General

The Department of Defense (DOD) is the executive branch of the United States government created by Congress in 1949. The DOD directs and controls the armed forces and assists the President in the direction of the nation’s security.

The major subdivisions of the DOD are three military departments, the Office of the Secretary of Defense (OSD), the Joint Chiefs of Staff (JCS), defense agencies, and DOD field activities. The staff of the DOD is primarily civilian. It advises and assists the Secretary in top-level management. Also at this level, the military, economic, and political elements associated with military preparedness are balanced to determine size and structure of the armed forces.

The military departments are responsible for recruiting, training and equipping their forces, but operational control of those forces is assigned to one of the Unified Combatant Commands.

Office of the Secretary of Defense (OSD)

To assist the SECDEF in carrying out his multiple responsibilities, the Secretary has a Deputy Secretary, four Under Secretaries of Defense (USD), nine Assistant Secretaries of Defense (ASD), three Assistants to the Secretaries of Defense (ATSD), nine Deputy Under Secretaries (DUSD), three Principal Deputy Under Secretaries (PDUSD), the General Counsel (GC), the Inspector General (IG) and five Directors. Collectively, this group and their staffs are referred to as the Office of the Secretary of Defense (OSD). OSD is comprised of about 2000 people, 1500 of whom are civilians and 500 of whom are military personnel.

The Deputy Secretary of Defense is the alter ego of the Secretary. He is responsible for coordination and supervision of the Department as directed by the Secretary. Normally the SECDEF delegates a great deal of his authority to the Deputy. The number two man can issue directives to all the subunits of governmental agencies, and to international bodies in the name of the Secretary.