Zalmay Khalilzad, Washington's new envoy to Iraq, is on his way to a meeting when an unidentified car pulls in front of his convoy. Bad idea. One of the ambassador's armored escorts quickly rams the vehicle off the road, leaving a dazed and bloodied Iraqi driver yelling for help. A barrel-chested security guard riding shotgun in Khalilzad's car turns to explain: an errant vehicle in Iraq, he says, can easily be a suicide bomber. "This is not the place to pull out in front of a convoy."

The ambassador doesn't stop for much. Minutes later, wearing pinstripes and a flak vest, Khalilzad greets several robed clerics from Iraq's largest political organization, the Supreme Council for Islamic Revolution in Iraq, or SCIRI. With the deadline for a final draft of the Iraqi constitution just days away, Khalilzad is hoping to break a deadlock that has arisen over the critical issue of federalism. But he needs Abdul Aziz al-Hakim, SCIRI's leader, to agree.

Bantering with the cleric in Farsi, the language of Iran, Khalilzad jokes about a recent sandstorm. Hakim laughs. "All your technology can't solve the weather," he chides. "We're going to have to go to the mosque to pray." Khalilzad chuckles, but only briefly. Switching to English, his demeanor stiffens and he leans in close. Time for a compromise is running out, he tells Hakim. Then he lays out some options. "If you want to get agreement from the Sunnis, you have to be specific in the way I describe," he says. "Those are the realistic choices."

Khalilzad, 54, has few illusions about what's at stake in Iraq. Fresh calls for U.S. troop withdrawals and a growing criticism of the Iraq war have given his job new urgency. Failure, or even undue delay in reaching national consensus among Iraqis, could mean disaster--not just for Iraq, but for the United States. "There is a danger that if we don't [build Iraq] we're going to have a civil war," Khalilzad told NEWSWEEK at his house inside the American-run Green Zone. "Iraq's success is our success, and Iraq's failure is our failure."

Can Khalilzad succeed where others have not? He brings to Iraq a unique set of talents and experience. Zal--as he's called by American and Iraqi friends--is a veteran of two previous Republican administrations, and has very close ties to the current White House. He's a Muslim--an Afghan-born American with a reputation for being able to work a crowd of turbaned sheiks at least as well as he works a meeting of Washington suits. And he comes to Iraq directly from a stint as the president's special representative to Afghanistan. "He's truly an operator," says Col. David Lamm, who served as chief of staff to the U.S. military commander in Afghanistan. "He could interpret each side to the other. He understood the concerns and needs of both."

Khalilzad was born in northern Afghanistan in 1951, and he was educated at a British high school in Kabul. He went to college at the American University in Beirut, where he picked up workable Arabic, and he got his Ph.D. from the University of Chicago in 1979. By the mid-'80s, he was a policy planner in Reagan's State Department, where he urged that America arm the mujahedin resistance in Afghanistan with Stinger antiaircraft missiles--the war-winning weapon, it turned out. During the first gulf war, he served in the Pentagon, and when Bush 41 was contemplating a ceasefire, he was a key voice in arguing that Defense should agree. It was Khalilzad who, at an important meeting, pushed the consensus view that Iraq would fragment if Baghdad fell. Now that Bush 43 has orchestrated such a strike, Khalilzad is tasked with picking up the pieces.

For the past two years, he's been the clean-up guy in Afghanistan. Known there as the "viceroy," he was extremely close to President Hamid Karzai. Khalilzad was particularly adept at navigating Afghanistan's complex web of ethnic and tribal politics while also fending off dubious initiatives from Washington. When the Pentagon wanted to wipe out opium production by aerial spraying, which seemed like a good idea from 10,000 miles away, Khalilzad argued that without providing farmers a viable alternative, the campaign would boost recruitment for the Taliban and lead to increased violence. He succeeded in nixing the idea.

NEWSWEEK got a glimpse of his methods recently, accompanying the ambassador on a frenzied round of talks with Iraqi leaders in the run-up to the missed Aug. 15 deadline for a new constitution. His most important asset, perhaps, is his ability to lobby and debate like an insider. When Khalilzad peppers his conversation with the Arabic invocation for God's blessing--inshallah--it doesn't seem like a forced courtesy. "The fact that I can argue with them about the Qur'an, I can get into hermeneutical analysis of the text with them... I think that helps," he says.

Khalilzad is trying to repeat, in furiously accelerated fashion, the strategy he applied in Afghanistan. He even uses the same vocabulary. This has raised hackles. When Khalilzad talked of the problems of "warlordism," critics countered that Iraq doesn't have Afghan-style warlords. But he sees Moqtada al-Sadr and other militia leaders as playing a similar role. He now wants to repeat what he did in Afghanistan, where he cajoled the warlords--by a mixture of promises, military pressure and cash--to enter the political process. Some Iraqis, however, worry about American meddling. "We know he was interfering too much in the details [in Afghanistan]," says Jalal Addin al-Sagheer, a prominent Shiite. "We're afraid he might repeat that pattern here."

But for now, his most pressing concern is the insurgency--and how to find a political solution. The son of a Sunni father and a Shiite mother, he's determined to deepen ties with Sunni leaders, and to bring at least some of the insurgents into the political process. "We should use the military, but intelligently," he says, meaning in ways tailored to support the political process. "Each [Iraqi] has family and a tribe and we have to be very careful not to create circumstances so that 10, 15, 20 years down the road, they seek revenge." It may be too late for that, but at least some Iraqis like his attitude. Talal al-Gaaod, a prominent Sunni businessman from the restive Anbar province, says, "He should have been here from day one."