McALLEN — Another reminder of why we need a secure border emerged this week, as U.S. Border Patrol officials confirmed three Afghan nationals were detained in the Rio Grande Valley - an increasing "hot zone" of cartel invasion and violence against American ranchers. Border Patrol confirmed the detentions, but would not say where or when they occurred. Enrique Mendiola, assistant chief Border Patrol agent for the Rio Grande Valley sector, said that human smugglers see moving people besides Mexican nationals as a "business opportunity." "Average smuggling rates for other-than-Mexican nationals far exceed those of Mexicans and Central and South Americans,"...