—but Not an Uninterrupted Deployment
The description “after two decades” captures the historical scale of American involvement, but it can obscure the different missions conducted during that period.
The first began with the March 2003 invasion, when U.S.-led forces overthrew Saddam Hussein. Washington had justified military action partly through allegations about weapons of mass destruction that were not substantiated as claimed. The occupation was followed by an insurgency, sectarian conflict and a prolonged effort to establish new political and security institutions. The main American withdrawal took place in December 2011, ending that phase of the war.
American forces returned in 2014, this time at the Iraqi government’s invitation, after the Islamic State seized extensive territory. The subsequent deployment was smaller and centred on supporting Iraqi forces against the militant organisation. Over time, Washington reduced its role; after the announced end of the U.S. combat mission in 2021, approximately 2,500 American troops remained for training and counter-ISIS cooperation.
This distinction matters. The forces departing in 2026 were not performing the same mission, at the same scale or under the same political circumstances as those that entered Iraq in 2003. A historical assessment must distinguish the invasion and occupation from the later, invited counterterrorism partnership.
It also means the withdrawal cannot, by itself, settle every argument about the preceding 23 years. The objectives, costs and outcomes of those different phases require separate examination.
Why Washington and Baghdad Agreed to End the Coalition Mission
The timetable originated in negotiations rather than an announcement made only in the final days of September.
A joint U.S.–Iraqi statement issued on 27 September 2024 set out a two-stage transition. The coalition’s military mission in Iraq was to conclude by the end of September 2025, moving towards bilateral security partnerships. A subsequent arrangement supporting coalition operations in Syria from an agreed platform was envisaged through September 2026, subject to conditions and consultations. The statement explicitly linked the transition to continued pressure on ISIS and future security cooperation.
That original framework was therefore broader than a simple decision to terminate relations. It envisaged changing the structure through which security assistance was provided.
By August 2026, Iraqi Prime Minister Ali al-Zaidi had reaffirmed 30 September as the final departure date, and a U.S. official told the Associated Press that Washington expected to complete the withdrawal on schedule.
For Baghdad, the departure also has a domestic purpose. The government argues that ending the foreign military presence removes a justification used by armed factions to retain weapons outside effective state control. It has designated 1 October as Sovereignty Day, linking the coalition’s departure to its stated aim of strengthening government authority.
That argument creates an important distinction: removing foreign troops is one dimension of sovereignty; establishing an enforceable chain of command over domestic armed groups is another.
What an “Opening for Iran” Actually Means
An opening for Iran does not necessarily mean Iranian troops replacing American personnel at vacated bases. The more immediate concern is the influence of Iraqi organisations that already have relationships with Tehran.
In its September reporting, Reuters quoted Baghdad-based analyst Ahmed Younis, who warned that Iran’s partners could seek a greater role in state policy and public institutions after the Western military presence ends. His concern was principally about the expansion of existing networks, rather than a new conventional Iranian intervention.
Understanding those networks requires avoiding an overly simple picture of Iraqi politics. The Popular Mobilization Forces, or PMF, encompass numerous armed organisations with differing relationships to the government and Iran. In a June 2026 analysis, Chatham House’s Renad Mansour described divisions between factions signalling willingness to integrate into state structures and groups rejecting that approach. He also documented how armed-group leaders had acquired positions in parliament, ministries and the civil service.
The potential consequence is therefore institutional as well as military. An organisation with weapons, political representation and access to government resources may influence decisions without exercising formal control over the entire state. Its leverage can arise from the ability to resist orders, shape appointments or make implementation of government policy more difficult.
However, the differences among these organisations also limit the usefulness of treating them as a single, fully coordinated bloc. Iran-aligned factions, the wider PMF and Iraq’s Shia population are not interchangeable categories. The divergent positions described by Chatham House illustrate why analysis has to examine particular organisations and relationships rather than assume uniform loyalties.
The withdrawal changes the environment in which these actors operate. It does not establish in advance how much additional influence any of them will obtain.
The Unresolved Question of Militia Disarmament
The clearest indication that the transition remains unfinished is the difference between the troop-withdrawal timetable and the timetable for bringing armed groups under state authority.
Al-Zaidi initially linked the American departure to a 30 September 2026 disarmament deadline. By late September, however, he had outlined a longer process extending to 30 June 2027. According to reporting by Al-Monitor, the revised approach envisaged a 90-day suspension of attacks, followed by weapons handovers. U.S. envoy Tom Barrack told the outlet that the intended endpoint was exclusive state control over military force.
This is a proposed process, not evidence that disarmament has already occurred.
Some factions have also expanded their conditions beyond the physical departure of American troops. AFP reported demands for an end to what the groups describe as American political and economic interference. Such demands complicate the government’s argument that the withdrawal alone removes their reason for maintaining separate arsenals.
A further difficulty concerns the meaning of “integration.” Moving personnel onto an official payroll or placing weapons in a different warehouse does not necessarily establish who can order their use. Mansour’s analysis distinguishes formal incorporation from an actual transfer of command, particularly over drones and rockets.
The practical questions are consequently specific: who appoints commanders, who authorises deployments, who controls ammunition and weapons storage, and what happens when a unit refuses a government instruction?
These are questions of implementation rather than ceremony. A departure date can be announced and observed; a functioning command structure has to be demonstrated through conduct.
Could the Islamic State Rebuild?
Warnings about an ISIS resurgence are prominent in reporting on the withdrawal, but they require careful qualification.
There is evidence of substantial Iraqi counterterrorism progress. The UN Secretary-General’s report dated 31 July 2026 described Da’esh in Iraq as being at its weakest, largely because of sustained pressure from Iraqi security forces. That assessment is an important counterweight to suggestions that Iraq is already returning to the conditions of 2014.
At the same time, reduced strength is not the same as disappearance. Reuters reported concerns from Iraqi and Kurdish security officials about surviving cells and possible attempts to exploit the transition. Kurdish commander Sirwan Barzani said his forces had observed increased sleeper-cell movement; Iraqi officials also described a suspected plot timed to the withdrawal. Those are attributed security assessments, not proof that a nationwide resurgence has begun.
The more concrete issue is the continuity of specialised support. NPR’s reporting described an Iraqi military strengthened by years of training, but still facing gaps in intelligence, surveillance and air support. Those capabilities can matter even when the number of foreign troops providing or coordinating them is relatively small.
The question is therefore not simply how many soldiers Iraq possesses. It is whether forces can consistently locate threats, share information, sustain operations and respond quickly enough to prevent small networks from rebuilding.
There is also a distinction between a local increase in attacks and a renewed territorial campaign. Both deserve attention, but they represent different levels of threat. The available evidence supports monitoring for deterioration; it does not establish that the loss of territory on the scale seen in 2014 is inevitable.
Why Kurdish Concerns Are Particularly Acute
For authorities in the Kurdistan Region, the departure raises a specific concern about protection against aerial attacks—not merely the loss of a political relationship.
The Associated Press reported anxiety among Kurdish officials about the removal of U.S. air-defence systems. The regional Peshmerga Ministry warned about the withdrawal without replacement defensive arrangements.
In an interview with the Financial Times, Kurdistan Regional Government Prime Minister Masrour Barzani said the region lacked the air-defence capabilities it needed and argued that Baghdad had prevented it from obtaining them. Those claims reflect the Kurdish leadership’s position and its dispute with federal authorities over security provision.
The distinction between ground security and air defence is important. Forces capable of conducting patrols and counterterrorism raids do not automatically possess the equipment needed to intercept missiles or drones.
This helps explain why reactions to the withdrawal differ within Iraq. The same change may be understood as a reduction in foreign military involvement in one setting and as the removal of a protective capability in another. Neither perspective can be treated as representative of every Iraqi community.
Withdrawal Does Not Mean the End of U.S.–Iraq Relations
The coalition’s departure should not be confused with a complete diplomatic or security rupture.
The Washington Post reported that departing personnel were relocating to Jordan, where counter-ISIS operations would continue.
Diplomatic engagement has also continued. A 21 September 2026 State Department readout said Marco Rubio and Al-Zaidi discussed the future of the bilateral partnership, including armed groups, attacks originating from Iraqi territory and Baghdad’s exercise of sovereignty. The meeting demonstrates that these issues remain part of an active relationship despite the troop drawdown.
Other international arrangements require similar precision. NATO’s published account says its personnel relocated from Baghdad to Naples in March 2026 because of the regional security situation, while continuing NATO Mission Iraq from there. NATO describes that mission as advisory and capacity-building, rather than a combat deployment. It would therefore be inaccurate to assume that a substantial NATO force simply remains inside Iraq to replace the departing American coalition.
These arrangements point towards a relationship with fewer forces based inside Iraq, not necessarily one without external assistance.
Their practical value, however, cannot be inferred from announcements alone. Advice delivered abroad, intelligence exchanged remotely and support available on request are different from capabilities permanently present alongside Iraqi units. Assessing the transition requires distinguishing those forms of assistance rather than counting all of them as equivalent.
Economic Pressures Could Shape the Security Outcome
Iraq’s ability to manage the transition is closely connected to its public finances.
The World Bank estimates that in 2025, oil accounted for 88% of government revenues and 91% of merchandise exports. Its current country assessment says disruption to the Strait of Hormuz has reduced export capacity and slowed production. These figures describe a state whose revenue base is highly exposed to regional conflict and interruptions to energy trade.
Electricity is another point of exposure. The Financial Times reported in May 2026 that disruption of Iranian gas supplies was contributing to Iraq’s electricity crisis. This illustrates that the relationship with Iran is not confined to armed groups: energy dependence can also constrain the choices available to Baghdad.
Iraq is pursuing alternative routes for some trade. Reporting published on 30 September described gasoline imports through Syria’s Baniyas port under a three-month arrangement, following earlier efforts to export Iraqi oil through the same route.
The security relevance is straightforward. Maintaining equipment, paying personnel and providing basic services all require resources. Where revenue falls while security demands rise, governments face harder choices about expenditure.
That does not mean economic pressure automatically produces unrest or stronger militias. It means that military readiness cannot be assessed separately from the financial and infrastructure conditions that sustain it.
The Human and Financial Legacy Remains
The withdrawal also invites reflection on costs that continue after a deployment ends.
Brown University’s Costs of War project estimated in a March 2023 study that U.S. war-related expenditure for Iraq and Syria combined had reached approximately $1.79 trillion, rising to about $2.89 trillion when projected veterans’ care through 2050 was included. These are not figures for Iraq alone, nor are they an updated accounting of spending through September 2026.
The same study estimated 550,000–580,000 direct deaths among civilians and combatants across the two war zones during the periods examined, while explaining that indirect deaths from damaged health systems, displacement and other consequences were additional. Again, those numbers should not be presented as an Iraqi-only death toll.
Such estimates do not, by themselves, determine the merits of any particular withdrawal decision. They do show why the end of a military mission is not the end of a war’s consequences. Medical care, reconstruction, displacement and the effects on families continue beyond the departure of the final convoy.
What Will Determine the Outcome?
The most useful way to assess the coming period is through observable developments rather than declarations about who has prevailed.
Security continuity is one issue: whether Iraqi forces maintain pressure on ISIS without a sustained increase in attacks or the re-establishment of durable operating areas. The UN’s July assessment provides a baseline of significant progress, not a guarantee about future conditions.
Control over armed organisations is another: whether the announced weapons process produces verifiable changes in command and conduct, rather than only new administrative arrangements. The June 2027 timetable remains a commitment whose implementation has yet to be demonstrated.
Protection across different parts of Iraq also matters. The continuation of training or diplomatic cooperation does not by itself answer Kurdish concerns about air defence, nor does a general statement of national security establish that every region has access to comparable protection.
Finally, the wider regional environment will influence what Baghdad can achieve. International cooperation remains relevant to counterterrorism: UN officials warned in August that ISIS and its affiliates continue adapting through dispersed networks and new technologies despite sustained military pressure. That warning concerns the wider organisation and should not be mistaken for evidence of an identical threat level in every country.
Conclusion: A Change in Military Presence, Not a Settled Regional Outcome
The U.S. departure changes the means through which Washington engages with Iraq. It also places greater attention on Baghdad’s ability to sustain security, manage external relationships and enforce its decisions over armed organisations.
There is a documented basis for concern that Iran-aligned groups will seek to expand their influence. There is also evidence of improved Iraqi counterterrorism capacity and continuing international engagement. Neither side of that picture should be omitted.
An opening for Iran is a potential consequence of the transition—not proof that Iraq’s future has already been decided. The outcome will become clearer through weapons control, security performance, economic resilience and the actual terms of Iraq’s relationships with both Washington and Tehran.
The final departure date marks the end of a deployment. Whether it also marks a more durable security arrangement is a question that remains open.
