Haidar Abbas was peddling produce amid the flies and dust of Sadr City, Baghdad's vast Shiite Muslim slum, and discussing Moqtada Sadr, the firebrand cleric whose family name the neighborhood bears. As Abbas spoke, his son Bilal, 16, began to dance a little jig.

"Moqtada, Moqtada," the boy chanted as a crowd of other ragged youths approached to join in. "Moqtada is right. We follow Moqtada. We die for Moqtada."

Branded by the Bush administration as a criminal and a thug who has minimal support among Iraq's Shiite majority, Sadr is viewed very differently from the garbage-carpeted streets of Sadr City. Here, the brash leader of an eight-week-old Shiite revolt is seen as a leading voice of the poor, a patriot fighting foreign occupation and the heir to a tradition of speaking out against injustice and tyranny. His tactics may be foolhardy, his militia might get crushed, but the message he carries reverberates deeply in Iraqi society and will not easily go away, Iraqi observers and common citizens argue.

"I don't like Moqtada personally. Look at what he's done -- gotten a lot of people killed by sending them out against American tanks," Abbas said. "But of course what he says, it's true. What have the Americans brought us? We are worse off than ever. Moqtada wants them out, and who can argue with that?"

For nearly a year, Iraqi Shiites largely welcomed the U.S. invasion and tolerated the occupation. But Sadr, his followers and his clandestine militia were an exception. As early as last June, Sadr was denouncing delays in elections and abuses by occupation forces -- protests that more popular mainstream Shiite clerics did not raise until last fall. As Shiites became increasingly disillusioned with U.S. rule in Iraq, Sadr's isolated complaints became mainstream opinion.

In April, when Sadr resisted U.S. demands that he turn himself over to an Iraqi court on charges related to the murder of a moderate cleric last year, he and his Mahdi Army militia staged a revolt that drew thousands of U.S. troops to the Shiite holy cities of Najaf, Kufa and Karbala.

American officials say U.S. forces have killed about 1,500 Sadr militiamen in eight weeks of fighting and that his militia is near collapse. Though the Mahdi Army, with its assault rifles and rocket-propelled grenades, has been outgunned by U.S. soldiers in Bradley Fighting Vehicles, Sadr has survived and his stature has grown.

"This offensive against Sadr has made him bigger than ever before," said Adnan Ali, a top official of the Iraqi Red Crescent Society, the Muslim equivalent of the Red Cross.

"Sadr emerges from this as a national political figure who will have to be dealt with," said retired Gen. Ali Shukri, a top adviser to the late King Hussein of Jordan with long involvement in Iraqi affairs.

U.S. officials have become aware of Sadr's growing appeal. According to a U.S. official who has seen the figures, an opinion poll sponsored by the Coalition Provisional Authority that came out in mid-May found that Sadr was the second most popular figure in the country after Grand Ayatollah Ali Sistani, the Iraqi Shiites' supreme religious leader.

Ibrahim Jafari, who heads the large Shiite Dawa party and has no sympathy for Sadr's stand or tactics, nonetheless said in an interview: "He is seen as a son of Iraq who represents feelings of injustice. It was a mistake to try to push him out."

Last week, Shiite mediators brokered a cease-fire between Sadr and the occupation forces. But there has been no sign that he has moved to fulfill his promise to pull his militiamen off the streets, and heavy fighting Wednesday in Kufa signaled the collapse of the deal.

The gap between American and Shiite perceptions of Sadr reflects a lack of understanding of the complexities of Shiite religious, political and economic life, Iraqis say. Sadr benefits from the deep reverence that Iraqi Shiites still feel toward his father, Grand Ayatollah Mohammed Sadiq Sadr, who was slain in an ambush along with two of his sons in 1999. Shiites suspect that Saddam Hussein, then Iraq's president, ordered the murders. A cousin, Ayatollah Mohammed Baqir Sadr, regarded by many as the foremost Shiite thinker of his generation, was killed by Hussein's security forces in 1980.

Sadr's father had a style of preaching that set him apart from traditional religious figures. He directly addressed social and economic needs. When he spoke to students and followers, he used the Arabic term of endearment, habibi. He took risks by criticizing practices of the Hussein government. Once, he made a speech calling for the release of prisoners. Another time, he called on government officials to come to his office in Najaf to apologize to Iraqis for the cruel treatment of the population.

Moqtada Sadr delivers his father's message with a street style that horrifies traditional Shiites but attracts the young underclass. By all accounts, he speaks haltingly, sometimes in incomplete sentences. He uses slang, a habit that many Iraqis consider unseemly in a cleric. And at only 31, Sadr is considered by many Iraqis to be too raw to play the role of preacher to the nation.

But to Sadr's followers, his shortcomings are less relevant than the prestige afforded by his heritage.

"No matter how dumb he is, many Iraqi Shiites will follow him and respect him because of his father," said Shukri, the Jordanian.

"Iraqis are loyal to those they love," said Mustafa Nassiri, a sociologist. "They loved his father, so they love the son."

Hassan Ali, a porter at a Sadr City market, gave a blank look when asked whether Sadr's lack of eloquence was a drawback. "You mean the way he talks? Who cares? Sadr is the strongest, the bravest. He's for justice," Ali said, then added, "He's Iraqi."

For his loyalists, the fact that Sadr is Iraqi-born is a plus. By contrast, Sistani is Iranian by birth. Sadr plays heavily on patriotism. Among the multitude of Sadr posters in Sadr City is one that shows his bearded face along with his father's on the red, white and black Iraqi flag. The flag also flies over his Sadr City offices. There is no such banner atop Sistani's office in Najaf.

But Sadr City is far from unanimous in its support of Sadr. It is a jumbled neighborhood that has decayed and grown ever more cramped with the influx of Iraqis looking for work in the capital. On the south end of the enclave, where better-off Shiites live, there are posters extolling Sadr's virtues. But deeper into the slum, the posters of Sadr, his fingers thrust aggressively into the air, grow in number. At the northern fringes, hardly a wall does not bear his portrait.

Nassiri, the sociologist, said Sadr's main support lies among rural migrants who came to Baghdad and other cities over the past several decades to better their lives -- only to find cramped housing, overflowing sewers, an inadequate water supply and no jobs. The elder Sadr cultivated Iraq's rural Shiite poor. By contrast, the core followers of Sistani and other mainstream leaders include the Shiite merchant class, which is uncomfortable with Sadr's populist message.

The Abu Ibrahim family in north Sadr City comes from Amarah in Iraq's deep south. Their small, flat-roofed house contains a dozen people. The husbands of four daughters are all jobless. There is no running water and no electricity. Black, putrid sewage laps at the front door. The family lives on rations provided by the occupation authority.

In the family's living room, the sole piece of furniture -- a flimsy armoire -- is decorated with six Sadr portraits. "We love Moqtada and we put him atop our head," said a jolly 6-year-old named Mohammed.

Um Ibrahim, the matriarch of the family, said wearily: "You can see, all the very poor, we support Sadr. We are not few. We are many. The majority are poor. And he is the only one who looks out for us. He is simple. He is one of us. He is Iraqi."

Nassiri said Sadr has particular appeal among young, unemployed Iraqis who have little to lose and are impatient not only with the occupation but with the willingness of many mainstream Shiite leaders to go along.

"Iraq is a pyramid with poor youths at its base," Nassiri said. "They feel victimized by Iraq's past and ignored by its present. Sadr represents them, and they cannot be shoved aside, neither by the Americans or Iraqis, when they come to power."

In effect, Sadr's revolt is not only anti-American but also anti-establishment. He has upset the traditional notions of Shiite religious hierarchy, in which influence rests with a handful of aged wise men. Graffiti on several walls in Sadr City attack Sistani as well as officials of the Supreme Council for the Islamic Revolution in Iraq, a political party that has cooperated with the occupation. In Shiite terminology, Sistani and the party represent the "silent seminary" that shies from speaking out directly on social or political issues. Sadr's father, and now Sadr, represent the "speaking seminary," which tackles such issues head-on.

"The Silent Seminary is traitorous," says one message scrawled on a wall near the cleric's Sadr City office. "Woe to the Silent Seminary," says another a block away.

"We are losing patience with the silent school. They are saying we are criminals. That really makes us angry," said Karim Manfi, a preacher at Sadr City's Hikma Mosque, which Sadr's organization controls. "The real problem is they are afraid of the Sadr school of thought. While we are dying, Sistani says nothing. He does not feel like we feel. The silent seminary cannot represent us."

Manfi said the tactics of Sadr's militia, which are to fight U.S. forces openly and control neighborhoods, reflect the belief in a confrontational approach as well as adherence to the Shiites' tradition of martyrdom as the path to purity.

"We do not set off roadside bombs and hide. That is not our way," Manfi said. "Nor do we dissimulate. That is also not our way." He noted that at least 100 militia members have been killed fighting U.S. troops in Sadr City. U.S. commanders have expressed surprise and bewilderment at the willingness of Sadr's followers to die.

Manfi's brother, Ahmed, who was jailed for four years for protesting the assassination of the elder Sadr, said that by going into the streets to battle the Americans, Sadr's followers were trying to wake up Iraqis.

"Moqtada is not silent, and we cannot hide," he said. "We must be brave."

Posters of Shiite Muslim cleric Moqtada Sadr, sometimes including images of his slain relatives, are common in the streets of Baghdad's Sadr City slum, named for the cleric's revered father. Sewage flows in the streets of Sadr City, Baghdad's large Shiite slum, where cleric Moqtada Sadr has wide support.A girl stays near her mother in the two-room Sadr City apartment they share with 14 other people. Overcrowding is among the neighborhood's problems.