Indeed, the State Department's latest travel advisory for the Mexican border region reads like the plot of a crime thriller. "Recent Mexican army and police confrontations with drug cartels have resembled small-unit combat, with cartels employing automatic weapons and grenades," it states "Large firefights have taken place in many towns and cities across Mexico but most recently in northern Mexico, including Tijuana, Chihuahua City and Ciudad Juarez. During some of these incidents, US citizens have been trapped and temporarily prevented from leaving the area."