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United States Department of Defense

Department of Defense
Department overview
Formed August 10, 1949 (1949-08-10)
Preceding Department U.S. Department of War and U.S. Department of the Navy
Type Executive Department
Headquarters The Pentagon, Arlington County, Virginia
United States

718,000 (civilian)
1,418,542 (active duty military)
1,100,000+ (reserve):

3.23 million total [1] (2009)
Annual budget US$ 530.1 billion (2010)[2]
US$ 549.1 billion (2011)[3]
US$ 553.0 billion (est. 2012)
Department executives Chuck Hagel, Secretary of Defense
Robert O. Work, Deputy Secretary
Child agencies U.S. Department of the Army
U.S. Department of the Navy
U.S. Department of the Air Force
Website .gov.Defensewww
The Pentagon, headquarters of the United States Department of Defense

The Department of Defense is an executive branch department of the federal 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,[4] with more than 2.13 million active duty servicemen and women[1] as well as their support staff of civilian workers. Adding to the total is over 1.1 million National Guardsmen and Reservists from the four services[2], bringing the total to just over 3.2 million employees.[3]

The Department of Defense is headed by the Secretary of Defense, a cabinet-level head who reports directly to the President of the United States. Beneath the Department of Defense are three subordinate military departments: the U.S. Department of the Army, the U.S. Department of the Navy, and the U.S. Department of the Air Force. In addition, four national intelligence services are subordinate to the Department of Defense: the Defense Intelligence Agency (DIA), the National Security Agency (NSA), the National Geospatial-Intelligence Agency (NGA), and the National Reconnaissance Office (NRO). Other Defense Agencies including the Defense Advanced Research Projects Agency (DARPA), the Defense Logistics Agency (DLA), the Missile Defense Agency (MDA), Defense Threat Reduction Agency (DTRA), and the Pentagon Force Protection Agency (PFPA), all of which are under the command of the Secretary of Defense. Military operations are managed by nine regional or functional Unified Combatant Commands. The Department of Defense also operates several joint services schools, including the National Defense University (NDU) and the National War College (NWC).


  • History 1
  • Organizational structure 2
    • Office of the Secretary of Defense 2.1
      • Defense Agencies 2.1.1
      • National Intelligence Agencies 2.1.2
    • Joint Chiefs of Staff 2.2
    • Military Departments 2.3
    • Unified Combatant Commands 2.4
  • Budget 3
  • Energy use 4
  • Related legislation 5
  • See also 6
  • Notes 7
  • References 8
  • External links 9


The history of the defense of the United States started with the Continental Congress in 1775. The creation of the United States Army was enacted on June 14, 1775.[5] This coincides with the American holiday Flag Day. The Continental Congress would charter the United States Navy, on October 13, 1775.[6] The United States Marine Corps, while today a subordinate department to the Navy, was enacted by the Continental Congress separately on November 10, 1775.[7]

The Preamble of the United States Constitution gave the authority to federal government, to defend its citizens:

The first Congress was seated on March 4, 1789. This first Congress had a huge agenda, that of creating legislation to build a government for the ages. Legislation to create a military defense force went stagnate. Two separate times, President War Department.[8]

Following the aftermath of World War II, President Harry Truman proposed creation of a unified department of national defense. In a special message to Congress on December 19, 1945, the President cited 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.[9]

President Harry Truman signs the National Security Act Amendment of 1949
On July 26, 1947, Truman signed the National Security Act of 1947, which set up a unified military command known as the "National Military Establishment", as well as creating the Central Intelligence Agency, the National Security Council, National Security Resources Board, United States Air Force (formerly the Army Air Forces) and the Joint Chiefs of Staff. The act placed the National Military Establishment under the control of a single Secretary of Defense.[10][11][12] The National Military Establishment formally began operations on September 18, the day after the Senate confirmed James V. Forrestal as the first Secretary of Defense.[11] The National Military Establishment was renamed the "Department of Defense" on August 10, 1949, in an amendment to the original 1947 law.[13]

Under 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.

Organizational structure

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.

The Department of Defense is composed of the Office of the Secretary of Defense (OSD), the Joint Chiefs of Staff (JCS) and the Joint Staff (JS), Office of the Inspector General (DODIG), the Combatant Commands, the Military Departments (Department of the Army (DA), Department of the Navy (DON) & Department of the Air Force (DAF)), the Defense Agencies and Department of Defense Field Activities, the National Guard Bureau (NGB), and such other offices, agencies, activities, organizations, and commands established or designated by law, or by the President or by the Secretary of Defense.

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.[14][15]

Office of the Secretary of Defense

2008 OSD organizational chart

The Office of the Secretary of Defense (OSD) is the Secretary and Deputy Secretary's (mainly) civilian staff.

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 Department of Defense Field Activities.

Defense Agencies

OSD also supervises the following Defense Agencies:

National Intelligence Agencies

Several defense agencies are members of the United States Intelligence Community. These are national-level intelligence services that operate under the jurisdiction of the Department of Defense but simultaneously fall under the authorities of the Director of National Intelligence. They fulfill the requirements of national policy makers and war planners, serve as Combat Support Agencies, and also assist non-Department of Defense intelligence or law enforcement services such as the Central Intelligence Agency and the Federal Bureau of Investigation.

The military services each have their own intelligence elements which are distinct from but subject to coordination by the national intelligence agencies under the Department of Defense. Department of Defense manages the nation's coordinating authorities and assets in the disciplines of signals intelligence, geospatial intelligence, and measurement and signature intelligence and also builds, launches, and operates the Intelligence Community's satellite assets. Department of Defense also has its own human intelligence service which contributes to the CIA's human intelligence efforts while also focusing on military human intelligence priorities. These agencies are directly overseen by the Undersecretary of Defense for Intelligence.

National Intelligence Agencies under Department of Defense

Joint Chiefs of Staff

Joint Chiefs of Staff/Joint Staff organizational chart.

The Joint Chiefs of Staff (JCS) is a body of senior uniformed leaders in the Department of Defense who advise the Secretary of Defense, the Homeland Security Council, the National Security Council and the President on military matters. The composition of the Joint Chiefs of Staff is defined by statute and consists of the Chairman of the Joint Chiefs of Staff (CJCS), Vice Chairman of the Joint Chiefs of Staff (VCJCS), Senior Enlisted Advisor to the Chairman (SEAC), and the Military Service Chiefs from the Army, Navy, Air Force, Marine Corps and the National Guard, all appointed by the President following Senate confirmation.[16] Each of the individual Military Service Chiefs, outside of their Joint Chiefs of Staff obligations, works directly for the Secretary of the Military Department concerned, i.e. Secretary of the Army, Secretary of the Navy, and the Secretary of the Air Force.[17][18][19][20]

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.[21] 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.[22]

The Joint Staff (JS) is a headquarters staff in the Pentagon, composed of personnel from all the four services, that assists the Chairman and the Vice Chairman in discharging their responsibilities and is managed by the Director of the Joint Staff (DJS) who is a Lieutenant General or Vice Admiral.[23][24]

Military Departments

Military Departments of the Department of Defense

There are three Military Departments within the Department of Defense:

  1. the Department of the Army, which the United States Army is organized within.
  2. the Department of the Navy, which the United States Navy and the United States Marine Corps are organized within.
  3. the Department of the Air Force, which the United States Air Force is organized within.

The Military Departments are each headed by their own Secretary (i.e.,

  • United States Department of Defense Official website
  • Department of Defense in the Federal Register
  • Office of the Under Secretary of Defense (Comptroller) Budget and Financial Management Policy
  • Read Congressional Research Service (CRS) Reports regarding the Department of Defense
  • Entire Collection of Department of Defense Freedom of Information Act (FOIA) Reading Room
  • Budget info
  • Death and Taxes: 2009 A visual guide and infographic of the 2009 United States federal budget including the Department of Defense with data provided by the Comptrollers office.
  • Department of Defense YouTube channel
  • Department of Defense Twitter account
  • Department of Defense IA Policy Chart
  • U.S. Reporting Agency
  • U.S. Reporting Agency Groundsquad Homepage
  • Defense Logistics Agency
  • United States Department of Defense collected news and commentary at The Washington Post

External links

  1. ^ "Department of Defense" (PDF). Retrieved 2010-10-15. 
  2. ^ "Budget of the US Government, FY 2011" (PDF). Retrieved 2010-10-15. 
  3. ^
  4. ^ "Which is the world's biggest employer?". BBC News. March 20, 2012. 
  5. ^ Maass, John R. (June 14, 2012). "June 14th: The Birthday of the U.S. Army". U.S. Army Center of Military History. Retrieved June 19, 2014. 
  6. ^ Naval History and Heritage Command. "Navy Birthday Information - 13 October 1775". Retrieved June 19, 2014. 
  7. ^ "Marine Corps: Timeline". United States Marine Corps. Retrieved June 19, 2014. 
  8. ^ "Congress Officially Created the U.S. Military: September 29, 1789". Library of Congress. Retrieved June 20, 2014. 
  9. ^ Hogan, Michael J. (2000). A cross of iron: Harry S. Truman and the origins of the national security state, 1945-1954. Cambridge University Press. pp. 37–38.  
  10. ^ Polmar, Norman (2005). The Naval Institute guide to the ships and aircraft of the U.S. fleet. Naval Institute Press. p. 17.  
  11. ^ a b Hugh W. Nibley (1944-07-04). "Warfare and the Book of Mormon". Retrieved 2010-10-15. 
  12. ^ Bolton, M. Kent (2008). U.S. national security and foreign policymaking after 9/11: present at the re-creation. Rowman & Littlefield. p. 3.  
  13. ^ Rearden, Steven L. (2001). "Department of Defense". In DeConde, Alexander et al. Encyclopedia of American Foreign Policy, Volume 1. Simon and Schuster.  
  14. ^ "Organizational and Management Planning". Retrieved 2013-06-15. 
  15. ^ Department of Defense Directive 5100.01
  16. ^ [1] 10 USC 151. Joint Chiefs of Staff: composition; functions
  17. ^ 10 U.S.C. §3033
  18. ^ 10 U.S.C. §5033
  19. ^ 10 U.S.C. §5043
  20. ^ 10 U.S.C. §8033
  21. ^ 10 U.S.C. §162(b)
  22. ^ 10 U.S.C §151(b)
  23. ^ 10 U.S.C §155
  24. ^ Polmar, Norman (2005). "Defense organization". The Naval Institute guide to the ships and aircraft of the U.S. fleet. Naval Institute Press.  
  25. ^ 10 U.S.C. § 3013, 10 U.S.C. § 5013 and 10 U.S.C. § 8013
  26. ^ a b c d Polmar, Norman (2005). "Defense Organization". The Naval Institute guide to the ships and aircraft of the U.S. fleet. Naval Institute Press. p. 20.  
  27. ^ Watson, Cynthia A. (2010). Combatant Commands: Origins, Structure, and Engagements. ABC-CLIO. p. 3.  
  28. ^ a b c Whitley, Joe D. et al., ed. (2009). "Unified Combatant Commands and USNORTHCOM". Homeland security: legal and policy issues. American Bar Association.  
  29. ^ Reveron, Derek S. (2007). America's Viceroys: The Military and U.S. Foreign Policy. Macmillan. p. 26.  
  30. ^ "Military Spending: Defence Costs". The Economist. June 8, 2011. 
  31. ^ "The SIPRI Military Expenditure Database".  
  32. ^ "United States Federal Budget for Fiscal Year 2010".  
  33. ^ p.53)"vid."United States Federal Budget for Fiscal Year 2010 (.  
  34. ^ a b p.25)"vid."FY 2010 DoD Agencywide Agency Financial Report (. US Department of Defense. Retrieved 7 January 2011. 
  35. ^ "Financial Improvement and Audit Readiness (FIAR) Plan Status Report".  
  36. ^ Andrews Anthony (2011). Department of Defense Facilities: Energy Conservation Policies and Spending. DIANE Publishing. p. 1.  
  37. ^ a b Colonel Gregory J. Lengyel, USAF, The Brookings Institution, Department of Defense Energy Strategy, August 2007.
  38. ^ Colonel Gregory J. Lengyel, USAF, The Brookings Institution, Department of Defense Energy Strategy, August 2007, [2]
  39. ^ Powering America’s Defense: Energy and the Risks to National Security, CNA Analysis & Solutions, May 2009


  1. ^ soldiers, sailors, marines, airmen
  2. ^ Army, Air Force, Navy and Marine Corps
  3. ^ Totals based upon Fiscal Year 2012 numbers.


See also

Other significant legislation related to the Department of Defense includes:

The organization and functions of the Department of Defense are in Title 10 of the United States Code.

Related legislation

The Department of Defense 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 Department components: 1%).[37] 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 Department of Defense would rank 34th in the world in average daily oil use, coming in just behind Iraq and just ahead of Sweden.[38] 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.[39]

In FY 2006, the Department used almost 30,000 gigawatt hours (GWH) of electricity, at a cost of almost $2.2 billion. The Department'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 Department would rank 58th in the world, using slightly less than Denmark and slightly more than Syria (CIA World Factbook, 2006).[37]

The Department of Defense was the largest single consumer of energy in the United States in 2006.[36]

Energy use

The current allocation for the Department of Defense the highest level of budgetary resources among all Federal agencies, and this amounts to more than one-half of the annual Federal discretionary budget.

In the 2010 United States federal budget, the Department of Defense 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.[33] The subsequent 2010 Department of Defense Financial Report shows the total budgetary resources for fiscal year 2010 were $1.2 trillion.[34] 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.[34] After over a decade of non-compliance, Congress has established a deadline of Fiscal year 2017 for the Department of Defense to achieve audit readiness.[35]

The Department of Defense accounts for the majority of federal discretionary spending. In FY 2010 the Department of Defense 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.[32] 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.

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.[30][31]

Chart showing growth in U.S. Department of Defense spending 2000–2011


The United States currently has nine Combatant Commands, organized either on a geographical basis (known as "Area of Responsibility", AOR) or on a global, functional basis:[29]

During military operations, the chain of command runs from the President to the Secretary of Defense to the combatant commanders of the Combatant Commands.[26]

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.[28] Almost all operational U.S. forces are under the authority of a Unified Command.[26] The Unified Commands are governed by a Unified Command Plan, a frequently updated document (produced by the Department of Defense) which lays out the Command's mission, geographical/functional responsibilities, and force structure.[28]

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.[27][28]

Map of the Department of Defense's geographic commands

Unified Combatant Commands

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 [26]

The Secretaries of the Military Departments, in turn, normally exercises authority over their forces by delegation through their respective Service Chiefs (i.e., Chief of Staff of the Army, Chief of Naval Operations, Commandant of the Marine Corps, and Chief of Staff of the Air Force) over forces not assigned to a Combatant Command.[26]

. Deputy Secretary of Defense and (by SecDef delegation) to the Secretary of Defense The Secretaries of the Military Departments are (by law) subordinate to the [25]

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