Gun-toting members of the Mexican military are crossing regularly into U.S. territory, where they are partnering with drug cartels and criminal gangs to protect sophisticated smuggling operations, according to Texas sheriffs and lawmakers. Some of the Mexican infiltrators are suspected to have been trained by the U.S. military. U.S. Border Patrol agents and local law enforcement officials operating along the southwestern border have come under attack from the Mexican side in recent months, with automatic gunfire frequently erupting, Rep. John Culberson (R-Texas) told Cybercast News Service. Mexican military units and drug cartels have access to weaponry and communications equipment far...