Mont. Code Ann. § 44-11-306

In any case or controversy involving performance or interpretation of or liability under a mutual aid agreement entered into between one or more law enforcement agencies of political subdivisions of this state and one or more law enforcement agencies of another state or of the United States, the parties to the agreement are the real parties in interest. This state may maintain an action against any law enforcement agency whose default, failure, performance, or other conduct caused or contributed to any liability incurred by this state.