FORWARD OPERATING BASE HASSANABAD, Afghanistan -- In the middle of a foot patrol Saturday through what may be the most dangerous part of the most dangerous province in Afghanistan for U.S. troops, Staff Sgt. John Nickerson peered through the scope of his assault rifle at a group of Afghan men who were rolling a wheelbarrow toward him. Suddenly, he had to switch gears to the gentler form of counterinsurgency. "Hold," Nickerson said into his hand-held radio, lowering his gun. "We've got some men with a kid in a wheelbarrow trying to get our attention. Where's Doc at?" In the barrow...