Martin Dempsey, the Army general who's now chairman of the Joint Chiefs of Staff, was a division commander when he got to Baghdad in 2003 and climbed into a Humvee for his first trip off base. "I asked the driver ... who he was (and) where he was from," the general remembers, "and I slapped the turret gunner around the leg and I said, 'Who are you?' And she leaned down and said, 'I'm Amanda.' "And I said, 'Ah, OK.' So female turret gunner protecting division commander." One of the things that makes a good commander is the speed...