Department of Defense

Department of Defense — Foundation and Numbers

DoD Size

The Department of Defense is America's LARGEST government agency:

Over 1.3 million members in the Regular Forces
826,000 in the National Guard and Reserve Forces
742,000 civilian personnel

DoD Mission

The mission of the Department of Defense is to:

Provide military forces to deter war
Protect the security of our country

DoD Organization

DoD HQ

Headquartered at the Pentagon, the Department of Defense includes:

Office of the Secretary of Defense
Joint Chiefs of Staff
Joint Staff
Departments of the Army, Navy (including the Marine Corps), and Air Force (including the Space Force)

Additional DoD Components

Furthermore, the Department of Defense includes:

Unified combatant commands (CCMD)
Forces dedicated to combined commands
Defense agencies
Field activities

SecDef Reports to President

SecDef Reports

As the civilian head of the Department of Defense, the Secretary of Defense reports directly to the U.S. President.

Department of Defense — SecDef, Armed Forces Policy Council, Under Secretaries

Secretary of Defense (SecDef)

SecDef Appointment

The Secretary of Defense (SecDef) is appointed by the U.S. President, with advice and consent of the Senate.

SecDef Role

The SecDef serves as:

Principal defense policy advisor to the U.S. President
Responsible for the formulation of general defense policy
Responsible for policy related to all matters of direct and primary concern to the Department of Defense
Responsible for the execution of approved policy

SecDef Specific Responsibility

SecDef Specific

In addition to exercising the operational chain of command between the U.S. President and the CCDRs, a specific responsibility of the SecDef is to provide written policy guidance for:

Department of Defense national security objectives and policies
Military mission priorities
Projected levels for available resources

SecDef Contingency Guidance

SecDef Contingency

The SecDef also provides the Chairman of the Joint Chiefs of Staff with written policy guidance regarding contingency plans.

Threat Detection Guidance

The Secretaries of the military departments and the CCDRs are provided written guidelines to direct the effective detection and monitoring of all potential aerial and maritime threats to the national security of the United States.

Armed Forces Policy Council

Armed Forces Policy Council Function

The Armed Forces Policy Council:

Assists in matters requiring a long-range view
Formulates broad defense policy
Advises the Secretary of Defense on policies, as requested

Council Membership

The Armed Forces Policy Council consists of:

Secretary of Defense (serving as the Chairman of the Council)
Deputy Secretary of Defense
Secretaries of the Army, Navy, and USAF
Chairman of the Joint Chiefs of Staff
Under Secretary of Defense for Acquisition and Sustainment
Under Secretary of Defense for Research and Engineering
Under Secretary of Defense for Policy
Deputy Under Secretary of Defense for Acquisition and Technology
Deputy Under Secretary of Defense for Research and Engineering
Deputy Under Secretary of Defense for Acquisition and Sustainment
Service Chiefs

Under Secretaries of Defense

6 Under Secretaries

There are SIX Under Secretaries of Defense who assist the Secretary of Defense:

Policy
Comptroller
Personnel and Readiness
Acquisition and Sustainment (A&S)
Research and Engineering
Intelligence

Special Agencies

The Secretary of Defense receives staff assistance through a number of special agencies, such as:

Defense Threat Reduction Agency
Security Service
Defense Logistics Agency

…which provide special skills, expertise, and advice.