The withdrawal of U.S. military forces from Iraq, completed on September 30, 2026, ends one of the longest periods of American military involvement in the Middle East. Although U.S. forces were not continuously deployed in the same numbers throughout the entire period, American military involvement in Iraq began with the 2003 invasion, continued through years of insurgency and sectarian warfare, ended formally in 2011, and then resumed in 2014 when the Islamic State seized large areas of Iraq and Syria.

Washington and Baghdad agreed in September 2024 to a phased transition away from the U.S.-led coalition mission known as Operation Inherent Resolve, and yesterday’s withdrawal represents the fulfilment of that agreement.

The Iraq invasion in 2003 shifted the central front in the global war on terrorism away from Afghanistan and to the Middle East. During the early years of the U.S. occupation, terrorist groups poured into Iraq to attack U.S. forces and Iraqi civilians. The Iraq War cost the U.S. over thirty-seven thousand casualties, including over four thousand killed and more than one trillion dollars in military spending. Tens of thousands of Iraqis were killed, though the exact number will probably never be known. 

Iraq today remains a fragile nation still trying to recover from the U.S. invasion. A weak national government in Baghdad faces a number of threats, including Iranian-backed militias that continue to operate from Iraqi soil. Though Iran and Iraq are both majority Shi’ite nations, Iraqis are wary of their Iranian cousins, and most Iraqis do not want to be ruled by Tehran or harassed by Iranian militias. Because Iraq contains the fifth largest proven reserves of oil in the world, the struggle to control and benefit from the export of oil will likely continue to shape Iraq’s future.

A central reason for the U.S. departure is that Iraqi forces are now considered substantially more capable of handling their own security than they were when ISIS swept across the country in 2014. American and coalition troops spent years training Iraqi counterterrorism units, regular security forces and Kurdish Peshmerga, while providing intelligence, surveillance, and air support. By late 2025, many advisory responsibilities were already shifting from the multinational coalition to a more conventional bilateral U.S.-Iraq security relationship.

The U.S. departure from Iraq carries risks. The Islamic State no longer controls major territory, but intelligence officials continue to warn about sleeper cells and insurgent activity. Some Iraqi officials and residents fear that removing American intelligence, surveillance, and military assistance could create opportunities for ISIS to rebuild. Iranian influence could increase in Iraq now that the U.S. is gone, and it is likely Iran will continue to meddle in Iraqi affairs.

The U.S. departure from Iraq brings to a close a twenty-three-year chapter for the American military. But U.S. forces will likely continue to have a broad presence in the Middle East, with personnel still stationed in nearby Jordan, Bahrain, and Qatar. Though American efforts to topple the regime in Tehran have thus far failed, the U.S. government does seem to have learned one lesson from Iraq, that a ground invasion of Iran would not be worth the cost.