D.C. Code § 49-101

Any drill, parade, encampment or duty that is required, ordered, or authorized to be performed under the provisions of this title, shall be deemed to be a military duty, and while on such duty every officer and enlisted man of the National Guard shall be subject to the lawful orders of his superior officers, and for any military offense may be put and kept under arrest or under guard for a time not extending beyond the term of service for which he is then ordered.