There should be very little legal controversy in the military's employment to defend the border against an unlawful incursion by foreign nationals. The defense of territory and persons is the primary responsibility of the Department of Defense. Other authorities also relevant specifically, the provisions under federal law as vested under Title 10, Chapter 13 of the U.S. code: That whenever the President considers that unlawful obstructions, combinations, or assemblages, or rebellion against the authority of the United States, make it impracticable to enforce the laws of the United States in any State by the ordinary course of judicial proceedings, he...