National Command Authority
National Command Authority (NCA) is a term used by the Department of Defense of the United States of America to refer to the ultimate source of lawful military orders. The NCA comprises the President of the United States (as commander-in-chief) and the Secretary of Defense jointly, or their duly deputized successors, i.e. the Vice President and the Deputy Secretary of Defense. The term also refers to communications with the commanding officers of the Unified Combatant Commands to put U.S. forces into action.
The NCA consists only of the President and the Secretary of Defense or their duly deputized alternates or successors. The chain of command runs from the President to the Secretary of Defense (SecDef) and through the Joint Chiefs of Staff to the Commanders of the Unified and Specified Commands. The channel of communication for execution of the Single Integrated Operational Plan (SIOP) and other time-sensitive operations shall be from the NCA through the Chairman of the Joint Chiefs of Staff, representing the Joint Chiefs of Staff, to the executing commanders.— Section 3.1, Department of Defense Directive Number 5100.30 December 2, 1971
Authorization of a nuclear or strategic attack
Only the President can direct the use of nuclear weapons, including the Single Integrated Operational Plan (SIOP). While the President does have unilateral authority as commander-in-chief to order that nuclear weapons be used for any reason at any time, the actual procedures and technical systems in place for authorizing the execution of a launch order requires a secondary confirmation under a two-man rule, as the President's order is subject to secondary confirmation by the Secretary of Defense. If the Secretary of Defense does not concur, then the President may in his sole discretion fire the Secretary. The Secretary of Defense has legal authority to approve the order, but cannot veto it.
- "World-Wide Military Command and Control System (WWMCCS), Department of Defense Directive 5100.30". Issued by Deputy Secretary of Defense David Packard on December 2, 1971.
- Beauchamp, Zack (August 3, 2016). "If President Trump Decided to Use Nukes, He Could Do It Easily". Vox. Retrieved October 2, 2016.
- Blair, Bruce (June 11, 2016). "What Exactly Would It Mean to Have Trump's Finger on the Nuclear Button?". Politico Magazine. Retrieved October 2, 2016.
- Broad, William J.; Sanger, David E. (August 4, 2016). "Debate Over Trump's Fitness Raises Issue of Checks on Nuclear Power". The New York Times. p. A1. Retrieved October 2, 2016.