Department of Defense

Agency

1. federal executive division responsible for ensuring U.S. national security and supervising U.S. military forces. It includes the Joint Chiefs of Staff, the departments of the Army, Navy, and Air Force, and numerous defense agencies and allied services. The department is based in the Pentagon. All military personnel are subject to the Uniform Code of Military Justice, the armed forces' principal body of criminal law. Each military branch maintains its own legal-services division headed by a judge advocate general as well as its own criminal investigative service.