Shiite fighters from the Popular Mobilization Units launches missiles on the village of Salmani, south of Mosul, on Oct. 30, 2016, during the battle against Islamic State militants to liberate Mosul. (Ahmad Al-Rubaye/AFP/Getty Images)

Earlier this month, Iraq’s paramilitary group raided the home of and arrested one of its own — a prominent and longtime paramilitary leader, Aws al-Khafaji. The Popular Mobilization Units (PMU) — an umbrella organization of about 50 predominantly Shiite paramilitary groups — has initiated a crackdown on groups.

The purging reveals an emerging reality in Iraq: The paramilitary groups that fought together against the Islamic State are competing against each other for power, legitimacy and resources. In this process, the PMU is further institutionalizing by centralizing power and the disparate groups that fall within its umbrella. This competition has profound implications for stability in post-Islamic State Iraq — and for how we should understand its emerging state.

Tensions within the PMU

The PMU was created in response to the rise of the Islamic State in 2014. While Iraq’s armed forces remained in disarray, the PMU brought together paramilitary organizations that quickly recruited thousands of volunteers to fight the Islamic State. Groups within the organization hold varying ideologies and sources of emulation, but the senior leadership maintains strong links to Iran.

Recently, the senior PMU leadership has embarked on raids and purges from within its own ranks to consolidate and centralize power and institutionalize the organization. This process is the PMU’s attempt to clean its image by taking more control over groups that commit violations. In a recent interview, PMU leader Abu Mehdi al-Muhandis said that certain paramilitary groups were committing violations and should be dealt with. The PMU accused Khafaji’s organization of being one of these groups.

During the fight against the Islamic State, Khafaji remained loyal to the senior PMU leaders and their Iranian allies and often spoke on behalf of the PMU. As that battle wound down, he began criticizing Iranian interference in Iraq. He also stood against the killing of his cousin, Iraqi novelist Alaa Mushthoub, who was gunned down in Karbala. He and many Iraqis believe that the gunman was linked to the PMU. To them, the novelist was targeted for his secularism and sustained critique of Iranian Supreme leader Ayatollah Ali Khamenei.

Internal Shiite power struggles

The PMU’s internal divisions are part of a wider intra-Shiite struggle for power that dominates post-Islamic State Iraqi politics. Following the summer’s elections, this fragmentation produced two competing Shiite blocs in parliament for the first time since 2003.

On one side of the internal Shiite Islamist struggle, a conservative group is led by the senior PMU leadership (referred to as the pro-Khamanei group), with allies such as the former prime minister and a vice president of Iraq, Nouri al-Maliki. This camp is close to Iran. On the other side, a reformist Shiite Islamist group with leaders such as Muqtada al-Sadr and Ammar al-Hakim seeks to limit Iranian influence and the role of the PMU in politics.

Further exacerbating the divide, a rivalry has emerged from within the conservative camp itself. Following the summer’s elections, factions within this group competed for a limited number of cabinet posts in the new government. The Fateh alliance, the electoral wing of the PMU, was unable to match each PMU leader’s expectations with the ministerial posts available to them.

These internal divisions became evident following the decision by Fateh head Hadi al-Ameri to forge an electoral alliance with his electoral rival, Sadr, one month after the vote. The decision symbolized the coming together of the two camps to form a government. However, other Fateh leaders who remained adversarial to Sadr joined forces with Maliki to negate the deal and form their own bloc.

Ultimately, Ameri was left with no choice but to break his alliance with Sadr and return to the conservative camp. The internal political struggle in the conservative camp has seen Ameri’s leadership and negotiation skills challenged. One PMU leader told the author that if Ameri could not get the PMU candidate, Faleh al-Fayadh, to become interior minister, then he was no longer fit to run the list.

PMU after the Islamic State

In the areas liberated from the Islamic State, PMU groups are also beginning to turn against each other. The rivalry is primarily driven by economics: taking territory and control over checkpoints and businesses. However, the scarcity of the spoils of the war — and the absence of an external enemy — has made these groups competitors, creating an unstable environment in the post-Islamic State areas.

The PMU’s political and economic expansion has fueled criticism from its own Shiite population. Many residents from Basra, where an overwhelming majority of PMU fighters come from, say that the PMU’s role in fighting the Islamic State under the religious fatwa made the organization sacred, but its move to seize political and economic power has besmirched their legitimacy. During the protests in September, many residents attacked the offices of PMU groups, seeing them as complicit in Basra’s economic decline.

It is unlikely that this environment will lead to an intra-Shiite civil war. None of the PMU leaders or their Iranian allies want an open conflict that would feature Shiite groups fighting Shiite groups. Instead, intra-PMU rivalries will be fought out through covert assassinations or imprisonment of potential dissidents as the organization centralizes power over the many disparate groups that make up the PMU.

The PMU may also at times reunite against a common enemy. The escalation of U.S.-Iranian tensions may bring PMU forces back together against the external threat.

Beyond violence, the internal PMU dispute is significant because it will change the shape of the organization, as it consolidates power and moves away from an umbrella organization of disparate groups. The process will also change the nature of Shiite politics in Iraq and have implications stabilizing Iraq past the cycles of collapse that mark its state-building experience since 2003. If armed groups are not held accountable and under the rule of law, the victory over the Islamic State will become another short-lived mission accomplished.

Renad Mansour is a research fellow with the Middle East and North Africa program at Chatham House and a fellow at the American University of Iraq, Sulaimani.