While politicians and pundits endlessly debate immigration policy, U.S. Border Patrol agents put their lives on the line to enforce immigration law. In a day's work, agents may catch a load of narcotics, apprehend groups of people entering the country illegally, and intercept a potential terrorist. Their days often include rescuing aliens from death by thirst or murder by border bandits, preventing neighborhood assaults and burglaries, and administering first aid to accident victims, and may involve delivering an untimely baby or helping stranded motorists. As Bill Broyles and Mark Haynes...