About the Department of Defense - DoD 101

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DoD 101 Introduction to the Department of Defense

DoD 101: Overview of the Department of Defense

Department of Defense 101 Sections

Our Global Infrastructure

The national security depends on our defense installations and facilities being in the right place, at the right time, with the right qualities and capacities to protect our national resources. Those resources have never been more important as America fights terrorists who plan and carry out attacks on our facilities and our people.

Our military servicemembers and civilians operate in every time zone and in every climate. More than 450,000 employees are overseas, both afloat and ashore.

The Defense Department manages an inventory of installations and facilities to keep Americans safe. The Department’s physical plant is huge by any standard, consisting of more than several hundred thousand individual buildings and structures located at more than 5,000 different locations or sites. When all sites are added together, the Department of Defense utilizes over 30 million acres of land.

These sites range from the very small in size such as unoccupied sites supporting a single navigational aid that sit on less than one-half acre, to the Army's vast White Sands Missile Range in New Mexico with over 3.6 million acres, or the Navy’s large complex of installations at Norfolk, Virginia with more than 78,000 employees.

In Comparison...

In terms of people and operations, we’re busier than just about all of the nation’s largest private sector companies.

The Department of Defense has a budget of four hundred nineteen point three billion dollars and more than three million employees; Wal-Mart has a budget of about two hundred twenty-seven billion dollars and employs about one-point-three million people; Exxon-Mobil has a budget of two hundred billion dollars and employs almost ninety-eight thousand; the GM company budget equals one hundred eighty-one billion dollars, it has a workforce of three-hundred sixty-five thousand people; and Ford has a budget of one-hundred sixty billion dollars, and employs three-hundred fifty-four thousand, four hundred people.

Source: Department of Defense Budget

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We Hire the Best

The Department of Defense mission is accomplished seeking out our nation’s best and brightest. Ninety-five percent of our employees have high school diplomas versus seventy-nine percent of the national work force; five-point-six percent of our troops have masters degrees versus four-point-nine percent of the national work force.

Source: U.S. Census Bureau website. Work Force data is based on the total population fifteen years of age and older.

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We Instill Values

Even with top notch recruits we would not be successful if we didn’t provide leadership, professional development, and technical training throughout their careers; we constantly build and reinforce core values that everyone wearing a uniform must live by: duty, integrity, ethics, honor, courage, and loyalty.  Our core values are leadership, professionalism, and technical know-how.

Who We Work For

The Chief Executive Officer:

Our chief executive officer is the President of the United States.  Along with the Secretary of Defense and the National Security Council, the President determines the security needs of the nation, and then take courses of action to ensure that they are met.  The President, in the constitutional role as commander-in-chief of the armed forces, is the senior military authority in the nation and as such is ultimately responsible for the protection of the United States from all enemies, foreign and domestic.

As part of the Constitution’s system of checks and balances, our budget must be approved by the U.S. Congress, which acts as our board of directors.  We accomplish this by working with various committees of both houses, primarily those dealing with funding, military operations, and intelligence.  Their decisions affect our well being and range from setting civilian pay raises to funding major troop deployments.

The Stockholders:

If the President is our CEO, and the Congress is our Board of Directors, then our stockholders are the American people.

Our stockholders know us pretty well.  Almost everyone has had a family member or friend who either works for us now, or used to.

We exist to protect these citizen stockholders, for without their support we would be out of business.

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How We’re Organized

Directions for military operations emanate from the National Command Authority, a term used to collectively describe the President and the Secretary of Defense.  The President, as commander-in-chief of the armed forces, is the ultimate authority. The Office of the Secretary of Defense carries out the Secretary’s policies by tasking the military departments, the Chairman of the Joint Chiefs of Staff and the unified commands.

  • The military departments train and equip the military forces.
  • The Chairman plans and coordinates military deployments and operations.
  • The unified commands conduct the military operations.

Office of the Secretary of Defense

The Office of the Secretary of Defense helps the Secretary plan, advise, and carry out the nation’s security policies as directed by both the Secretary of Defense and the President.

Four key advisers work with the Secretary of Defense in critical areas of policy, finance, force readiness, and purchasing.

Basically, they manage ideas, money, people, and material.

Source: Top Civilian and Military Leaders


Our coordinator for ideas, formulates national security and defense policy and integrates policies and plans to achieve security objectives.


Our chief financial officer, oversees our budgetary and fiscal matters, conducts program analysis and evaluation, and oversees programs to improve general management.

Force Readiness

Our force readiness director, or “people” person, oversees personnel management; the National Guard and Reserve; health affairs; training; and personnel requirements and management, to include equal opportunity, morale, welfare, and quality of life issues.


The Purchasing Director oversees all matters relating to buying, researching, testing, producing, and moving material goods, advises on the use of new technology, protects the environment, and controls the Department’s use of atomic energy.

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Services Train and Equip

We train and equip the armed forces through our three military departments: the Army, Navy and Air Force.  The Marine Corps, mainly an amphibious force, is part of the Department of the Navy.  The primary job of the military departments is to train and equip their personnel to perform warfighting, peacekeeping and humanitarian/disaster assistance tasks.


The Army defends the land mass of the United States, its territories, commonwealths, and possessions; it operates in more than 50 countries.

U.S. Army Organization


The Navy maintains, trains, and equips combat-ready maritime forces capable of winning wars, deterring aggression, and maintaining freedom of the seas.

The U.S. Navy is America’s forward deployed force and is a major deterrent to aggression around the world. Our aircraft carriers, stationed in hotspots that include the Far East, the Persian Gulf, and the Mediterranean Sea, provide a quick response to crises worldwide.

U.S. Navy Mission

Air Force

The Air Force provides a rapid, flexible, and when necessary, a lethal air and space capability that can deliver forces anywhere in the world in less than forty-eight hours; it routinely participates in peacekeeping, humanitarian, and aeromedical evacuation missions, and actively patrols the skies above Iraq Bosnia. Air Force crews annually fly missions into all but five nations of the world.

U.S. Air Force History

Marine Corps

The U.S. Marine Corps maintains ready expeditionary forces, sea-based and integrated air-ground units for contingency and combat operations, and the means to stabilize or contain international disturbance.

U.S. Marine Corps

Coast Guard

The U.S. Coast Guard provides law and maritime safety enforcement, marine and environmental protection, and military naval support.

Prior to the terrorist attacks of Sept. 11, 2001, the U.S. Coast Guard was part of the Department of Transportation during peacetime and part of the Navy's force in times of war. However, since the attacks, it has become part of the Department of Homeland Security.  The U.S. Coast Guard provides unique, critical maritime support, patrolling our shores, performing emergency rescue operations, containing and cleaning up oil spills, and keeping billions of dollars worth of illegal drugs from flooding American communities.

U.S. Coast Guard

Guard & Reserve

The National Guard and Reserve forces provide wartime military support. They are essential to humanitarian and peacekeeping operations, and are integral to the Homeland Security portion of our mission.

Our National Guard and Reserve forces are taking on new and more important roles, at home and abroad, as we transform our national military strategy.  Their personal ties to local communities are the perfect fit for these emerging missions.

National Guard & Reserve

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Office of the Chairman, JCS

An all-service, or “joint” service office supports the Chairman of the Joint Chiefs of Staff in his capacity as the principal military advisor to the President, the National Security Council, and the Secretary of Defense.

Its “board of directors” consists of the Chairman, his deputy, the Vice Chairman, and the four-star heads of the four military services.

The Chairman plans and coordinates military operations involving U.S. forces and as such is responsible for the operation of the National Military Command Center, commonly referred to as the “war room,” from where all U.S. military operations are directed.  He meets regularly with the four Service chiefs to resolve issues and coordinate joint service activities.

Joint Chiefs of Staff

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Unified Commanders

The unified commanders are the direct link from the military forces to the President and the Secretary of Defense.

  • Five commanders have geographical responsibilities.
  • Four commanders have worldwide responsibilities.

The Secretary of Defense exercises his authority over how the military is trained and equipped through the Service secretaries; but uses a totally different method to exercise his authority to deploy troops and exercise military power.  This latter authority is directed, with the advice of the Chairman of the Joint Chiefs of Staff, to the nine unified commands.

Northern Command

Northern Command oversees the defense of the continental United States, coordinates security and military relationships with Canada and Mexico, and direct military assistance to U.S. civil authorities.
For detailed information about U.S. Northern Command please visit: www.northcom.mil.

European Command

The European Command covers more than 13 million square miles and includes 93 countries and territories, to include Iceland, Greenland, the Azores, more than half of the Atlantic ocean, the Caspian sea, and Russia. This territory extends from the North Cape of Norway, through the waters of the Baltic and Mediterranean seas, most of Europe, and parts of the Middle East to the Cape of Good Hope in South Africa.
For detailed information about U.S. European Command please visit: www.eucom.mil.

Central Command

Central Command oversees the balance of the Mid-East, parts of Africa and west Asia, and part of the Indian Ocean.
For detailed information about U.S. Central Command please visit: www.centcom.mil.

Southern Command

Southern Command guards U.S. interests in the southern hemisphere, including Central America, South America, and the Caribbean.
For detailed information about U.S. Southern Command please visit: www.southcom.mil.

Pacific Command

Pacific Command covers 50 percent of the Earth's surface including Southwest Asia, Australia, and shares with U.S. Northern Command responsibility for Alaska.
For detailed information about U.S. Pacific Command please visit: www.pacom.mil.

Africa Command

Africa Command started operations in October 2007. Its mission entails coordinating the kind of support that will enable African governments and existing regional organizations to have greater capacity to provide security and respond in times of need.
For detailed information about U.S. Africa Command, please visit: www.africom.mil.

Strategic Command

The Strategic and Space Commands merged in 2002 and is now known as the Strategic Command which is responsible for controlling space; deterring attacks on the United States and its allies, launching and operating the satellites systems that support our forces worldwide and should deterrence fail, direcing the use of our strategic forces.
For detailed information about U.S. Strategic Command please visit: www.stratcom.mil.

Special Operations Command

Special Operations Command provides counter-paramilitary, counter-narcotics, guerilla, psychological warfare, civil education, and insurgency capabilities in support of U.S. national and international interests. Special Operations Command is responsible for special military support.
For detailed information about U.S. Special Operations Command please visit: www.socom.mil.

Transportation Command

The Transportation Command provide air, land, and sea transportation for the Department of Defense in times of peace and war. It moves people and property around the world.
For detailed information about U.S. Transportation Command please visit: www.transcom.mil.

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Homeland Security and Homeland Defense

The Department of Defense contributes to homeland security through its military missions overseas, homeland defense, and support to civil authorities. Ongoing military operations abroad have reduced the terrorist threat against the United States.

Homeland defense is the protection of US sovereignty, territory, domestic population, and critical defense infrastructure against external threats and aggression, or other threats as directed by the President. The Department of Defense is responsible for homeland defense.

Homeland Defense includes missions such as domestic air defense, maritime intercept operations, land-based defense of critical infrastructure and assets, and, when directed by the President or the Secretary of Defense, the protection of US and its territory from attack. The Department recognizes that threats planned or inspired by "external" actors may materialize internally. The reference to "external threats" does not limit where or how attacks could be planned and executed. The Department is prepared to conduct homeland defense missions whenever the President, exercising his constitutional authority as Commander in Chief, authorizes military actions.

Defense support of civil authorities, often referred to as civil support, is DoD support, including Federal military forces, the Department's career civilian and contractor personnel, and DoD agency and component assets, for domestic emergencies and for designated law enforcement and other activities. The Department of Defense provides defense support of civil authorities when directed to do so by the President or Secretary of Defense.

Department of Homeland Security

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Our Headquarters — The Pentagon

Headquarters of the Department of Defense, the Pentagon is one of the world's largest office buildings. It is twice the size of the Merchandise Mart in Chicago, and has three times the floor space of the Empire State Building in New York.

Built during the early years of World War II, it is still thought of as one of the most efficient office buildings in the world. Despite 17.5 miles of corridors it takes only seven minutes to walk between any two points in the building.

There are five historic elements of the Pentagon that are cited for special attention:

  • The five outer facades of the Pentagon.
  • The Center Courtyard and surrounding facades.
  • The terrace fronting the Mall Entrance.
  • The terrace fronting the River Entrance.
  • The Pentagon’s distinctive five-sided shape.

On October 5, 1992, the Pentagon had been designated as a National Historical Landmark. This designation also automatically placed the Pentagon in the National Register of Historic Places.

The 63-year-old structure is undergoing a $1 billion, multiyear renovation. The project started in the early 1990s and involves a complete overhaul of the interior of the Defense Department headquarters.

The Pentagon renovation project is divided into five wedges. Wedge 1 was almost complete when a terrorist-hijacked commercial airliner slammed into the Pentagon on Sept. 11, 2001. The plane struck that section, so it had to be rebuilt while construction continued on Wedge 2, which was completed in December 2005. All five Wedges are expected to be complete by December 2010.

Sources: The Pentagon, Facts & Figures

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Our Most Important Resource

It’s not tanks,  planes or ships,    it’s... People

We will never compromise on the quality of our most important resource: the people who have chosen to serve you and serve the nation.

They are your sons and daughters, brothers and sisters, husbands and wives.  People of whom we are very proud.

These are the best of America.

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Our Bottom Line

  • To provide the military forces needed to deter war and to protect the security of the United States.
  • Everything we do supports that primary mission.
  • Nothing less is acceptable to us, or to the American people.
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The Department of Defense

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