War in the Middle East: Iran could activate its militias in Iraq

Dr. Vanda Felbab-Brown, Brookings Institution

The full scope of Iran's response to U.S. and Israeli attacks, beyond the limited strikes against the U.S. Udeid base in Qatar, yet remains to be seen. Among its options is attempting to activate the Shiite militia groups in Iraq that it has long nurtured and fostered. Those most closely aligned with the Iranian government are groups within the so-called Islamic Resistance in Iraq (IRI), such as Ketaib Hezbollah, Asaib Ahl al Haq, Harakat Hezbollah al Nujaba, Kataib Sayyid al Shuhada, Harakat Ansar Allah al Awfiya, and Kataib Imam Ali.

Iran may instruct them to begin attacking U.S. embassies and military bases in Iraq –– with the U.S. scheduled to leave Iraq by the end of 2026 –– Syria, and across the Middle East or kidnap U.S. citizens as bargaining chips. Ketaib Hezbollah has held the Russian-Israeli researcher and Princeton PhD student Elizabeth Tsurkov hostage since May 2023, after kidnapping her in Baghdad.

Highly armed and powerful, these groups have long acted with a profound lack of accountability within Iraq, permeating various of the countries’ legal and legally economies. Even groups such as Ketaib Hezbollah that have remained outside of the framework formally integrating various Iraqi militias of the Popular Mobilization Forces (PMF) into Iraqi security institutions as a special service have exercised a great deal of political power. Their violent actions have terrorized Iraqi society, even as their bosses now don suits, own economic assets worth billions, and hold seats of power in the Iraqi parliament. Their military actions have supported the Assad regime and struck U.S. military bases as well as Israel after the war in Gaza started.

Most of the time, their strikes have delivered only limited tactical punch. In the most audacious attack, widely seen as crossing many redlines and perhaps even Iran’s instructions, the IRI killed three US service members and injured 25 in a coordinated drone strike on a U.S. base in northeast Jordan on January 28, 2024. In response, the United States pummeled the pro-Iran militias in Iraq and Syria and intensified pressure on Iraq’s government to neuter the militias.

Though Iraq’s democratic future and economic inclusiveness require that the militia are disempowered, weakening them has been an excruciating task for the Iraqi government –– for many reasons, including the fact that constituent members of the Iraqi government are the political leaders of some of the militias.

After the 2024 strikes by the U.S., the militias went quiet before restarting attacks on Israel in September. Despite small casualties, Israel began threatening military action in Iraq. Wary of an expansion of the war into Iraq, the Biden administration held Israel back. But by January 2025 and through the spring, the Iraqi government engaged in negotiations with various militias, including those within the IRI, about their disarmament. No actual disarmament took place by the time Israel attacked Iran, and Ketaib Hezbollah and Harakat Hezbollah al Nujaba had rejected any disarmament, as did some militias in the PMF. But instead of being rapidly shut down by the militias, this time, the conversations got surprisingly far, and the Iraqi government showed more of wherewithal to neuter the militias.

The Iraqi government now faces a difficult choice and an opportunity. The difficulty lies in maintaining its balancing act between its religious brother, an important economic partner, an energy source, a highly influential neighbor, Iran, and the distant, withdrawing, but still powerful and intrusive United States that has structured Iraqi politics for 20 years. Iran may want Iraqi militia support against the U.S. targets, but Washington is bearing down on the Iraqi government to prevent such attacks and hold the militias on a leash.

But even vis-à-vis Iraq, Iran is currently weaker than it has been since the Iraq-Iran war in the 1980s: its external deterrence credibility has collapsed, its military and nuclear assets have been severely degraded, its economy is in shambles, and its feared asymmetric tools, such as the Lebanese Hezbollah militia group, have been gravely weakened.

Even if Baghdad calculates that the Iranian regime will survive and eventually reconstitute its military capacities and rush to acquire a nuclear bomb, and that the Lebanese Hezbollah, will be rebuilt in time, Baghdad may still decide now to move strongly against the IRI groups. Dismantling and disarming the IRI would not hurt the political and economic power of Iraqi politicians whose militias are under the PMF/Iraqi institutional framework –– in fact, it would augment it. It would loosen Iran’s grip on Iraqi politics and shore relations with the United States, even while the Iraqi government continues to formally condemn the U.S. strikes and otherwise postures against Washington.

Such a move would not free fully the Iraqi society and state from the pernicious effects of the militias, with the PMF branch still sapping Iraqi national resources, skirting the rule of law, and being a tool of suppressing democratic mobilization. But it would be an important step forward amidst a limited window of opportunity. 

Dr. Vanda Felbab-Brown is a senior fellow in the Strobe Talbott Center for Security, Strategy, and Technology in the Foreign Policy program at Brookings. She is the director of the Initiative on Nonstate Armed Actors. Felbab-Brown received her doctorate in political science from MIT and her bachelor’s in government from Harvard University.