Iranian intervention in Iraq would be risky

The closer ISIS gets to the Iraqi capital, and the sacred Shi’ite shrine of the Mosque of the Golden Dome in the city of Samarra, the more likely Iran will feel that it has no choice but to intervene. Iranians, says Philip Smyth, an expert on Shi’ite militias at the Washington Institute for Near East Policy, sees ISIS “as an existential threat to the Shi’ite population of Iraq, and are trying to grab the bull by the horns.” When ISIS’s predecessor, the Islamic State of Iraq, attacked the shrine in 2006 it unleashed a spasm of sectarian violence that resulted in the deaths of tens of thousands of Iraqis of both sects, and left more than four million displaced.

But an Iranian military presence would not only alarm Iraqi Sunnis, it would be a major affront to the U.S.’s Sunni allies in the Gulf, like Saudi Arabia, Bahrain and the United Arab Emirates. “When you start seeing Iranian aircraft, [Iranian Revolutionary Guard Corps] forces on the ground, Iranian advisors training the Iraqi military, it could easily devolve into a regional conflagration,” says Smyth. “It’s not like Riyadh wants to back ISIS, but what are they going to do when they see a mobilization like this, and no other outside force to quell it?”