The United States-led military coalition has formally ended its twelve-year mission in Iraq, closing a chapter that began with the rise of the Islamic State group and culminated in the dismantling of its self-declared caliphate. The announcement marks one of the most consequential security transitions in the Middle East in recent years, shifting full responsibility for Iraq's internal stability to a national army and police force that the coalition itself spent more than a decade training and equipping.

Coalition officials describe the withdrawal as the natural conclusion of a mission accomplished: the defeat of ISIS as an organized military force capable of holding territory. But the decision to close out the mission now, rather than maintain an open-ended presence, reflects broader calculations in Washington about troop deployments abroad, Baghdad's political pressure to reclaim full sovereignty, and a judgment that Iraqi forces have matured enough to manage residual threats on their own.

A Mission Born of Crisis

The coalition's presence in Iraq traces back to 2014, when ISIS fighters swept across the country's north and west, seizing Mosul and threatening Baghdad itself. The group's rapid advance exposed the fragility of an Iraqi army that had been rebuilt from scratch after the United States disbanded Saddam Hussein's military following the 2003 invasion, a decision many historians regard as one of the gravest strategic errors of the occupation. That earlier choice left tens of thousands of trained soldiers unemployed and embittered, feeding the insurgency that metastasized over the following decade and ultimately helped give rise to the conditions ISIS exploited.

Determined not to repeat that mistake, the coalition built its Iraq campaign around training, arming, and advising Iraqi security forces rather than replacing them outright. Over years of grinding urban warfare, most notably the battle to retake Mosul, Iraqi troops backed by coalition airpower and special forces advisers gradually rolled back ISIS's territorial holdings until the group's conventional military structure collapsed.

What Withdrawal Means for Iraqi Forces

With the coalition's exit, Iraq's army, federal police, and counter-terrorism units now bear sole responsibility for preventing an ISIS resurgence and containing the country's patchwork of armed factions. Iraqi commanders have long argued that their forces are ready for this handover, pointing to years of coalition-led training programs and improved intelligence-sharing capabilities. Yet the transition raises immediate questions about whether Iraq can sustain the kind of precision counter-terrorism operations, air surveillance, and logistical support the coalition previously provided.

The stakes of getting this transition right are high. Iraq's history since 2003 has shown repeatedly how quickly security gains can unravel. American troops were formally withdrawn from Baghdad's streets in 2009 after a surge in US forces appeared to have curbed the violence, only for bombings, shootings and kidnappings to resume within months. A similar pattern followed the full American withdrawal in 2011, when sectarian tensions between Iraq's Shia-led government and Sunni communities reignited, creating fertile ground for ISIS's emergence three years later.

ISIS Remnants and Iran-Aligned Militias

Although ISIS no longer controls territory, security analysts caution that the group has not disappeared. Remnants continue to operate in Iraq's rural and desert regions, conducting sporadic ambushes and assassinations aimed at destabilizing local governance and rebuilding clandestine networks. The coalition's departure removes a layer of intelligence and air support that had been instrumental in tracking these cells, placing greater weight on Iraq's own counter-terrorism apparatus to prevent a quiet resurgence.

Equally pressing is the entrenched presence of Iran-aligned armed groups operating within and alongside Iraq's official security structure. These militias, many formally integrated into Iraq's Popular Mobilization Forces after fighting ISIS, retain independent command relationships with Tehran and have periodically clashed with American interests in the region. Their continued influence complicates Baghdad's efforts to assert centralized control over its security forces and raises the possibility that Iraq could become a proxy battleground if tensions between Washington and Tehran escalate.

A Fragile Sovereignty

The coalition's exit also reflects Baghdad's long-standing push to reclaim full sovereignty over its territory, a demand that has grown louder amid domestic political pressure and periodic attacks on bases hosting foreign troops. Iraqi leaders have sought to balance this desire for independence against the practical reality that their security forces still depend heavily on foreign-supplied equipment, training pipelines, and intelligence cooperation.

Whether Iraq can maintain the gains made against ISIS without coalition support will likely depend on factors that have plagued the country since 2003: the durability of power-sharing arrangements between Shia, Sunni, and Kurdish political blocs, the state's capacity to deliver basic services and economic opportunity in formerly ISIS-held areas, and the extent to which Iran-aligned factions are willing to operate within, rather than outside, the authority of Iraq's central government.

For now, the coalition's formal exit stands as a milestone in Iraq's long and turbulent post-invasion history, a moment officials are framing as evidence of hard-won progress. But given the country's recent past, in which battlefield victories have repeatedly given way to renewed instability, the true test of this transition will unfold in the months and years ahead.