In this Oct. 31, 2011 photo, work is underway in Big Bend National Park, Texas on a planned remotely-operated port of entry at the Rio Grande. It would be the first of its kind on the U.S.-Mexico border and provide access to Boquillas del Carmen, Mexico, seen in the distance. (AP Photo/Christopher Sherman)
December 12, 2011 5:35:49 AM PST
By CHRISTOPHER SHERMAN
BIG BEND NATIONAL PARK, Texas - December 12, 2011 --
The bloody drug war in Mexico shows no sign of relenting. Neither do calls for tighter border security amid rising fears of spillover violence.