In the wake of 9/11, the mission of the Border Patrol has been redefined, with emphasis shifting from stopping the flow of drugs and illegal immigration to the critical mission of protecting our vast borders from terrorist infiltration. Agents guard some 8,000 miles of U.S. borderlands using helicopters, four-wheel-drive trucks, motorcycles, ATVs, and snowmobiles, as well as patrolling on horseback, on bicycle, and on foot. These men and women possess...