The Joint Chiefs of Staff, although outside the operational chain of command, is the senior-most military body in the United States Armed Forces. It is led by the Chairman of the Joint Chiefs of Staff, who is the military head of the armed forces and principle advisor to the president and secretary of defense on military matters. Their deputy is the Vice Chairman of the Joint Chiefs of Staff. Other members include the chief of staff of the Army, commandant of the Marine Corps, chief of naval operations, chief of staff of the Air Force, chief of space operations, and the chief of the National Guard Bureau. The commandant of the Coast Guard is not an official member of the Joint Chiefs, but sometimes attends meetings as the one of the military service chiefs. The Senior Enlisted Advisor to the Chairman is the most senior enlisted member in the United States Armed Forces.