If the militia of the State is ordered under the Constitution and laws of the United States into the active military service of the United States, the Governor may order out for active duty the organized militia. If the number of organized militia available is insufficient, the Governor may order out the unorganized militia. Each member of the unorganized militia who volunteers or is ordered out is subject to court-martial under this title for failure to appear at the time and place designated by the member’s commanding officer.