FALLUJAH, Iraq -- Captain Paul Fowler sat on the curb next to a deserted gas station. Behind him, smoke rose over Fallujah. His company of tanks and Bradley Fighting Vehicles had roamed the eastern third of the city for 13 days, shooting holes in every building that might pose a threat, leaving behind a landscape of half-collapsed houses and factories singed with soot.
''I really hate that it had to be destroyed. But that was the only way to root these guys out," said Fowler, 33, the son of a Baptist preacher in North Carolina. ''The only way to root them out is to destroy everything in your path."
Two days later, Fowler's soldiers and the rest of Task Force 2-2, a reinforced battalion of the Army's First Infantry Division, were rolling back to their bases in cities to the east and north after lending the Marines their muscle to invade Fallujah. The job of heavy armor was largely done, and it was time for civil affairs troops to put the city back together.
''We get to make the mess, and they have to clean it up," Fowler said. ''Their job is a lot tougher than ours."
The battle of Fallujah this month pitted the world's most powerful military force against fighters in tennis shoes wielding homemade rocket launchers. Military planners had decided to use the blunt instrument of heavy armor against an insurgency that they acknowledge cannot be defeated by force alone -- betting that the blow to the guerrillas would outweigh the resentment stirred by the attack. So the job fell to the soldiers from Task Force 2-2, who were accompanied by a Globe reporter.
Afterward, even as they took pride in their speed and sheer destructive power, grunts and officers alike reflected that their handiwork could cause a backlash -- and that the battle has yet to be won in the hearts of Fallujah's people.
''I think it's going to get hotter for a while, when people come back and see what we did," said Specialist Todd Taylor, 21.
US commanders gave the unit a contradictory task: Take back the city with minimal US casualties, but leave it as intact as possible. The latter proved difficult.
To avoid booby traps and ambushes, battalion leaders told the men to fire at houses and buildings before entering them. That made for a trail of destruction. There was no way to know for sure if they were hurting noncombatants, even in a city where most residents had fled.
The battalion commander, Lieutenant Colonel Paul Newell, said US forces could never apply a ''Fallujah method" to other insurgent hubs in Iraq, such as Mosul and Baqubah, where civilian life continues more normally amid rebel activity.
''This is the first time since World War II that someone has turned an American armored task force loose in a city with no restrictions," Newell said. ''Let's hope we don't see it again any time soon."
Asked what lessons he learned for the future of urban fighting, he said, ''Ask me in about a year."
Rebuilding the city and letting residents return while trying to keep insurgents out will be a big challenge, he said. Echoing many of his troops, he said the best chance for a long-term victory is if residents of other cities conclude, ''This is what happens if you shelter terrorists."
That position has drawn criticism from Sunni Muslim leaders and others who say it punishes ordinary Fallujans for the actions of armed bands who took over their city. But those questions were beyond the scope of the battalion's leaders.
At least 53 American soldiers were killed and 425 wounded during the fighting in Fallujah. Four of the battalion's soldiers were killed and 37 wounded, a majority of the casualties they have sustained in eight months in Iraq, which total 10 dead and about 50 wounded.
US officials say more than 1,200 insurgents were killed and that there were few civilian casualties; residents have described several cases of women and children caught in the crossfire.
Days before the invasion began on Nov. 8, Captain Sean Sims, 32, commander of one of the task force's three combat companies, said he was bracing himself for face-to-face fighting bloodier than any he had seen.
''Everybody realizes that it's something that will affect the rest of our lives," he said.
It will be left to other soldiers to weigh that internal toll. Sims died on the sixth day of the battle, leaving a wife and infant. He got out of his armored Bradley to clear a house that had already been cleared once, not knowing gunmen had returned. Shots rang out.
His troops found him in a kitchen cluttered with pots and pans, lying next to a cabinet where someone had drawn a red heart around the word ''Love."
Sunday, Nov. 7
The battle plan seemed as orderly as a game of blocks.
With 24 hours to go before the attack, Newell's staff mapped out a model of Fallujah in a dusty field. Bricks in the dirt represented buildings; the cones of spent shells were mosques. Each platoon leader marched across the bricks to show where his troops were supposed to go, standing astride the model city like Gulliver in Lilliput.
An intelligence officer, Captain Natalie Friel, rattled off the threats: Car bombs. Booby traps. Mines. Rocket-propelled grenades. Fighters who would drop their weapons and run to another stash, or wave white flags and then attack.
Scouts would watch over the city's eastern edge. The tanks and Bradleys would pour in through a breach in a dirt berm along the city's northern edge, making their way south to the main east-west road, shooting their way down main avenues and destroying or seizing suspected insurgent strongholds -- a group of houses called Objective Leopard, a school labeled Objective Coyote.
''The first time you get shot at from a building, it's rubble," Fowler told his platoon leaders. ''No questions asked."
First Sergeant Andrew Richard said insurgents might be wearing the same uniforms as the troops. An Iraqi in a uniform but no flak vest was likely hostile.
''Be safe," Richard said. ''Don't beat yourself up if you shoot one."
Suspected enemy buildings were to be ''cleared by fire" before troops entered. ''No boots on the ground unless you're looking for body parts," Fowler said.
Nonetheless, he said, ''The object is to give Fallujah back to the Fallujans. Not to give them back a pile of rubble."
Monday, Nov. 8
On the first night of the invasion, Fowler's tanks heralded their approach by firing a ''top hat," when several tanks simultaneously let loose on the same target.
In the streets, the clap of insurgents' roadside bombs and rocket-propelled grenades rang out against the pop of machine guns and the crash of tank cannons. Gunners targeted any man who darted across the streets.
With surprising ease, they made it to Objective Coyote and waited for Iraqi troops to catch up. But as infantry troops looked out over a totally dark city, they worried that the best fighters had simply kept their heads down.
Tuesday, Nov. 9
By dawn, the company reached the main east-west road and shot it out with guerrillas holed up in a hospital. They learned that the battalion's senior enlisted man, Command Sergeant Major Steven Faulkenberg, 45, was shot to death when insurgents tried to take the school back from the Iraqi troops.
Wednesday, Nov. 10Guerrillas kept attacking the Iraqi troops as they tried to hold the hospital. A row of houses nearby was nearly demolished. ''We're just cleaning up the trash," Fowler said.
But later, he would fret that his tanks had to return to the same areas time and again, because there weren't enough troops on the ground following them.
''I don't like having to take the same ground over and over," he said at the gas station. ''It's not enough infantry to do the job."
Thursday, Nov. 11
Fowler's company leaders gathered in an auto repair shop. The plan now was to cross the industrial district and head into the southeastern corner of the city, a neighborhood that was a warren of insurgents. This time, the objectives were named after beers: Bud, Lite, Miller.
Soon, the company was knocking down walls to get at insurgents hiding inside factory buildings. ''So much for leaving the place intact," Private First Class Jeremy De Graw said, as the Bradley he rode in shot down a wall and squeezed through the opening.
Friday, Nov. 12
The fight continued into the morning. De Graw's Bradley took a heart-pounding ride over an empty lot that was a suspected minefield, shooting at unfamiliar objects in case they were bombs. The troops were now in the notorious Shuhada neighborhood.
As the sun rose, groups of up to 30 insurgents sprang up from holes, trenches, and walled courtyards. Two soldiers were killed by rocket-propelled grenades: Sergeant James Matteson, 23, a gunner in a Humvee, and First Lieutenant Edward Iwan, 28, second in command of Sims's company. The troops estimated they killed 10 times that many insurgents.
''You don't want to fight an enemy that's fanatical, because their morale is so high," First Sergeant Richard said as tank crews repaired grenade damage. ''But our morale is high, too."
Saturday, Nov. 13
Newell's mobile command post had occupied an empty lot between two half-destroyed houses. Corporal Martin Szewczyk surveyed families' blankets and snapshots strewn on the floor by troops looking for weapons.
''I feel bad," he said. ''These were poor people."
Newell listened to the radio in his Bradley. ''Terminator Six is down," it squawked. The normally unflappable commander winced. Terminator Six was Sims.
Sunday, Nov. 14
Fighting continued as troops cleared every house. Small numbers of fighters could still tie up armored convoys for hours.
But the troops began to sense some rewards. They found piles of weapons. In a house yards from the deadly Nov. 12 attack, they found a mural of the banner of Tawhid and Jihad, a group that has claimed responsibility for numerous bombings and beheadings, and letters military translators said were written by its leader, Abu Musab al-Zarqawi.
Restless in the back of a Bradley, Sergeant John Cunningham, 37, of Boston, said it was ridiculous to label any particular war tactic inhumane.
''People shooting each other is inhumane. Let's find a better way to solve our problems," he said.
Then he added: ''Let's get this over with. The way home leads through Fallujah."
Anne Barnard can be reached at email@example.com.