Mont. Code Ann. § 10-1-701

The home guard may be organized, maintained, and disbanded at the discretion of the governor, in accordance with federal law and regulation, when additional defense forces are needed in this state. The home guard shall be composed of officers assigned to it and any able-bodied citizen of this state who volunteers to serve in it. If additional persons are needed in the home guard, members of the unorganized militia shall serve if enrolled by draft or otherwise as provided by law and regulation.