The History and Resilience of Iranian-Backed Shia Militias in Iraq: Formation, Comparison, and Pillars of Resilience
Summer 2026
EXECUTIVE SUMMARY: Since 1979, Iran has built an extensive proxy network to project power despite sanctions and isolation. Among its proxies—Hezbollah, Hamas, the Houthis—Iraq’s Iranian-backed militias, consolidated under the Popular Mobilization Forces (PMF), have proven uniquely resilient. This stems from their unmatched integration into Iraq’s state apparatus, dating to the first post-Saddam government and formalized by the PMF’s 2016 absorption into the security structure. Since October 7th, the rebranded “Islamic Resistance of Iraq” has escalated attacks on American forces, Israel, and Gulf states—including strikes on Gulf infrastructure and ones resulting in American casualties—while facing minimal retaliation and no threat to its domestic standing. This contrasts sharply with Hezbollah’s degradation, the Houthis’ weakening under U.S.-British strikes, and Hamas’s diminished capacity in Gaza. Key pillars drive this resilience: political integration, Iraq’s Shia demographic majority, economic diversification, and direct geographic access to Iran. As American withdrawal nears, it remains to be seen if Prime Minister al-Zaidi’s government confronts entrenched militia power before Iraq’s proxies become permanently unassailable.
Iran’s Grand Proxy Strategy
Following the Islamic Revolution and the foundation of the Islamic Republic, Iran developed an extensive proxy network designed to expand its regional influence and combat adversaries through non-state actors. With the removal of Mohammad Reza Pahlavi in 1979, Iran faced Western economic sanctions, regional isolation, and diminished military capabilities. Many scholars argue that Iran’s comparative inferiority pushed the Islamic Republic toward a proxy strategy, though others emphasize ideological export of the revolution as an equally central motive. In the strategy’s early days, Iran’s modus operandi became evident. Iran sought to exploit the instability created by regional conflict and foreign intervention by cultivating support among the Shia population and those sympathetic to Iran’s anti-West struggle.
Iran’s earliest strategic implementation was its 1982 intervention in the Lebanese Civil War, in which it connected Shia militias, deployed Iranian Revolutionary Guard Corps (IRGC) advisers, and established training camps in the Bekaa Valley to forge a united Shia front under the “Party of God”– Hezbollah. Years later, Iran exploited the violence of the Palestinian First Intifada to begin its extensive support for Hamas and Palestinian Islamic Jihad (PIJ). Simultaneously, Iran was institutionalizing its proxy strategy with the founding of the IRGC’s Quds Force in 1990, designed to support Iran’s non-state allies and regional expansionism.
Nearly two decades later, Iran utilized the same framework under the Quds Force to exploit the Arab Spring. When the Arab uprising spread to Yemen in 2011, Iran began to provide broad support for the Houthi movement, a Zaydi Shia revivalist group with roots in northern Yemen’s tribal structure. Iran’s support for the Houthis intensified a civil war that led to the removal of Western-backed President Ali Abdullah Saleh and a deadly Saudi-led intervention. Simultaneously, the Quds Force led an intervention, composed of Hezbollah and various militia actors, to preserve Syrian President Bashar al-Assad’s reign. These noted interventions and the establishment of proxy allies mirror Iran’s actions in Iraq that have occurred from the Iran-Iraq War to the present.
The Formation of Iraqi Proxies: Political Integration and The Popular Mobilization Forces
In 1979, the same year as the Islamic Revolution, Saddam Hussein became the President of Iraq. Saddam Hussein was a Sunni Arab, a group that constituted just one-fifth of Iraq’s population, as Iraq was a majority Shia country. Fearing Iranian expansionism and believing the Islamic Republic was weak, Saddam initiated a full-scale invasion of Iran in an attempt to seize the nation’s oil. This triggered a nearly decade-long Iran-Iraq War that concluded in a stalemate. During the war, Iran began to formulate ties with Iraq’s Shia’s actors. Iran provided sanctuary to the Islamic Da’wah Party, an exiled Shia opposition.
Iran founded the Badr Organization, a military unit of Iraqi exiles trained by the IRGC to fight the Saddam Regime. While Iran forged ties with the Iraqi Shia, its full-fledged infiltration of Iraqi affairs succeeded the American invasion. After the termination of major American combat operations in 2003, the Bush Administration dissolved the existing infrastructure of the Iraqi government. In a process known as de-Baathification, the Iraqi military was disbanded, government employees were terminated, federal agencies were abolished, and the Ba’ath Party was outlawed.
De-Baathification reversed the sectarian balance, as the minority Sunnis were removed from political power, and there was now an opening for Shia domination that was non-existent during Saddam’s rule. Iran capitalized on this opening and mobilized to support Shia factions in the emerging sectarian civil war. Iran supported two Shia camps. The first camp of Shia factions was supportive of the early stages of the American invasion to end Sunni political domination and concentrated fighting against Sunni remnants of the disbanded Iraqi militia, in a sectarian war.
The second camp was more ideologically aligned with Iran and targeted American forces to end the occupation. By 2004, Iran was providing capable support to militias that represent this camp, including Kataib Hezbollah and Asa’ib Ahl al-Haq. With Iranian backing, these militias conducted the infamous roadside bombings with explosively formed penetrators (EFPs) and Katyusha rocket attacks on coalition bases. In 2005, Iranian-backed militias entered federal politics under a coalition that included several parties linked to Iran-backed militias, the United Iraqi Alliance (UIA).
The UIA ran in the 2005 transitional and full-term national elections with the endorsement of Iran-aligned Grand Ayatollah Ali al-Sistani. In the December 2005 election, which elected the first full-term government, the UIA won the majority of ballots and became the dominant faction of the ruling coalition. Nouri al-Maliki, a spokesman of the UIA and leader of the Islamic Da’wah Party, became the government’s Prime Minister.
From Iraq’s first post-Saddam election, under American oversight, the Iranian-backed Shia alliance dominated the government and controlled critical positions, including the Minister of State for National Security and Minister of Interior. Over the years, the UIA and additional Shia militias increased their state integration as the sectarian conflict evolved into a counter-insurgency campaign against the Sunni Islamic State.
In 2014, IRGC-supported militias achieved ultimate legitimization with the creation of the Popular Mobilization Forces (PMF), which is a unifying framework of most Iranian-aligned militias. In 2016, the PMF was formally integrated into the state security apparatus, providing militias with state salaries, budgets, and resources while obligating them to adhere to the orders of the Prime Minister. While the PMF appears subordinate to the state, many analysts argue that, after the defeat of the Islamic State, the PMF has acted largely on behalf of Iranian directives rather than the Iraqi chain of command, though the degree of unity across PMF factions remains debated.
Post-October 7th: The Islamic Resistance of Iraq
The activities of the PMF following Hamas’s attack on Israel demonstrate its position as a traditional Iranian proxy. On the propaganda level, the collection of militias rebranded itself as the Islamic Resistance of Iraq. On a political level, the groups continued to push for the withdrawal of American forces and closer alignment with Iran. On the military level, the militias followed Iranian orders and engaged in a major escalation despite the disapproval of the Iraqi government. Since 2023, Iran-backed militias have claimed responsibility for nearly 200 attacks on American military forces. Notable attacks include the attack on Jordanian Tower 22, killing three American troops, and the 2026 drone attacks targeting the American embassy in Baghdad.
In response to attacks, the United States has launched sporadic and limited strikes at militia leadership, without degrading their military capabilities. In 2024, the Islamic Resistance also claimed responsibility for nearly one hundred attacks on Israel, which included the use of advanced Iranian drones and cruise missiles. Most provocatively, Iraqi militias launched extensive drone strikes against Gulf states, including Saudi infrastructure and the Barakah Nuclear Energy Plant in the United Arab Emirates.
This resulted in the summoning of Iraq’s ambassadors by Gulf states and retaliatory strikes inside Iraq, confirmed by Saudi Arabia and Kuwait. Estimates have concluded that the majority of projectiles launched into Saudi Arabia during the 2026 war originated from inside Iraq, including attacks following the April ceasefire.
Parameters of Resilience and a Comparative Approach
The ability of Iraqi militias to launch such major and widespread attacks is a demonstration of their resilience. For the purposes of this paper, a proxy’s resilience is defined as its ability to engage in effective military operations to advance the interests of its sponsor state, without triggering extensive foreign intervention, domestic political constraints, and direct attacks on its sponsor.
Iraqi militias have succeeded in conducting extensive military operations under the orders of Iran without triggering any of the three scenarios—a pattern many analysts read as a testament to their resilience. Politically, umbrella parties of the PMF have maintained their popular support among the Shia, billions of state funds, presence in the governing coalition, and their arms despite extensive American pressure on the Iraqi government to pursue disarmament.
Most significantly, the PMF has attributed its attacks to being the reason for American withdrawal from Iraq, a massive political victory. On the international front, militia attacks have triggered few and ineffective strikes from Gulf states and the United States, with limited impact on their operational capabilities.
As for Iran, Iraqi militias conducted extensive strikes throughout 2024 and 2025 on numerous states, including Jordan and Israel, without triggering a direct military response. In comparison, actions from the Houthis in Yemen triggered an extensive American-British bombing campaign and Israeli attacks on critical infrastructure. The strikes are widely assessed to have degraded the Houthis’ military capabilities and weakened their political capacity, which likely contributed to their absence from direct intervention in the 2026 Iran War.
In the Gaza Strip, Hamas appears to retain only a fraction of its previous military power and governing capacity. An Arab-backed international transition process has sought to delegitimize Hamas’s governing authority, though the durability of this shift remains uncertain. In Lebanon, Hezbollah’s once-feared military power has been severely degraded by Israel, constituting a major strategic defeat. Further, Hezbollah has lost Lebanese public support and is politically delegitimized through an American-negotiated framework in which Israel and the Lebanese state will jointly disarm the terrorist organization and the federal government will reassert its territorial sovereignty. Lastly, following the overthrow of Syrian President Bashar al-Assad, Iranian proxies in Syria have been significantly weakened, and their future role remains highly uncertain. All in all, it is evident that Iraqi militias have developed a unique resilience to maintain military and political functions at a comparatively low cost compared to other actors in Iran’s proxy network.
Pillars of Resilience
There are diverse factors that contribute to the resilience of Iran-backed militias in Iraq. As previously noted under the banner of the UIA, Iranian proxies were foundational to the first government created under American occupation. Therefore, since 2005, the political wing of Iran-backed militias has been a member of every major governing coalition. Similarly, the 2016 PMF integration formalized Iranian-aligned militias within the Iraqi security apparatus.
This reflects a level of integration that other Iranian proxies have never achieved. Hezbollah is not integrated into the Lebanese Armed Forces, and Hamas has never obtained membership in the Palestinian Authority leadership. Similarly, the Houthis do not have international recognition as a legitimate government. This enables the resilience of Iraqi militias as they receive state protection and legitimization, while still operating outside of the rule of law and military command.
In practice, this complicates foreign military responses against the PMF as strikes on the PMF are de facto attacks on Iraq’s security apparatus and governing parties, and constitute a violation of sovereignty. Relatedly, Iranian proxies in Iraq are reflective of the state’s majority Shia population, enabling proxies to maintain major popular support and minimize domestic opposition. Iran’s other proxies do not have this luxury, as Lebanon’s Shia comprise only thirty percent of the population and the Zaydi Shia population of Yemen is just thirty-five percent. This showcases the favorable sectarian environment of Iraqi militias in comparison to the Houthis and Hezbollah, empowering their comparative resilience.
Economically, the PMF operates many lucrative businesses and has infiltrated industries to ensure sustained funds. The PMF founded the Muhandis General Company to ensure state funding, functioning as an economic arm modeled on the IRGC’s Khatam al-Anbia. Further, the PMF has made diverse investments in lucrative projects, including universities, luxury apartments, and commercial outlets like the Al-Rafidain Mall in Baghdad. In tandem, the PMF holds control over critical industries, including petrochemicals, petroleum, and ports, allowing it to impose informal taxes.
These arrangements ensure Iraqi proxies are resilient to potential government pressures, as they maintain their own revenue sources. Lastly, the PMF has a logistical and geographic advantage. Iran and Iraq share a nearly one-thousand-mile border. This ensures direct assistance and weapon delivery to proxies in Iraq without having to traverse vulnerable areas or be exposed to enemy disruption. In contrast, Iranian support for Hezbollah utilizes a passage through Syrian territory, vulnerable to Israeli attacks and anti-smuggling efforts by the transitional government. Similarly, significant Iranian reinforcements for the Houthis in Yemen are exposed to American naval interdiction in the Gulf. Iranian support for Iraqi militias does not face the same risk of interception, fostering additional resilience.
The Future of Iran’s Iraqi Proxies
It is difficult to predict the future of Iran’s proxies in Iraq amidst an uncertain regional war and domestic conditions. Iran will likely double down on its support for Iraqi militias and strengthen its near-term interference in Iraqi affairs to preserve its most resilient regional actor. The success of Iranian efforts to maintain the strength of Iraqi militias is unpredictable, as the new Iraqi Prime Minister Ali al-Zaidi has demonstrated a willingness to confront Iran through his recent arrest of Iran-aligned politicians and endorsement from President Donald Trump.
However, with PMF parties still a part of the governing coalition and continued refusal to relinquish arms, Prime Minister Ali al-Zaidi will face stiff limitations. Acknowledging the limitations of Prime Minister Ali al-Zaidi, the United States and its Middle East allies must push for the disarmament of this group after the completion of the American withdrawal later this year. With the Americans gone, Iraqi militias no longer have the political legitimacy to maintain arms.
If necessary, American allies should be willing to tie direct investment, aid packages, intelligence sharing, and economic integration to the disarmament of Iranian proxies. The future of cooperation with Iraq could be critical to integrating regional energy sources and combating the expansion of Turkish influence, but this remains contingent on countermeasures to Iran-backed militias. While the effectiveness of actions to weaken Iranian proxies remains unclear, these actors will certainly continue to have a significant role in Iraqi politics, and adaptations will be needed to break their resilience.
Brady Warrington is an undergraduate at George Washington University and a Summer 2026 intern at the Begin-Sadat Center for Strategic Studies.