In towns along the United States-Mexico border, a battle is raging between drug cartels and the Mexican government that has left thousands of innocent civilians and Mexican police officials dead. A galvanizing moment occurred on May 8, when assassins shot and killed Edgar Gomez, Mexico's top cop and an anti-cartel crusader, as he exited his home north of Mexico City. Gomez is just one of 6,000 Mexican government officials and police officers...