United States Department of Defense

Upon the seating of the 1st U.S. Congress on 4 March 1789, legislation to create a military defense force stagnated as they focused on other concerns relevant to setting up the new government. President George Washington went to Congress to remind them of their duty to establish a military twice during this time. Finally, on the last day of the session, 29 September 1789, Congress created the War Department.[14][15] The War Department handled naval affairs until Congress created the Navy Department in 1798. The secretaries of each department reported directly to the president as cabinet-level advisors until 1949, when all military departments became subordinate to the Secretary of Defense.

President Truman signs the National Security Act Amendment of 1949

After the end of World War II, President Harry Truman proposed the creation of a unified department of national defense. In a special message to Congress on 19 December 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.[16]

On 26 July 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.[17][18][19] The National Military Establishment formally began operations on 18 September, the day after the Senate confirmed James V. Forrestal as the first secretary of defense.[18] The National Military Establishment was renamed the "Department of Defense" on 10 August 1949 and absorbed the three cabinet-level military departments, in an amendment to the original 1947 law.[20]

Under the Department of Defense Reorganization Act of 1958 (Pub.L. 85–599), channels of authority within the department were streamlined while still maintaining the ordinary authority of the Military Departments to organize, train, and equip their associated forces. The Act clarified the overall decision-making authority of the secretary of defense with respect to these subordinate Military Departments and more clearly defined the operational chain of command over U.S. military forces (created by the military departments) as running from the president to the secretary of defense and then to the unified combatant commanders. Also provided in this legislation was a centralized research authority, the Advanced Research Projects Agency, eventually known as DARPA. The act was written and promoted by the Eisenhower administration and was signed into law 6 August 1958.

A day before the September 11 attacks of 2001, Secretary of Defense Donald Rumsfeld announced that the department was unable to account for about $2.3 trillion worth of transactions. Reuters reported in 2013 that the Pentagon was the only federal agency that had not released annual audits as required by a 1992 law. According to Reuters, the Pentagon "annually reports to Congress that its books are in such disarray that an audit is impossible".[21] In June 2016, the Office of the Inspector General released a report stating that the army made $6.5 trillion in wrongful adjustments to its accounting entries in 2015.[22]

2008 OSD organizational chart

The Office of the Secretary of Defense (OSD) is the secretary and his/her deputy'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, Department of Defense Field Activities, and specialized Cross Functional Teams.

OSD also supervises the following Defense Agencies:

Several defense agencies are members of the United States Intelligence Community. These are national-level intelligence services that operate under the Department of Defense jurisdiction but simultaneously fall under the authorities of the director of national intelligence. They fulfill the requirements of national policymakers 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 that are distinct from but subject to coordination by national intelligence agencies under the Department of Defense. Department of Defense manages the nation's coordinating authorities and assets in 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 the Department of Defense
• 
  Defense Intelligence Agency
• 
  National Security Agency
• 
  National Geospatial-Intelligence Agency
• 
  National Reconnaissance Office

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), the Military Service chiefs from the Army, Marine Corps, Navy, Air Force, and Space Force, in addition to the chief of National Guard Bureau, all appointed by the president following Senate confirmation.[25] Each of the individual Military Service Chiefs, outside their Joint Chiefs of Staff obligations, works directly for the secretary of the Military Department concerned: the secretary of the Army, secretary of the Navy and secretary of the Air Force.[26][27][28][29]

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.[30] 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.[31]

The Joint Staff (JS) is a headquarters staff at the Pentagon made up of personnel from all four services that assist the chairman and vice chairman in discharging their duties, and managed by the director of the Joint Staff (DJS) who is a lieutenant general or vice admiral.[32][33]

There are three Military Departments within the Department of Defense:

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

The Military Departments are each headed by their own secretary (i.e., Secretary of the Army, Secretary of the Navy and Secretary of the Air Force), appointed by the president, with the advice and consent of the Senate. They have the legal authority under Title 10 of the United States Code to conduct all the affairs of their respective departments within which the military services are organized.[34] The secretaries of the Military Departments are (by law) subordinate to the secretary of defense and (by SecDef delegation) to the deputy secretary of defense.

Secretaries of Military Departments, in turn, normally exercise authority over their forces by delegation through their respective service chiefs (i.e., Chief of Staff of the Army, Commandant of the Marine Corps, Chief of Naval Operations, Chief of Staff of the Air Force, and Chief of Space Operations) over forces not assigned to a Combatant Command.[35]

Secretaries of Military Departments and 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, Military Departments are tasked solely with "the training, provision of equipment, and administration of troops."[35]

• Military Departments of the Department of Defense
• 
  Department of the Army
• 
  Department of the Navy
• 
  Department of the Air Force

• Military Services of the Department of Defense
• 
  U.S. Army
• 
  U.S. Marine Corps
• 
  U.S. Navy
• 
  U.S. Air Force
• 
  U.S. Space Force

Combatant command areas of responsibility

A unified combatant command is a military command composed of personnel/equipment from at least two Military Departments, which has a broad/continuing mission.[36][37]

These Military Departments are responsible for equipping and training troops to fight, while the Unified Combatant Commands are responsible for military forces' actual operational command.[37] Almost all operational U.S. forces are under the authority of a Unified Command.[35] 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.[37]

During military operations, the chain of command runs from the president to the secretary of defense to the combatant commanders of the Combatant Commands.[35]

As of 2019 the United States has eleven Combatant Commands, organized either on a geographical basis (known as "area of responsibility", AOR) or on a global, functional basis:[38]

• U.S. Northern Command (USNORTHCOM)
• U.S. Southern Command (USSOUTHCOM)
• U.S. Central Command (USCENTCOM)
• U.S. European Command (USEUCOM)
• U.S. Indo-Pacific Command (USINDOPACOM)
• U.S. Africa Command (USAFRICOM)
• U.S. Strategic Command (USSTRATCOM)
• U.S. Special Operations Command (USSOCOM)
• U.S. Transportation Command (USTRANSCOM)
• U.S. Cyber Command (USCYBERCOM)
• U.S. Space Command (USSPACECOM)

The FY2019 Budget for the Department of Defense is approximately $686,074,048,000[49] (Including Base + Overseas Contingency Operations + Emergency Funds) in discretionary spending and $8,992,000,000 in mandatory spending totaling $695,066,000,000

Undersecretary of Defense (Comptroller) David L. Norquist said in a hearing regarding the FY 2019 budget: "The overall number you often hear is $716 billion. That is the amount of funding for national defense, the accounting code is 050, and includes more than simply the Department of Defense. It includes, for example, the Department of Energy and others. That large a number, if you back out the $30 billion for non-defense agencies, you get to $686 billion. That is the funding for the Department of Defense, split between $617 billion in base and $69 billion in overseas contingency."

The Department of Defense budget encompasses the majority of the National Defense Budget of approximately $716.0 billion in discretionary spending and $10.8 billion in mandatory spending for a $726.8 billion total. Of the total, $708.1 billion falls under the jurisdiction of the House Committee on Armed Services and Senate Armed Services Committee and is subject to authorization by the annual National Defense Authorization Act (NDAA). The remaining $7.9 billion falls under the jurisdiction of other congressional committees.[50]

The Department of Defense is unique because it is one of the few federal entities where the majority of its funding falls into the discretionary category. The majority of the entire federal budget is mandatory, and much of the discretionary funding in the budget consists of DoD dollars.

* Numbers may not add due to rounding