For forces not assigned to Combatant Commanders, who follows the Secretary of Defense in the chain of command?

The Secretary of Defense is the principal assistant to the President in all matters relating to the Department of Defense. When considering the chain of command for forces not assigned to Combatant Commanders, the Secretaries of the military departments follow the Secretary of Defense. This structure ensures that the military policies are carried out effectively and that the forces are managed directly under the jurisdiction of their respective service branches.

The Secretaries of the military departments, which include the Army, Navy, and Air Force, are responsible for the training, administration, and readiness of their respective forces. They have the authority to formulate policies and manage resources within their services while reporting directly to the Secretary of Defense. This organizational hierarchy ensures a streamlined command structure, allowing for efficient operation and accountability within the armed forces.

Other options, such as the Secretary of the Air Force, would only pertain specifically to the Air Force and do not represent the wider military chain. The National Security Advisor operates outside the Department of Defense, focusing on overall security strategy, and the Deputy Secretaries assist within the department rather than providing direct command over forces.