Who comprises the National Command Authority (NCA)?

• A. Composed of the Secretary of Defense alone.
• B. The President and the Secretary of Defense (and designated alternates).
• C. The Joint Chiefs of Staff and the President.
• D. The Secretary of Defense and the Chair of the Joint Chiefs.

Answer: (B)

The key idea here is who has the final authority to order the use of nuclear weapons. The National Command Authority is composed of two civilian leaders who share this ultimate responsibility, with designated alternates to ensure continuity if one or both cannot perform their duties. That pairing is the President and the Secretary of Defense, plus those designated alternates who can act in their absence. This structure safeguards civilian control of the most grave military decision and guarantees there’s always a valid authority to act in a crisis. It isn’t the Joint Chiefs of Staff, nor is it the Secretary of Defense alone, or the Secretary of Defense paired with the Chair of the Joint Chiefs, since the Chair participates in planning and advising but does not constitute the nucleus of the NCA.