Mont. Code § 13-36-207
The petitioner (contestant) and the contestee may appear and produce evidence at the hearing, but no person other than the petitioner and contestee may be made a party to the proceedings on the petition and no person other than the parties and their attorneys may be heard except by order of the court. If more than one petition is pending or the election of more than one person is contested, the court may in its discretion order the cases to be heard together and may apportion the costs, disbursements, and attorney fees between the parties and shall finally determine all questions of law and fact, except that the judge may impanel a jury to decide on questions of fact. In the case of nominations or elections other than for federal congressional offices, the court shall immediately certify its decision to the governing body or official issuing certificates of nomination or election and the governing body or official shall issue certificates of nomination or election to the person or persons entitled to the certificates by the court's decision. If judgment of ouster against a defendant is rendered, the nomination or office must be declared vacant by the judgment, except as provided in 13-36-212, and must be filled by a new election or by appointment as may be provided by law regarding vacancies in the nomination or office.
§ 13-36-207, MCA