IN-CHIEF. "BORDER SECURITY, POLICING, IS NOT THE PRIMARY ROLE OR MISSION OF THE UNITED STATES MILITARY," THE OFFICIAL SAID. SEN. JOHN CORNYN, A TEXAS REPUBLICAN, SAID THE PENTAGON OUGHT TO BE BACKING UP THE DEPARTMENT OF HOMELAND SECURITY ALONG THE BORDER. "WE CAN AND MUST DO MORE TO MAXIMIZE MILITARY ASSETS ALONG THE BORDER UNTIL THE DHS HAS ADEQUATE ASSETS TO ENSURE OUR BORDER SECURITY," HE SAID IN A STATEMENT. 'INVASION' CITED CITING WHAT SOME MEMBERS CALLED "AN INVASION" OF ILLEGAL IMMIGRANTS ACROSS THE SOUTHERN U.S. BORDER, THE HOUSE OF REPRESENTATIVES VOTED 252-171 ON THURSDAY TO PERMIT THE PENTAGON TO ASSIGN FORCES TO HELP IN BORDER PROTECTIONS. GORDON NOTED THAT WHILE THE U.S. CUSTOMS AND BORDER PROTECTION AGENCY, UNDER THE DEPARTMENT OF HOMELAND SECURITY, IS RESPONSIBLE FOR SECURING THE U.S. BORDERS WITH MEXICO AND CANADA, THE U.S. MILITARY PERFORMS A LIMITED SUPPORT ROLE. FOR EXAMPLE, MILITARY UNMANNED AERIAL VEHICLES HAVE PROVIDED BORDER SURVEILLANCE. HE SAID ANY FURTHER MILITARY ROLE WOULD BE TEMPORARY UNTIL MORE CIVILIAN BORDER AGENTS COULD BE RECRUITED AND TRAINED. GORDON NOTED THAT BORDER SECURITY IS A CIVILIAN LAW ENFORCEMENT FUNCTION. THE POSSE COMITATUS ACT OF 1878, ENACTED DURING THE POST-CIVIL WAR RECONSTRUCTION PERIOD, PROHIBITS FEDERAL MILITARY PERSONNEL FROM ACTING IN A LAW ENFORCEMENT CAPACITY WITHIN THE UNITED STATES. HOWEVER, NATIONAL GUARD TROOPS COME UNDER THE COMMAND OF STATE GOVERNORS, WHO CAN DEPLOY THEM FOR PURPOSES SUCH AS BORDER SECURITY. THE PRESIDENT ALSO HAS THE POWER TO FEDERALIZE THESE TROOPS.