When the Army's 1st Armored Division arrived in Iraq 13 months ago, its job was to close out Iraq's past by wiping out remnants of former president Saddam Hussein's armed base of support. Now several of its units are confronting a new threat, Moqtada Sadr, a Shiite cleric who is leading an armed revolt in defiance of U.S. plans to sideline him in a new Iraq.

This shift in responsibility is hitting hard at soldiers who moved into this area south of Baghdad last Wednesday for a short mission to fight Sadr's militia. In the view of many troops in Company A of the division's Task Force 1-36, the old battle, though filled with hardship, was imbued with the optimism of liberation. The new one is tinted by pessimism. Soldiers feel themselves mired in an effort to navigate the indecipherable intricacies of Iraqi politics.

"I just think it's a lost cause," said Spec. Will Bromley, a gunner who sits inside the turret of a Bradley Fighting Vehicle and mans a 25mm cannon whose rounds can blast walls to pieces. "This has become harder than we thought. Getting rid of Saddam Hussein, that's one thing. Getting Iraqis to do what we want is another. It's like we want to give them McDonald's and they might not want McDonald's. They have to want it or we can't give it to them."

Sgt. Jerry Sapiens, a specialist in nuclear, biological and chemical warfare, suggested there was no end in sight. "We're in the baby-sitting phase and my question is, how long can we baby-sit for the Iraqis? We want the Iraqis to change, to be like us, and to do this we will have to be here forever."

"The enemy is not the same as before," said Spec. Matthew Aissen, a medic. "I fear that people who use religion as a power point are taking over the place. It's a power struggle. Our weak point is they think we are evil and we're not so popular, so we become part of the mess."

The 1st Armored Division was supposed to be out of the powdery sand, 100-degree heat and explosive danger of Iraq a month ago. After a year in the country, they were scheduled to be back in green and placid Germany, their home base.

During its tour, Company A has seen all sides of the post-invasion phase of the Iraqi conflict. It was originally tasked to safeguard Baghdad neighborhoods, fight insurgents and crime, uncover arms depots, defuse roadside bombs and oversee reconstruction projects.

Duty in Iraq was scheduled to end in April, but in a surprise decision, the Pentagon ordered the 1st Armored Division to stay on for another three months. The disappointment was evident among many of the soldiers here, and has sharpened their doubts.

Capt. Andrew Lomax, Company A's executive officer, was scheduled not only to return to Germany, but also to end his Army service. He now worries that when he enters his post-service period as a member of the Army Reserve, he could be called back to active duty at any time. "Some of us need to make life plans. We're obviously short of forces in Iraq. Suppose the country just wants to split apart? Can we live with that? Or another dictator comes? Are we going to fix that? There are plenty of troublemakers and Iraqis who tolerate them. You could have units here forever," he said.

The soldiers have been told that Sadr and his Mahdi Army represent only a small fraction of Iraq's Shiite Muslim majority. Yet ripping Sadr posters off the walls of villages in the south is proving at least as daunting a task as tearing down the once-ubiquitous portraits of Hussein.

Some soldiers are convinced that political considerations might undermine tactical needs. For instance, Task Force 1-36 came to Karbala to invade the center of the city and drive out Sadr's militia. That complex operation was cancelled, but during the planning, commanders were told to limit the kind of munitions fired at either the Abbas or Hussein shrines in Karbala, the city's gold-topped Shiite mosques.

If someone was spotted shooting from the mosques, soldiers were to return fire with nothing larger than 7.62mm bullets, machine-gun ammunition.

Commanders fear that damaging the shrines would inflame Shiite public opinion and bolster support for Sadr. Lt. Col. Charles Sexton, commander of the 1st Battalion, 36th Infantry Regiment, explained that it was "doctrinally correct" to declare specific "no-fire areas." He noted, however, that nothing would preclude a soldier's "right of self-defense" even if it meant using a high-powered weapon.

To Sgt. Maj. Robert Cormier, such decisions could complicate the soldiers' response to danger. "We definitely have political constraints. We have to watch that very closely," he said.

Cormier, a 19-year veteran, characterized as unwise a recent deal that ended heavy fighting between U.S. Marines and insurgents in Fallujah, a Sunni Muslim stronghold for Hussein loyalists. After intense fighting last month, Marine commanders brought in former officers of Hussein's army to take charge there. The city has since been quiet, yet Marines continue to take casualties in nearby areas, mostly from roadside bombs.

"This was a defeat for the Marines," Cormier said. "They didn't resolve the problem."

Task Force 1-36 was dispatched to Karbala this week to reinforce another 1st Armored Division unit that has been battling Sadr militiamen. American officials contend that the cleric presents a threat to U.S. designs to transform Iraq into a democracy. His uprising has engendered six weeks of turmoil in a half-dozen Shiite cities in the south and his forces continue to dominate two cities, Najaf and Kufa. The Mahdi Army controlled central Karbala until this week, when its fighters suddenly disappeared from the streets.

U.S. commanders want to end the violence before the planned transfer of limited authority to a new interim Iraqi government on June 30. Pacifying the Shiites is key; they make up about 60 percent of Iraq's population and were relatively receptive to the U.S. invasion last year that toppled Hussein. In central Iraq, tens of thousands of American troops are also bogged down trying to put down a year-long rebellion by Sunni Muslims.

In conversations with Company A soldiers, pessimistic outlooks appear to predominate, although some express positive views on the direction of the occupation. Frequently, opinions varied according to rank. The higher the rank, it seemed, the greater the tolerance for uncertainties in Iraq. The more likely a soldier was to make a career of the Army, the deeper his expressions of enthusiasm and the more muted his criticism.

Lt. Col. Sexton, the battalion commander, is aware of the doubts and complaints of some of his troops, but regards them as misplaced. Overthrowing Hussein and hunting down Shiite rebels are two sides of one mission, he argues. "It's all for the same reason, to build a democracy and to better Iraq. The war is the same," he said. "If what we do gives Iraqi citizens instead of armed mobs the chance to make their own decisions, that's what's important."

The extension of the 1st Armored Division's tour of duty is an acceptable necessity, Sexton indicated. "Is it a question of planning? I don't know. If it keeps our brothers in other units safe, then it's worth it. If staying a little longer helps, then it's worth it. We would expect the same of others," he said.

Capt. Buckley O'Day, the commander of Company A, said he was "willing to stay another three years" to stabilize Iraq. "The enemies of the future are the enemies of us. Making Iraq a democracy can change the whole Middle East," O'Day said.

O'Day and Spec. Bromley, the Bradley gunner, share similar stocky builds and small home towns near Dallas, but their views on the prospects for success in Iraq are continents apart. On Saturday evening, as they were loading up for a nighttime operation in a small village, the pair exchanged views. Sweating under the weight of flak jackets, helmets and rifles , the two comrades gathered close, a gesture usually reserved for the arrival of somebody's latest issue of Maxim magazine.

"Last May, possibly, there was a chance for this thing to succeed. People were happy. Then we started arresting people" for carrying ammunition, said Bromley, referring to operations to disarm Iraqis in Baghdad. "It's been easy for enemy recruiters. They just wait for something bad to happen, like if someone shoots up a family. They just have to wait, and the recruits come in."

"They don't have to like us, they just have to want to succeed and make Iraq better," O'Day responded.

"The Iraqis don't trust us," Bromley went on.

"That's why we can't abandon the fight now," O'Day shot back.

The debate ended with an order to roll the Bradleys out of the dusty lot. The objective was the town of Husseiniya, where, Company A was told, insurgents and weaponry were sheltered in a cluster of houses.

Task Force 1-36 had traveled to Karbala from Baghdad last Wednesday. The trip was uneventful. In Shiite towns along the route, some bystanders gave friendly thumbs-up signs, others gawked and still others glared. One boy in a bicycle called out, "Go back to where you came from."

At one point, a young sergeant from Company A dismounted from his Bradley to pull down a poster of Sadr that decorated a pylon at the head of a bridge. Weighed down with a heavy rucksack and M-16 rifle, the soldier was unable to leap high enough to grab it. "Just out of my reach!" he said. "Just out of reach."

The phrase turned out to describe the raid on Husseiniya as well. It was a bust.

The column of Bradleys reached the hamlet late at night. "Ramp down!" came the order from O'Day, and a Bradley's back door swung to the ground like a drawbridge. Date palms appeared in the pale fluorescent lights from silent houses. Market stalls built of mud lined the dusty road. A dog yapped from afar.

Infantrymen scrambled from the Bradleys. The first report from a forward patrol crackled across O'Day's radio. Just a woman and 14 kids here, the voice said.

And so it went: no rebels, no weapons. "Looks like we got some bad information," O'Day said.

The operation should have ended quickly, but early on, one Bradley had rolled into a canal. It sank until only its turret stuck above the water line. Soldiers struggled out the back hatch and flailed to reach the shore against the force of the current and the weight of their flak jackets. They all escaped unhurt. "I can't even swim," said Spec. Edison Ybay. "I learned quick."

Not long after, another Bradley that was going to check out a car spotted on a side road slipped into a shallow irrigation ditch. The soldiers inside waded out through knee-deep water.

It took about six hours for big, armored cranes to arrive and extricate the pair of stuck fighting vehicles.

The troops detained 13 Iraqi men, none of whose names matched those on a list of suspected insurgents provided to the soldiers. Nonetheless, the detainees were kept bound with plastic handcuffs for the entire 12-hour operation. The experience left the villagers unhappy. "You know, we used to like the Americans when they first came. How can we like this?" asked Kamel Alawi, one of the detainees.

Sexton told the Iraqis that any property damage -- Bradleys burst through some walls marking off date groves to get to the houses -- would be compensated. He concurred with O'Day that the intelligence leading them to Husseiniya was faulty. He had sensed something was wrong early on, and told Bradley drivers not to ram any of the houses in efforts to ease soldiers' entry.

"It just didn't smell right," he said explaining that decision. "If we had breached the walls, we would have had dead children. I'm just glad no one got hurt and we didn't have any drowned soldiers, either. Things could have been a lot worse."

The unit returned to the barren field in Karbala early Sunday, then the same morning to their base in Baghdad to await another call.