U.S. military forces completed their withdrawal from their last bases in Iraq on September 30, ending more than two decades of American military presence in the country. The departure concludes an agreement reached under the Biden administration in 2024 and executed during the Trump administration, with remaining missions to fight Islamic State militants now headquartered in Jordan. Approximately 1,500 U.S. and coalition personnel had been stationed in Iraq in recent months prior to the final pullout.

The U.S. invasion of Iraq in 2003 aimed to overthrow Saddam Hussein’s regime and dismantle alleged weapons of mass destruction, leading to a prolonged conflict that resulted in significant casualties. Over 4,500 U.S. service members died during the course of the conflict and related operations, alongside an estimated 210,000 Iraqi civilian deaths. After a full withdrawal in 2011, American forces returned in 2014 to assist Iraqi and allied forces in defeating the Islamic State’s territorial caliphate, a campaign that lasted until 2017.

The withdrawal has elicited contrasting reactions within Iraq and the broader region. Iranian officials and allied militias regard it as a strategic victory affirming Iraqi sovereignty and a historic defeat of U.S. occupation efforts. Abu Mojtaba al-Yasiri, a commander in the Iran-backed Islamic Resistance in Iraq, described the pullout as a turning point ending a period of foreign imposition. Iran’s parliamentary deputy chairman, Amir Hayat Moqaddam, welcomed the departure and expressed support for the Iranian-aligned “axis of resistance” in Iraq.

However, Iraqi security analysts and local leaders express concern that the timing of the withdrawal may leave a security vacuum. Jasim al-Bahdali, an expert on armed Shi’ite groups allied with Iran, warns that Tehran and its proxies stand to gain increased influence over Iraq’s political and security institutions. Sunni tribal leader Abdulrahman al-Zobaie from Fallujah echoed fears that Iraq remains unprepared to fully assume security responsibilities, pointing to risks posed by empowered militia groups.

There is also apprehension about the resurgence of Islamic State. Iraqi and Kurdish security officials report recent sleeper cell activity and intelligence indicating that ISIS may seek to exploit the diminished U.S. presence to carry out attacks. Colonel Khalid al-Bayati of Kirkuk noted that ISIS aims to demonstrate its capacity to launch lethal operations despite previous military setbacks.

In Baghdad, the government has called for disarmament of Iranian-backed militias, setting a tentative deadline of June 2027. Yet progress has been uneven, with some groups only partially complying as splinter factions remain active, receiving Iranian support and reportedly carrying out cross-border attacks, including against Saudi energy infrastructure.

The U.S. will continue counter-ISIS operations from Jordan, where officials affirm readiness to intervene in Iraq or Syria if militant threats escalate beyond regional control. Meanwhile, the shifting balance in Iraq highlights Iran’s deepening influence—as well as emerging regional dynamics such as expanding ties between Gulf Arab states and Israel, which some analysts view as a strategic counterbalance to Tehran’s ambitions.

Overall, the American withdrawal from Iraq marks the end of a significant chapter in U.S. military engagement but leaves unresolved questions about Iraq’s stability, Iran’s regional role, and the ongoing threat posed by extremist groups.