On Sept. 30, the day the United States completed its military withdrawal from Iraq, the Islamic Revolutionary Guard Corps (IRGC) issued a victory statement. "America left, neither through negotiation nor as a favor,” it declared, calling the exit the first step in avenging Qassem Soleimani and Abu Mahdi al-Muhandis. The message, however, was aimed as much at home as abroad. It came the same week U.S. President Donald Trump rejected the road map Foreign Minister Abbas Araghchi had presented at the United Nations, and the timing suggests an effort to show Iran’s negotiating camp that resistance pays. Yet, the withdrawal followed a timetable agreed between Baghdad and Washington.

In September 2024, the two governments agreed on a two-phase schedule under which the coalition mission would end in federal Iraq in September 2025 and at the northern bases a year later. On withdrawal day, Trump wrote that he had "refused to let a temporary presence become a permanent one.” Baghdad’s political landscape also changed in the months before the withdrawal, with U.S. pressure among the factors at play. Nouri al-Maliki’s candidacy was dropped earlier this year after Trump threatened to suspend security cooperation, and the political wings of six U.S.-designated groups were left out of the Cabinet. In July, Secretary of War Pete Hegseth linked trade and defense cooperation to the disarmament of the armed groups. Trump has described Prime Minister Ali al-Zaidi as "somebody I supported from the beginning.”

Baghdad, for its part, is pressing ahead with centralization. At the U.N. General Assembly, al-Zaidi said decisions of war and peace belong to the state alone. He has also said the U.S. withdrawal leaves "no justification or need for any resistance” and that he will not accept "a state within the state.” In June, a committee was formed to fully separate the Popular Mobilization Forces (PMF) from parties and armed factions. Muqtada al-Sadr handed his armed wing to the state, and Asaib Ahl al-Haq began handing over its heavy and medium weapons. The holdouts are now a small core led by Kataib Hezbollah and Harakat al-Nujaba. The trend also extends to the Kurdistan region, where there is talk that Bafel Talabani’s recent Baghdad-leaning moves could reopen the question of its current status.

For Iran, this shift is a test of an influence that long predates 2003. From the 1980s, Tehran hosted the Supreme Council for the Islamic Revolution in Iraq and its armed wing, the Badr Brigade, while cultivating ties with Shiite and Kurdish opposition groups. As long as Saddam Hussein ruled, however, these networks stayed outside the state. His fall opened the state to them, and the fragmented order that followed allowed Iran to expand and entrench its power. Ethno-sectarian quota politics, rivalry among Shiite parties, and the growth of armed groups alongside the state allowed Tehran to knock on every door separately. Asaib Ahl al-Haq’s split from the Mahdi Army, and Nujaba’s from Asaib, are well-known examples of gaining influence through division. The PMF, formed after the state’s collapse before Daesh in 2014, made this parallel power structure permanent.

For years, the American military presence was this fragmented order’s strongest justification, allowing armed groups to present their existence outside the state as resistance to occupation. The withdrawal removes that argument, and al-Zaidi’s remarks address it directly. With the American bases empty, responsibility for every action by the armed groups now falls on the Iraqi state. When drones launched from Iraq hit Saudi Arabia’s East-West pipeline in September, Baghdad traced the launch site to Maysan and dismissed the local commander. The withdrawal Tehran is celebrating thus narrows the rhetorical ground on which its influence in Iraq rests.

For this reason, Tehran is quietly slowing integration and trying to shape it to its advantage. Quds Force commander Esmail Qaani reportedly told the factions during an August visit to Baghdad not to surrender their weapons for now. In Baghdad, Iranian pressure is widely cited as one reason the disarmament deadline slipped from Sept. 30 to June 2027. The PMF law the Cabinet sent to Parliament as the withdrawal ended can be read in two ways. The government says it ties the PMF to the commander in chief, while critics warn it will entrench a parallel institution modeled on the IRGC.

The hard core, meanwhile, is now directing its pressure at the government itself. After U.S. secondary sanctions on Iranian aviation took effect on Sept. 23, the airports of Baghdad, Najaf, Irbil and Sulaymaniyah halted Iranian flights within days. Kataib Hezbollah security official Abu Mujahid al-Assaf responded with an Oct. 1 deadline, warning that if the restrictions continued, the crossings of "countries taking part in the blockade” would be closed. A government that does not serve the people, he added, would be brought down "by all means.” The target of resistance rhetoric has thus shifted from American bases to the Iraqi government’s own decisions.

Relations between Baghdad and Tehran are also under strain. On Sept. 22, al-Zaidi said that although Iraq regards itself as Iran’s regional partner, Tehran had refused to let Iraqi tankers through Hormuz. Iran’s aim, he said, is to push up oil prices and "create pressure.” Iraq has lost around $60 billion in revenue in the war, and al-Zaidi’s complaint indicates that trust, Tehran’s main capital in Iraq, is wearing thin. The disputes are not limited to Hormuz. When al-Zaidi visited Tehran in July, Iran reportedly demanded its full $11 billion gas debt and rejected Baghdad’s proposed compromise. Hard-line outlets in Tehran, for their part, accuse al-Zaidi’s government of currying favor with Washington.

Tehran’s position thus amounts to a preference for selective centralization. A Baghdad that is strong against rival communities but weak against Iran’s allies suits Tehran. A Baghdad with one army, one budget and one decision on war and peace does not. The same logic explains why circles close to Iran keep trying to redirect the arms-monopoly debate toward other armed structures. Yet, centralization applied selectively against one community becomes a new source of division and feeds the conditions that sustain Iran’s influence. Lasting stability in Iraq is possible only with a central state that holds a monopoly on arms and embraces all communities.

Iran’s position in Iraq will depend on how far Baghdad is willing to push integration. The first test comes at the end of December, when the 90-day no-attack period expires, and the handover of weapons is due to begin. The final shape of the PMF law will show whether the PMF comes to resemble the state or the state comes to resemble the PMF. Tehran may celebrate the withdrawal as a victory, but Iran’s strength in Iraq has always rested on the country’s fragmentation. As Baghdad consolidates, the withdrawal may mark the start of Tehran’s loss of its most important asset in Iraq.