The Chief of Staff of the Air Force (acronym: CSAF, or AF/CC) is a statutory office held by a four-star general in the United States Air Force, and is the most senior uniformed officer assigned to serve in the Department of the Air Force, and as such is the principal military advisor and a deputy to the Secretary of the Air Force; and is in a separate capacity a member of the Joint Chiefs of Staff, and thereby a military adviser to the National Security Council, the Secretary of Defense, and the President. The Chief of Staff is typically the highest-ranking officer on active-duty in the U.S. Air Force unless the Chairman and/or the Vice Chairman of the Joint Chiefs of Staff are Air Force officers.