Which branch of the chain of C2 runs from the SecDef to the Secretaries of the Military Departments?

The administrative branch of the chain of command refers specifically to the supervisory and support functions within the Department of Defense, including oversight of Personnel, Logistics, and other support functions necessary for military operations. By definition, the administrative chain focuses on the relationship and flow of authority from the Secretary of Defense (SecDef) to the Secretaries of the Military Departments, which includes the Army, Navy, and Air Force.

This structure is crucial as it ensures that military departments operate effectively under the direction of the Secretary of Defense while maintaining distinct lines of administration and support. Understanding this hierarchy is essential for grasping how decisions are made and how resources are allocated across the military services. The operational, executive, and coordination branches serve different roles in the broader military framework, emphasizing the importance of recognizing the unique purpose of the administrative branch in managing the forces under the Secretary of Defense's leadership.