Just before leaving for Baghdad earlier this month, I spoke by phone to my Iraqi driver Salam, who was recently released from prison.

What he told me haunted me during my visit. It made me question what kind of Iraqi regime will emerge after U.S. troops exit by the end of 2011, and what sort of long-term relationship can develop between Washington and Baghdad.

Salam spent two years in jail on false charges brought by relatives of Shiite militiamen from the Mahdi Army of radical cleric Muqtada al-Sadr. These militiamen, who were killing Salam’s neighbors, were arrested after he tipped U.S. troops. When American soldiers left Baghdad, the killers used contacts inside Iraq’s Shiite-dominated army to get Salam — and his two teenage sons — jailed.

The three were finally freed by an honest judge. But Prime Minister Nouri al-Maliki has now made a political deal with the Sadrists in order to finally form a government, nine months after Iraqi elections. The deal, brokered by Iran, required that large numbers of Mahdi Army thugs – like those Salam fingered — be freed from prison. This deal resurrects a fiercely anti-American group that battled U.S. forces until it was routed in 2008.

With Sadrists on the loose, Salam began receiving death threats. He told me he was going to flee Iraq (to a country that, out of concern for his safety, I won’t name). No one answered when I phoned him in Baghdad.

Maliki, for his part, is still dickering over key government posts with the Sadrists, who hold a crucial bloc of 40 parliamentary seats. Iran obviously influences Sadr, who lives in Iran, as well as other political parties whose leaders troop regularly to Tehran.

U.S. officials profess not to be overly worried about the reemergence of the Sadrists, or Iranian influence. “Iran is inevitably going to be a player, but not calling the shots,” one told me. As a hedge against Tehran, the United States is working to improve ties between Shiite-led Iraq and its Sunni Arab neighbors.

American Embassy officials in Iraq are pleased that Maliki, a Shiite, has given major government portfolios to Sunnis, who did well in the elections and feared they would be excluded. Washington hopes an inclusive government will reduce tensions.

Yet Iranian meddling, and the anti-Americanism it stirs, are bound to affect the long-term U.S. role in the country. There’s been no substantial discussion yet between Maliki and U.S. officials about whether any residual U.S. troops might remain in Iraq, even as advisers, after 2011. Under domestic and Iranian political pressure, Maliki may be reluctant to consider the idea.

“I hope we can start the discussion as soon after (a government is formed) as possible,” Adm. Mike Mullen, the chairman of the Joint Chiefs of Staff, told journalists in Baghdad. “We are by no means out of time, but whatever agreement we are going to reach can’t wait until the end of (next) year.”

Many of the U.S. military’s training functions will be taken over by the vastly expanded State Department operation in Baghdad. It will include an Office of Security Cooperation staffed by military and civilian personnel, including private contractors. Similar offices exist in the U.S. Embassies in Ankara and Cairo.

And the United States’ Strategic Framework Agreement with Iraq calls for expanded cooperation in civilian areas, including trade, education, and culture, with exchanges of students, young leaders, and museum exhibits.

However, in a bad geographical neighborhood, where neighbors are keen to meddle in Iraqi affairs, a strong security relationship between Washington and Baghdad is essential. U.S. troops now mediate between Kurds and Arabs in the north. They train Iraqis to guard against external threats to their territory, including building an air defense network. And they offer visible proof of the continuing bond between the two countries.

Here’s my nightmare: As Americans turn inward, the White House may lose interest in pursuing strong civilian and military ties with Baghdad, and Tehran will fill the vacuum. Secular Iraqis who believed U.S. promises, like Salam, will flee (along with Iraq’s Christians), as Muslim religious parties solidify power. A fractious government will fuel enough violence to make Iraqis yearn for a new dictator.

“Where we are today has been paid for in blood,” a sacrifice shared by Iraqi and U.S. forces, said the deputy U.S. commander in Iraq, Lt. Gen. Robert Cone, last week in Baghdad. We must not allow those shaky gains to be squandered, or swallowed by Tehran.