A former CIA operative described Qassem Suleimani, the head of Iran’s Quds Force, as the “most powerful operative in the Middle East today.” Fars News Qassem Suleimani, the head of the Qods Force, the foreign arm of Iran's Revolutionary Guards Corps, is leading the Iraqi reaction to a radical Islamist group's takeover of much of the country, according to a senior Iraqi official quoted by The Guardian.

"Who do you think is running the war? Those three senior generals who ran away?" the unnamed official asked The Guardian's Martin Chulov. "Qassem Suleimani is in charge. And reporting directly to him are the militias, led by Asa'ib ahl al-Haq."

Asaib ahl al-Haq (AAH) organization is one of several Iraqi groups that serve as instruments of Iranian policy through the region, as University of Maryland researcher Philip Smyth explained in a policy brief for the Washington Institute for Near East Policy earlier this week.

Specifically, it is a Shiite militia and Iranian proxy in Iraq that deployed fighters to the Syrian theater to support the regime of Bashar Assad. But Smyth writes that AAH fighters have now been recalled to Iraq to combat the Islamic State of Iraq and the Levant (ISIS), the al-Qaeda castoff that took over vast stretches of the country's oil-producing north last week.

"Many of the Shiite Islamist forces fighting in Iraq operate as part of Iranian proxy groups that have been attached to [Iraqi Security Forces] and Iraqi army units," Smyth wrote. "Some even operate as a direct part of these official Iraqi military forces."

So it would make sense if Suleimani were calling the shots inside of Iraq itself. He's responsible for arming and organizing sectarian militias that are semi-integrated into the official security apparatus in parts of the country. And he was in Baghdad meeting with Shiite parliamentarians not long before things escalated.

It's a place he knows well. In his profile of Suleimani for The New Yorker last year, Dexter Filkins recounted how the Qods Force chief used his connections in Iraq to play the Americans, Sunni terrorists, and Shiite proxy militias off of one other during the U.S.'s military presence in the country. He even visited Baghdad's Green Zone:

Throughout the war, [Suleimani] summoned Iraqi leaders to Tehran to broker deals, usually intended to maximize Shiite power. At least once, he even traveled into the heart of American power in Baghdad. “Suleimani came into the Green Zone to meet the Iraqis,” the Iraqi politician told me. “I think the Americans wanted to arrest him, but they figured they couldn’t.”

The pro-Iranian Iraqi government that ensured the U.S. military would leave the country in 2011 is essentially Suleimani's creation as well.

Suleimani is deeply invested in keeping together the network of influence and control that he spent much of the past decade building in Iraq. Still a major open question: whether he'll have the U.S. on his side in his efforts.