In 1968 in South Vietnam, a U.S. infantry battalion was ordered to charge a fortified North Vietnamese Army force 200 yards away over an open field with no artillery or air support. The defenders had every advantage. The Americans started moving across the field just before noon, every man a target. By the time they reached the tree line at the other side of the open field, nearly one half of the 400-man battalion was a casualty. Nine long, agonizing hours afterwards, U.S. artillery units began support fire, although the units remained desperately short of ammunition. The entrapped men saw...