Our chapter on foreign policy and national security discusses the role of the secretary of defense. Robert Gates, who held that posts under Presidents Bush and Obama, discusses it in his memoirs (p. 82):
In truth, nothing can prepare you for being secretary of defense, especially during wartime. The size of the place and its budget dwarf everything else in government. As I quickly learned from 535 members of Congress, its programs and spending reach deeply into every state and nearly every community. Vast industries and many local economies are dependent on decisions made in the Pentagon every day. The secretary of defense is second only to the president in the military chain of command (neither the vice president nor the chairman of the Joint Chiefs of Staff is in the chain at all), and any order to American forces worldwide goes from the president to the secretary directly to the combatant commanders (although as a practical matter and a courtesy, I routinely asked the chairman to convey such orders). More important than any of the meetings, the secretary makes life-and-death decisions every day—and not just for American military forces. Since 9/11, the president has delegated to the secretary the authority to shoot down any commercial airliner he, the secretary, deems to be a threat to the United States. The secretary can also order missiles fired to shoot down an incoming missile. He can move bombers and aircraft carriers and troops. And every week he makes the decisions on which units will deploy to the war front and around the world. It is an unimaginably powerful position.
The Department of Defense (DOD) was established after World War II through the 1947 National Security Act (P.L. 80-253). At the time, some, including President Truman, took the view that the different components of the U.S. military had been insufficiently integrated to wage World War II effectively. The intention of the 1947 Act was therefore to create, for the first time, an integrated institution that combined the Departments of War and Navy, and to establish a policy architecture for overseeing the newly reorganized military apparatus. Over time, DOD has grown into one of the largest bureaucracies in the world, currently comprising more than 2.9 million servicemembers and civilians stationed in 4,686 sites across the United States and around the globe. Congress, in its constitutional role, legislates both defense authorization and appropriations bills, and conducts oversight on DOD. The Senate confirms multiple military officers and certain DOD civilian officials.
