American soldiers have again hit the streets of dangerous neighborhoods in western Baghdad that had been handed over to Iraqi forces, trying to keep a lid on sectarian attacks that have raged since the February bombing of a Shiite shrine in Samarra. The U.S. military has refocused its mission to confront death squads that have tortured and killed hundreds, a tacit acknowledgment that Iraqi troops have not been able to control violence between Shiites and Sunnis on their own. Full Story