"Tell Lieutenant Jacobson to meet us there with a bag of money," Lieutenant Colonel Joe Gandara shouts into his headset as his Humvee rumbles down the highway into Dora, a Baghdad district synonymous with violence. Gandara, a stocky 42-year-old, was heading to pay a group of children who had volunteered to pick up some of the rubbish that blights Dora, where insecurity has kept away the garbage trucks. The predominantly Sunni district south of the Tigris River has been ravaged by the sectarian bloodshed that pits Sunnis against Shi'ites, killing scores in Baghdad every week. Until last Monday that is,...