Defense Department

Secretary of Defense

Why It Matters

With the largest budget of any single part of the executive branch, the Department of Defense projects U.S. power across the globe, maintains the country's military superiority, and, when necessary, wages war against America's adversaries.

The Defense Department currently has bases in 38 foreign countries. Its land forces circumnavigate the world, its Navy dominates the seas and its air power outflanks that of any other country. In 2009, it had more then 539,000 facilities on more than 28.5 million acres.

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Background

At a Glance

# of Employees: 3 million+
2010 Budget: $530.8 billion (enacted budget authority)
Address: 1400 Defense Pentagon, Washington, DC, 20301-1400
Web site

History

The Department of Defense was birthed during the aftermath of World War II. In 1947, the National Security Act joined the Department of War and the Department of the Navy into a single entity. During the war, the government had constructed a new headquarters for its military department, the Pentagon, which became the home of the new Department of Defense. Under the new organization, the War Department split into the Department of the Army and the Department of the Air Force. The National Security Act also formalized the creation of the Joint Chiefs of Staff, a group of the highest-ranking military officials from each service, who had been meeting throughout the war to coordinate their strategy.

Today, the Armed Forces are divided in two different ways, by service and by command. Three service departments - the Army, the Navy and the Air Force - organize members of the military according to the type of work they do and the arena in which they fight. (The Marine Corps falls under the Department of the Navy). Ten unified combatant commands organize forces from all the services into geographical or functional areas. Forces from the Army, Navy and Air Force all serve in Central Command, which has responsibility for the military's work in Iraq and Afghanistan, for instance.

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Offices

Court of Military Appeals
Defense Acquisition University
Department of the Air Force
Department of the Army
Department of the Navy
National Defense University
Office of the Inspector General
Office of the Secretary of Defense
- Assistant Secretary of Defense for Legislative Affairs
- Assistant Secretary of Defense for Networks and Information Integration
- Assistant Secretary of Defense for Public Affairs
- Defense Advanced Research Projects Agency
- Defense Business Transformation Agency
- Defense Commissary Agency
- Defense Contract Audit Agency
- Defense Contract Management Agency
- Defense Finance and Accounting Service
- Defense Information Systems Agency
- Defense Intelligence Agency
- Defense Legal Services Agency
- Defense Logistics Agency
- Defense Media Activity
- Defense Prisoner of War-Missing Personnel Office
- Defense Security Cooperation Agency
- Defense Security Service
- Defense Technical Information Center
- Defense Technology Security Administration
- Defense Threat Reduction Agency
- Director of Administration and Management
- Director of Net Assessment
- Director of Operational Test and Evaluation
- DoD Education Activity
- DoD Human Resources Activity
- DoD Test Resource Management Center
- Missile Defense Agency
- National Geospatial-Intelligence Agency
- National Reconnaissance Office
- National Security Agency-Central Security Service
- Office of Economic Adjustment
- Office of the Director of Cost Assessment and Program Evaluation
- Office of the General Counsel
- Pentagon Force Protection Agency
- TRICARE Management Activity
- Under Secretary of Defense (Comptroller)
- Under Secretary of Defense for Acquisition, Technology and Logistics
- Under Secretary of Defense for Intelligence
- Under Secretary of Defense for Personnel and Readiness
- Under Secretary of Defense for Policy
- Washington Headquarters Services
The Organization of the Joint Chiefs of Staff
U.S. Africa Command
U.S. Central Command
U.S. European Command
U.S. Joint Forces Command
U.S. Northern Command
U.S. Pacific Command
U.S. Southern Command
U.S. Special Operations Command
U.S. Strategic Command
U.S. Transportation Command