When the militia of the state is called into federal service under the Constitution and laws of the United States, the Governor shall order out for service the organized militia or such part thereof as may be necessary; and, if the number available is insufficient, the Governor may call for and accept from the unorganized militia as many volunteers as are required for service in the organized militia. During the absence of the organized militia in the service of the United States, their state designations shall not be given to new organizations.
OCGA § 38-2-5