D.C. Code § 49-304

The President may assign an officer of the Army to act as Adjutant General of the militia of the District of Columbia, who, while so assigned, shall be commissioned as such and be subject to the orders of the Commanding General and the provisions of this title; provided, however, that the officer so assigned shall receive no other pay or emolument than that to which his rank in the Army entitles him when on detached service.