The Code of Military Justice applies to all members of the national guard when not in federal service under Title 10, United States Code and to all members of the state defense force when performing militia duty. The code has territorial applicability both within and without the state. The code has applicability at all times, provided that either the member is in a duty status or, if not in a duty status, that there is a connection between the act or omission constituting the offense and the efficient functioning of the military forces; however, this grant of military jurisdiction shall not preclude or limit civilian jurisdiction over an offense, which is limited only by the prohibition of double jeopardy.