BAGHDAD, July 18 — After months of lying low, the anti-American Shiite cleric Moktada al-Sadr has re-emerged with a shrewd strategy that reaches out to Iraqis on the street while distancing himself from the increasingly unpopular government.

Mr. Sadr and his political allies have largely disengaged from government, contributing to the political paralysis noted in a White House report last week. That outsider status has enhanced Mr. Sadr’s appeal to Iraqis, who consider politics less and less relevant to their daily lives.

Mr. Sadr has been working tirelessly to build support at the grass- roots level, opening storefront offices across Baghdad and southern Iraq that dispense services that are not being provided by the government. In this he seems to be following the model established by Hezbollah, the radical Lebanese Shiite group, as well as Hamas in Gaza, with entwined social and military wings that serve as a parallel government.

He has also extended the reach of his militia, the Mahdi Army, one of the armed groups that the White House report acknowledged remain entrenched in Iraq. The militia has effectively taken over vast swaths of the capital and is fighting government troops in several southern provinces. Although the militia sometimes uses brutal tactics, including death squads, many vulnerable Shiites are grateful for the protection it affords.

At the same time, the Mahdi Army is not entirely under Mr. Sadr’s control, and he publicly denounces the most notorious killers fighting in his name. That frees him to extend an olive branch to Sunni Arabs and Christians, while championing the Shiite identity of his political base.

On May 25, in his first public Friday Prayer in months, he explicitly forbade sectarian attacks.

“It is prohibited to spill the blood of Sunnis and Iraqi Christians,” he told Shiites in a much publicized sermon. “They are our brothers, either in religion or in the homeland.”

Almost from the day American troops entered Iraq, the mercurial Mr. Sadr has confounded American and Iraqi politicians alike. He quickly rallied impoverished Shiites in peaceful displays of Shiite strength, as had his father, a prominent cleric. When the Sunni Arab insurgency gained momentum, he raised a Shiite insurgency in direct opposition to the American-backed Iraqi government that had excluded him.

His basic tenets are widely shared. Like most Iraqis, he opposes the American military presence and wants a timetable for departure — if only to attain some certainty that the Americans will leave eventually. He wants the country to stay unified and opposes the efforts of those Shiites who have had close ties to Iran to create a semiautonomous Shiite region in southern Iraq.

After his Mahdi militia was defeated in a bloody battle against American forces in Najaf in 2004, Mr. Sadr established himself as a political player, using the votes of loyal Parliament members to give Nuri Kamal al-Maliki the margin needed to win the post of prime minister.

Now that the leadership is in poor repute, Mr. Sadr has shifted once again. The six ministers in the cabinet and 30 lawmakers in Parliament allied to him have been boycotting sessions. They returned Tuesday, but it is not clear they will stay long.

The mainstream political parties in Iraq realize that Mr. Sadr is growing more influential, but appear to be flummoxed over how to deal with him. They see him as unpredictable and manipulative, but too politically and militarily important to ignore.

“He’s powerful,” said Jaber Habeeb, an independent Shiite member of Parliament and political science professor at Baghdad University. “This is a fact you have to accept, even if you don’t like it.”

The latest stance by the more conventional political parties is to keep him at arm’s length. The two major Shiite parties, Dawa and the Supreme Islamic Iraqi Council, along with the two Kurdish parties, have been negotiating to form a new moderate coalition.

Mr. Sadr’s political leaders were told he was welcome to join, but the invitation came belatedly, after the other groups had all but completed their discussions. Mr. Sadr’s lieutenants announced that he had no interest in joining.

Experts in Shiite politics believe that efforts to isolate Mr. Sadr are bound to fail.

“Sadr holds the political center in Iraq,” said Joost Hiltermann, the director of the International Crisis Group’s office in Amman, Jordan. “They are nationalist, they want to hold the country together and they are the only political organization that has popular support among the Shias. If you try to exclude him from any alliance, well, it’s a nutty idea, it’s unwise.”

The mainstream parties talk about Mr. Sadr carefully. Some never mention his followers or the Mahdi militia by name, but speak elliptically of “armed groups.” Others acknowledge his position but are reserved on the challenge he poses.

“Moktada Sadr is one of the political leaders of this country,” Adel Abdul-Mahdi, one of Iraq’s two vice presidents, said in a recent interview. “We disagree on some things, we have differences. We have to work to solve our differences.”

The Sadrists exhibit a quiet confidence, and are pulling ever more supporters into their ranks. “The Sadr movement cannot be marginalized; it is the popular base,” said Sheik Salah al-Obaidi, the chief spokesman and a senior strategist for Mr. Sadr’s movement in Najaf. “We will not be affected by efforts to push us to one side because we are the people. We feel the people’s day-to-day sufferings.”

A number of working-class Shiites reflected that sentiment in conversations about the Mahdi militia and Mr. Sadr. Their relatives and neighbors work both for the Sadr offices and for the militia, blurring the line between social programs and paramilitary activity.

Mr. Sadr’s offices are accessible storefronts that dispense a little bit of everything: food, money, clothes, medicine and information. From just one office in Baghdad and one in Najaf in 2003, the Sadr operation has ballooned. It now has full-service offices in most provinces and nine in Baghdad, as well as several additional storefront centers. In some neighborhoods, the militiamen come around once a month to charge a nominal fee — about 5,000 Iraqi dinars, or $4 — for protection. In others, they control the fuel supply, and in some, where sectarian killings have gone on, they control the real estate market for empty houses.

The Mahdi militia is deeply involved in that sectarian killing. In a vicious campaign in the Amil neighborhood in western Baghdad, once a mixed working-class neighborhood of Shiites and Sunni Arabs, it has driven out many Sunnis and isolated others in a few enclaves.

Young men, said by residents to be part of the Mahdi militia, check every car coming into the Shiite section of the neighborhood. And many mornings, the bodies of several Sunni Arabs are dumped in a brick-strewn lot near the neighborhood’s entrance. Local Shiites routinely claim that the bodies are of foreign terrorists.

However, each community insists that it is the victim of the other. A sniper in the Sunni Arab area shoots at Shiites lined up to buy at a gasoline station that straddles the two communities. That, in turn, is used to justify retaliatory attacks on Sunni Arabs.

Among Shiites, the militia is viewed as their best form of protection from Sunni Arab insurgents. “This is the Mahdi Army standing in our streets,” said Rahman al-Mussawi, 38, a community leader who says he is proud that he still has Sunni Arab neighbors on his block, even though Sunni insurgents almost certainly killed his three younger brothers. They disappeared along a deadly stretch of road south of Baghdad where Shiites have been victims of Sunni extremists.

Mr. Mussawi gestured to the end of the block, where young Mahdi guards in T-shirts checked cars entering the neighborhood: “The Americans chase them away. If the Americans just would leave, then the neighborhood would be quiet.”

The Mahdi Army’s darker side is rarely discussed in Shiite neighborhoods. In Amil, some people fiercely reject any suggestion that the group runs death squads. Others might admit to some problems, but dismiss them as the excesses of a few bad apples.

“Of course there are some wrongdoings done by renegades in the Mahdi Army who deviated from the good and honorable line of the army,” said Mohammed Abu Ali, 55, a mechanical engineer who helps out in the Sadr office in Amil. “We do not approve these wrongdoings and we try to rid of elements in the Mahdi Army.”

Mr. Sadr began his most recent ascent after the bombing of the golden dome of the Askariya shrine in Samarra, sacred to Shiites, in February 2006. It was one of a string of assaults by Sunni Arab insurgents on Shiites that had gone on for more than two years.

Mr. Sadr’s militia began to strike back, supported by Shiites who felt it was their only protection.

Iraqi politicians say Mr. Sadr made another smart move this spring, when he pulled out of the government to protest its refusal to set a timetable for the withdrawal of American troops. Stymied by infighting, Mr. Maliki has yet to fill the posts.

Shortly after a second bombing in Samarra this June, Mr. Sadr called for a mass Shiite pilgrimage to the Sunni Arab city to honor an imam whose body lies in the ruined shrine. Government officials had to plead with him to cancel it to avoid violence. He eventually did, but not until he had made his point: he was a power to be reckoned with.

Qassim Daoud, a secular Shiite lawmaker, says Mr. Sadr has figured out the alchemy to playing the outsider, but having just enough of a place in the government to have leverage.

“He is one of those people who has two legs, one inside the political process and one outside the political process,” Mr. Daoud said. “So, he uses both to attack the process.” (Copyright 2007 The New York Times Company 07/19/07)