Miss. Code Ann. § 33-7-7

The commander in chief is authorized to order out the Mississippi National Guard, or any part thereof, for training or service beyond the borders of the state, with any part of the Armed Forces of the United States, whenever participation in such training or serving is authorized by the secretary of defense, or to repel invasion. Whenever the Mississippi National Guard, or any part thereof, not being in the service of the United States, goes beyond the limits of the state, they shall still remain under the military laws and regulations of the state, and any military court of the state shall have jurisdiction over any offense against the military laws of the state committed by any member of the Mississippi National Guard while performing any such military duty beyond the limits of the state, whether such court be organized and sit in the state or not.