The U.S. Secretaries of Defense are the leaders of the U.S. Department of Defense, responsible for overseeing the nation's military and ensuring national security. They advise the President of the United States on defense matters and manage the armed forces, including the Army, Navy, and Air Force. Appointed by the President and confirmed by the Senate, Secretaries of Defense play a crucial role in shaping military policy and strategy. They also work with international allies and address issues such as military readiness, defense budgets, and global security challenges.