The National Command Authority (NCA) is a term that was formerly used by the
Department of Defense of the
United States to refer to the ultimate source of lawful military orders.
The NCA was first alluded to in a 1960 Department of Defense document. It included at least the
President of the United States as
commander-in-chief and the
Secretary of Defense. The term has no statutory or constitutional basis and was replaced in 2002 in favor of explicitly referring to the President and/or the Secretary of Defense.[1][2]
Only the President can direct the use of
nuclear weapons by U.S. Armed Forces, through plans like
OPLAN 8010-12. The President has unilateral authority as commander-in-chief to order that nuclear weapons be used for any reason at any time.[3][4][5][6]