The Joint Chiefs of Staff (JCS) is a group of senior military leaders in the United States. It includes the heads of each branch of the military: the Army, Navy, Air Force, Marine Corps, and the Chief of the National Guard Bureau. The JCS advises the President and the Secretary of Defense on military matters and strategy. The JCS is led by the Chairman of the Joint Chiefs of Staff, who is the highest-ranking military officer. This organization plays a crucial role in coordinating military operations and ensuring that the different branches work together effectively during conflicts and peacekeeping missions.