Tehran’s master of clandestine operations, Qassem Suleimani, could hold the key to Iraq’s future—if he were not so busy back in Iran.

The text message was cryptic and sent through an intermediary, but its spookiness has become legendary among the Americans tasked with trying to stabilize Iraq. The moment was May 2008, and once again all hell was breaking loose. Shiite militias had gone to battle against each other. The fighting threatened to spread to Baghdad. Gen. David Petraeus and Ambassador Ryan Crocker were scrambling to find somebody to broker a truce. Then the text message was passed to the American commander. “General Petraeus,” it began, “you should know that I, Qassem Suleimani, control the policy for Iran with respect to Iraq, Lebanon, Gaza, and Afghanistan.” Within days it was Suleimani who brokered the truce.

What surprised Petraeus and Crocker was not the Iranian’s role. They knew that already. It was the blunt confidence with which Suleimani stated it. As the head of the infamous Quds Force, he commands all the Iranian Revolutionary Guard Corps (IRGC) operations outside Iran’s borders—whether covert, overt, or outright terrorist. In the fractious politicking almost certain to follow Iraq’s parliamentary elections on Sunday, this 53-year-old Iranian general could pull the strings that make or break the new government in Baghdad.

Long before America’s troops occupied Iraq, Suleimani’s forces occupied the shadows. In the buildup to the U.S.-led invasion, he was the go-to guy for much of the Iraqi Kurdish and Shiite opposition to Saddam Hussein. Suleimani’s networks of agents, collaborators, military advisers, client militias, and secret informers give him a degree of power that is difficult to gauge, but it often seems proconsular: “I, Qassem Suleimani,” his text read, like an emperor’s decree. And his real message in 2008 was that he could turn up the heat, or turn it down, at will.

Crocker often used to tell his colleagues that what Suleimani probably wanted to do in Iraq was to “Lebanonize” it. The idea would be to build up as many networks and agents in Baghdad as Iran has in, say, Beirut, so that it could create a crisis—and then solve it, at a political price. As Petraeus described it, Suleimani might say, “We’ll stop the crisis immediately, but of course, you know, we’d like to have one more vote in the council of this and that.” A talented extortionist knows how to set a price that will be met. Through the accretion of such little victories, the Iranians can eventually gain a veto over everything from economic policy to foreign alliances. In the case of Iraq, they also want to make sure that Baghdad will never again challenge them as a regional power.

But today Suleimani doesn’t seem to be paying as much attention to Iraq as he once did. For the last nine months, ever since apparent election fraud in Iran sparked mass protests and continuing unrest, the head of the Quds Force has been drawn back into the treacherous politics of his own country. And what he tries to do in Iraq—indeed, the success or failure of its democratic experiment—may well be a factor of his success or failure in Iran.

Petraeus, who painted this picture when speaking in January to the Institute for the Study of War in Washington, said the unrest following “the hijacked elections” in Iran last year has forced Supreme Leader Ali Khamenei to rely on the IRGC and its Quds Force internally as well as externally. “That has enabled them to then expand their already considerable influence beyond just the security arena, but ever more greatly into the economic arena and even into the diplomatic arena,” said Petraeus, who now heads the U.S. Central Command, the military body focused on the region.

According to people who have followed Suleimani closely and prefer to remain anonymous, the spymaster and many other senior figures in the Quds Force actually supported the presidential challenger, Mir Hossein Mousavi, against incumbent president Mahmoud Ahmadinejad, the Supreme Leader’s anointed favorite. But because of Suleimani’s record fighting the regime’s enemies abroad, he still has Khamenei’s confidence, and he has a demonstrated range of skills, whether persuasive or coercive, that are useful in squelching protests and more subtle kinds of dissent.