During an initial mobilization, the organization of a unit of the Army National Guard of the United States or of the Air National Guard of the United States ordered into active Federal service shall, so far as practicable, be maintained as it existed on the date of the order to duty.
Structure US Code
Subtitle E— Reserve Components
CHAPTER 1211— NATIONAL GUARD MEMBERS IN FEDERAL SERVICE
§ 12401. Army and Air National Guard of the United States: status
§ 12404. Army and Air National Guard of the United States: mobilization; maintenance of organization
§ 12405. National Guard in Federal service: status
§ 12406. National Guard in Federal service: call
§ 12407. National Guard in Federal service: period of service; apportionment
§ 12408. National Guard in Federal service: physical examination