The U.S. Department of Defense (DoD) exists to oversee the U.S. military and to protect U.S. national security. Created in 1949 by an act of Congress, it is headed by the secretary of defense and encompasses the army, navy, and air force. In addition to overseeing all armed services personnel, the DoD employs over 700,000 civilians, making it the largest employer in the United States, and it consumes the largest share of the federal budget of any department. The DoD also possesses extensive intelligence capabilities through the National Security Agency (NSA). Finally, the DoD oversees nine Unified Combatant Commands (UCC). These commands are intended to promote unity of action and reduce interservice rivalry. They cover specific regions, which together encompass the entire globe, and are ...