The U.S. Border Patrol could add up to 10,000 agents in the next five years. The training this sometimes-controversial agency requires can seem brutal, and the job can be deadly. So who would sign up for work like this? ARTESIA, N.M. - On Independence Day 2004, Pedro Infante was driving through Mosul, Iraq, manning a 50-caliber gun atop a cargo truck, when an explosion hurled shrapnel into his helmet. A year later, Infante is here in another desert, training for another dangerous and highly politicized job: working as a Border Patrol agent in Southern Arizona, the nation's hot spot for...