Can anyone stop Iran from taking over Iraq?

Mosul is back in the Iraqi government’s hands and the war against the Islamic State seems to finally be approaching its end. This is the good news. But one of the byproducts of the campaign is that Iran’s reach now extends even deeper throughout Iraq and seems unlikely to go away any time soon.

A crucial fighting force in the battle for Mosul and other areas liberated from the Islamic State was provided by paramilitary groups that receive supplies and support from Iran, and cross the Iran-Iraq border at will. These were sanctioned by the Iraqi government in November 2016 and made part of the Popular Mobilization Forces, a coalition of paramilitary groups, some of which have multiple loyalties.

Abu Mahdi al-Muhandis, a paramilitary commander who is considered one of Iran’s closest Iraqi allies, declared on July 4 that the Popular Mobilization Forces will not go away, even if the government orders them to dissolve. Mr. Muhandis’s statement essentially amounted to Iran saying that it plans to protect its interests in Iraq for years to come. These units, and the political forces that are associated to them, intend to prevent Iraq from establishing its own independent security policy, which could limit Iran’s ability to support its allies in Syria and elsewhere.