In the summer of 2006, Maj. Walt Cooper was convinced that his Special Forces team's work was only contributing to the violence spiraling out of control in Baghdad.

Cooper and his soldiers were training a police battalion that took orders from a radical Shiite militia. "We know that the guys we train are some of the same dudes who are putting bullets in the back of people's heads or going to work on them with power drills," he wrote in a July 2006 e-mail home.

As the months passed, his cynicism and anger grew. "This place is now rotten to the core," he concluded.

A year later Cooper was back in Iraq,