United States Department of Defense - Command Structure

The command structure of the Department of Defense is defined by the Goldwater-Nichols Act of 1986. Under the act, the chain of command runs from the President of the United States, through the Secretary of Defense, to the combatant commanders (COCOM) who command all military forces within their area of responsibility. The Chairman of the Joint Chiefs of Staff and the service Chiefs of Staff are responsible for readiness of the U.S. military and serve as the President's military advisers, but are not in the chain of command. The Chairman of the Joint Chiefs of Staff is by law the highest ranking military officer in the United States.