The chief is either an Army or an Air Force four-star general officer, and is the senior uniformed National Guard officer, and is a member of the Joint Chiefs of Staff. In this capacity, he serves as a military adviser to the President, the Secretary of Defense, the National Security Council and is the Department of Defense's official channel of communication to the Governors and to State Adjutants General on all matters pertaining to the National Guard. He is responsible for ensuring that the more than half a million Army and Air National Guard personnel are accessible, capable, and ready to protect the homeland and to provide combat resources to the Army and the Air Force.