BIG BEND NATIONAL PARK, Texas (AP) -- The bloody drug war in Mexico shows no sign of relenting. Neither do calls for tighter border security amid rising fears of spillover violence. This hardly seems a time the U.S. would be willing to allow people to cross the border legally from Mexico without a customs officer in sight. But in this rugged, remote West Texas terrain where wading across the shallow Rio Grande undetected is all too easy, federal authorities are touting a proposal to open an unmanned port of entry as a security upgrade. By the spring, kiosks could open...