The Pentagon, headquarters of the United States Department of Defense.
The Department of Defense (Defense Department, USDOD, DOD, DoD or the Pentagon) is the executive department of the government of the United States charged with coordinating and supervising all agencies and functions of the government concerned directly with national security and the United States Armed Forces. The Department is also the largest employer in the world, with more than 2.13 million active duty soldiers, sailors, marines, airmen, and civilian workers, and over 1.1 million National Guardsmen and members of the Army, Navy, Air Force, and Marine Reserves. The grand total is just over 3.2 million servicemen, servicewomen, and civilians.
In a special message to Congress on December 19, 1945, President Harry Truman proposed creation of a unified department of state defense, citing both wasteful military spending and inter-departmental conflicts. Deliberations in Congress went on for months focusing heavily on the role of the military in society and the threat of granting too much military power to the executive.
Under the Department of Defense Reorganization Act of 1958 (Pub.L. 85–899), channels of authority within the department were streamlined, while still maintaining the authority of the Military Departments. Also provided in this legislation was a centralized research authority, the Advanced Research Projects Agency, eventually known as DARPA. The Act moved decision-making authority from the Military Departments to the Joint Chiefs of Staff and the Secretary of Defense. It also strengthened the command channel of the military over U.S. forces from the President to the Secretary of Defense. Written and promoted by the Eisenhower administration, it was signed into law August 6, 1958.
Department of Defense organizational chart (March 2012)
The Secretary of Defense, appointed by the President with the advice and consent of the Senate, is by federal law (10 U.S.C. § 113) the head of the Department of Defense, "the principal assistant to the President in all matters relating to Department of Defense", and has "authority, direction and control over the Department of Defense". Because the Constitution vests all military authority in Congress and the President, the statutory authority of the Secretary of Defense is derived from their constitutional authorities. Since it is impractical for either Congress or the President to participate in every piece of Department of Defense affairs, the Secretary of Defense, and the Secretary's subordinate officials generally exercise military authority.
Department of Defense Directive 5100.01 describes the organizational relationships within the Department, and is the foundational issuance for delineating the major functions of the Department. The latest version, signed by former Secretary of Defense Robert Gates in December 2010, is the first major re-write since 1987.
OSD is the principal staff element of the Secretary of Defense in the exercise of policy development, planning, resource management, fiscal and program evaluation and oversight, and interface and exchange with other U.S. Government departments and agencies, foreign governments, and international organizations, through formal and informal processes. OSD also performs oversight and management of the Defense Agencies and DoD Field Activities.
OSD also supervises the following Defense Agencies:
Following the Goldwater-Nichols Act in 1986 the Joint Chiefs of Staff do not have operational command authority, neither individually nor collectively, as the chain of command goes from the President to the Secretary of Defense, and from the Secretary of Defense to the Commanders of the Combatant Commands. Goldwater-Nichols also created the office of Vice Chairman, and the Chairman is now designated as the principal military adviser to the Secretary of Defense, the Homeland Security Council, the National Security Council and to the President.
The Secretaries of the Military Departments and the Service Chiefs do not possess operational command authority over U.S. troops (this power was stripped from them in the Defense Reorganization Act of 1958), and instead the Military Departments are tasked solely with "the training, provision of equipment, and administration of troops."
Unified Combatant Commands
Map of the DoD's geographic commands
A Unified Combatant Command is a military command composed of personnel and equipment from at least two Military Departments, which has a broad and continuing mission.
The Military Departments are responsible for equipping and training the troops to fight, while the Unified Combatant Commands are responsible for actual operational command of military forces. Almost all operational U.S. forces are under the authority of a Unified Command. The Unified Commands are governed by a Unified Command Plan, a frequently updated document (produced by the DOD) which lays out the Command's mission, geographical/functional responsibilities, and force structure.
Department of Defense spending in 2010 was 4.8% of GDP and accounted for approximately 45% of budgeted global military spending – more than the next 17 largest militaries combined.
The Department of Defense accounts for the majority of federal discretionary spending. In FY 2010 the DOD budgeted spending accounted for 21% of the U.S. Federal Budget, and 53% of federal discretionary spending, which represents funds not accounted for by pre-existing obligations. However, this does not include many military-related items that are outside of the Defense Department budget, such as nuclear weapons research, maintenance, cleanup, and production, which is in the Department of Energy budget, Veterans Affairs, the Treasury Department's payments in pensions to military retirees and widows and their families, interest on debt incurred in past wars, or State Department financing of foreign arms sales and militarily-related development assistance. Neither does it include defense spending that is not military in nature, such as the Department of Homeland Security, counter-terrorism spending by the FBI, and intelligence-gathering spending by NASA.
In the 2010 United States federal budget, the DoD was allocated a base budget of $533.7 billion, with a further $75.5 billion adjustment in respect of 2009, and $130 billion for overseas contingencies. The subsequent 2010 DoD Financial Report shows DoD total budgetary resources for fiscal year 2010 were $1.2 trillion. Of these resources, $1.1 trillion were obligated and $994 billion were disbursed, with the remaining resources relating to multi-year modernization projects requiring additional time to procure. After over a decade of non-compliance, Congress has established a deadline of FY 2017 for the DoD to achieve audit readiness.
The Department of Defense was the largest single consumer of energy in the United States in 2006.
In FY 2006, the Department used almost 30,000 gigawatt hours (GWH) of electricity, at a cost of almost $2.2 billion. The DoD's electricity use would supply enough electricity to power more than 2.6 million average American homes. In electricity consumption, if it were a country, the DoD would rank 58th in the world, using slightly less than Denmark and slightly more than Syria (CIA World Factbook, 2006).
The DOD is responsible for 93% of all US government fuel consumption in 2007 (Department of the Air Force: 52%; Department of the Navy: 33%; Department of the Army: 7%; other DoD components: 1%). The Department of Defense uses 4,600,000,000 US gallons (1.7×1010 L) of fuel annually, an average of 12,600,000 US gallons (48,000,000 L) of fuel per day. A large Army division may use about 6,000 US gallons (23,000 L) per day. According to the 2005 CIA World Factbook, if it were a country, the DoD would rank 34th in the world in average daily oil use, coming in just behind Iraq and just ahead of Sweden. The Air Force is the largest user of fuel energy in the federal government. The Air Force uses 10% of the nation's aviation fuel. (JP-8 accounts for nearly 90% of its fuels.) This fuel usage breaks down as such: 82% jet fuel, 16% facility management and 2% ground vehicle/equipment.