But beating is strictly forbidden by the United States Army’s Field Manual, as well as American and Iraqi laws. When the Americans learned about the beating, they were quick to condemn it.

The use of torture by American soldiers and contractors at Abu Ghraib only compounded Iraqi hatred of Americans and further undermined American moral claims in Iraq. It also produced little valuable information. Most experts, including in the military, say they believe that coerced confessions are an unreliable way to learn about enemy operations because people being tortured will often say whatever they think it will take to stop the pain.

This joint security station in Ghazaliya opened on March 15, about a month after the latest increase in American troops began. The station, inhabited by about 70 soldiers of Company D of the Second Battalion, 12th Cavalry, and their Iraqi counterparts, is named for Specialist Robert Thrasher, a member of the unit killed by sniper fire on Feb. 11 when the company was scouting for a station site.

Thrasher, as the station is known, sits in the southern part of Ghazaliya, one of the roughest areas of western Baghdad. In the northern part, Shiite militias, led by the Mahdi Army, have been driving out Sunni Arabs through raids and assassinations. Sunnis have pushed Shiites out of the southern part.

Sewage pools in the streets. Water and electricity are almost nonexistent, and fewer than half the houses are occupied. The neighborhood graffiti broadcasts the presence of an active insurgency: “Long live Abu Hamza al-Muhajar,” reads one scrawl, referring to a local insurgent leader.

The outpost’s location, along one of the main arms smuggling routes from Falluja, was chosen because it was next to a litter-filled lot that was a dumping ground for bodies. When they first arrived, the American soldiers found 30 bodies there, among them women and children.

Now it is rare to find more than one or two, said Captain Fowler, who keeps photos of every one on his computer as a reminder of how much worse it was before his company took up residence. He can also point to other signs of progress: children have begun to play outside again, and women walk to the market.