An intra-Shi’a civil war is beginning in Iraq. Iraqi Prime Minister Haider al Abadi and Iranian proxy leader Hadi al Ameri are locked in a power struggle to dominate the formation of the next Iraqi government. The U.S. is backing Abadi and temporarily disrupted Iran’s play in late August. ISW warned on August 28th that Iran could escalate militarily in response. Abadi and Ameri separately declared coalitions of Council of Representatives (CoR) members sufficient to gain the status of the “largest bloc” on September 2nd. The largest CoR block has the constitutional right to choose the next Iraqi Prime Minister. The resulting stalemate has protracted government formation negotiations past legal deadlines. Each side is escalating with force in order to break this political stalemate.
Iran’s proxies conducted a warning shot against the U.S. embassy in Baghdad in an attempt to compel Abadi to back down. Abadi visited the headquarters of the Popular Mobilization Forces (PMF) on September 3rd and declared his authority over all of Iraq’s armed forces.  His goal was likely to disrupt Ameri’s ability to use Iranian proxies within the PMF as coercive leverage against either Abadi or members of Abadi’s coalition. In response, ten Iranian proxy militias within the PMF declared they will respond to Abadi’s “irresponsible takeover” of Iraqi institutions and called on the Dawa party to limit Abadi’s behavior on September 4th.  The groups stated they will use “all possible means” to force coalition troops out of Iraq. Multiple mortars landed near the U.S. Embassy compound in Baghdad at night on September 6th. ISW assesses that an Iranian proxy, likely Asa’ib Ahl Al Haq (AAH), conducted the attack.
Shi’a actors aligned with Abadi and with Ameri are also escalating within a pre-existing protest movement in Basra. Abadi has lost control in Basra, where Shi’a protesters have defied a curfew and unidentified Iraqi Security Force (ISF) units have used live fire ammunition against protesters on multiple occasions since August 31st. An appeal by Grand Ayatollah Ali al Sistani on September 4th did not prevent future use of live ammunition. Attacks in Basra targeted multiple government buildings in addition to Iranian proxy militia headquarters and the headquarters of militias and political parties aligned with Abadi on September 6th. It is possible but unlikely that protesters alone conducted these attacks. Militias aligned with nationalist Shi’a Cleric Muqtada al Sadr, a member of Abadi’s coalition, were likely involved in the attacks against Iranian proxy militia headquarters. Iranian proxies were likely similarly responsible for attacks against the Dawa party and possibly government buildings. At minimum, the deteriorating conditions in Basra raise the likelihood of intra-Shi’a violence at a time when Shi’a powerbrokers have resorted to armed action to affect a protracted government formation struggle in Baghdad.
Mutual kinetic escalation between actors aligned with Abadi and those with Ameri will escalate into a full-blown civil war unless one side capitulates. ISW is monitoring the situation closely and will provide updates as appropriate.
 "Abadi leads the Popular Crowd," All Iraq News. September 3, 2018. Available: http://www.alliraqnews(.)com/modules/news/article.php?storyid=77269
 "10 Iran-backed Shia militia groups threaten Abadi, Foreign troops in Iraq," September 5, 2018. Available: http://www.kurdistan24(.)net/en/news/382a3b08-dc0c-4b3a-8703-90d9f37b8b26