Does a US military withdrawal from Iraq strengthen Iran?

Does a US military withdrawal from Iraq strengthen Iran? According to recent reports, the last US troops belonging to the global coalition to fight the Islamic State (IS) have left Iraq, with many having already departed before the 30 September 2026 deadline. The US-Israel war on Iran, which began on 28 February 2026, further accelerated the evacuation of American bases in Iraq.

The US troop withdrawal has been a long time coming, with President Donald Trump expressing regret for sending troops to Iraq in 2020, following George W. Bush's War on Terror after 9/11. In August 2020, Iraq's then Prime Minister Mustafa al-Kadhimi told the US that sending troops to Iraq was a "major mistake". Iraq agreed on a withdrawal timetable by the end of September 2026, which was incorporated into Ali al-Zaidi's government programme.

The US's earlier withdrawal from Iraq in 2014 to fight the Islamic State (IS) allowed Iran to expand its influence in the country, reinforced by armed factions that effectively acted on Tehran's behalf. By 2025, the Trump administration opposed the Coordination Framework's nomination of Nouri al-Maliki as prime minister, and by the time the US troops left, Iraq's militias had been disarmed in exchange for political positions in the government.

However, securing the disarmament commitment from armed groups has proven challenging, as the Iraqi premier must secure US approval for the cabinet composition. While some argue that the US withdrawal benefits Iran, the complex political landscape in Iraq, with its Shiite majority, makes it difficult to impose significant changes.