Homeland Security Secretary Janet A. Napolitano (riding fifth horse from left) tours the U.S.-Mexico border with Border Patrol agents in the Coronado National Forest near Nogales, Ariz., in October. Starting in January, the force of 1,200 National Guard troops at the border will be reduced to fewer than 300 at a cost of about $60 million. (Associated Press)

Homeland Security Secretary Janet A. Napolitano (riding fifth horse from left) tours the U.S.-Mexico border with Border Patrol agents in the Coronado National Forest near Nogales, Ariz., in October. Starting in January, the force of 1,200 National Guard troops at the border will be reduced to fewer than 300 at a cost of about $60 million. (Associated Press)