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