National Command Authority

The term National Command Authority (or NCA) is used in United States military and government circles to refer to the ultimate lawful source of military orders. The term refers to the President of the United States and the Secretary of Defense.

Only the NCA can order the use of nuclear weapons, including the Single Integrated Operational Plan (SIOP). Neither individual, by himself, can order that strategic nuclear weapons be used against any country or region.

If the NCA determines that a nuclear strike is necessary, they must jointly inform the Chairman of the Joint Chiefs of Staff, who in turn will direct a general officer on duty in the National Military Command Center (NMCC) at the Pentagon to execute the SIOP.

The use of the term dates from the Cold War era in which the United States and Soviet Union had nuclear missiles on constant alert and a responsible official had to be available to authorize a retaliatory strike within a matter of minutes. Detailed Continuity of Government plans provided for monitoring the whereabouts of certain key government officials who would become the National Command Authority if the President were himself victim of an enemy attack.

It must be noted that as a matter of constitutional law, the President represents the unitary executive power of the United States. Therefore, if the Secretary of Defense refuses any order of the President, the President is free to dismiss him, in which case authority devolves to a subordinate (see Saturday Night Massacre, in the context of the Justice Department). Presumably, the President is legally free to continue to fire subordinates until such time as he reaches an acting Secretary of Defense who agrees with his judgment (see Robert Bork, again in the Justice Department context).