10 U.S.C. § 12215: Commissioned officers: reserve grade of adjutants general and assistant adjutants general

(a) The adjutant general or an assistant adjutant general of the Army National Guard of a State may, upon being extended Federal recognition, be appointed as a reserve officer of the Army as of the date on which he is so recognized. (b) The adjutant general or an assistant adjutant general of the Air National Guard of a State may be appointed in the reserve commissioned grade in which Federal recognition in the Air National Guard is extended to him.