Any citizen of the United States 18 years of age or older who meets the registration and residence requirements provided by law is a qualified elector unless he is serving a sentence for a felony in a penal institution or is of unsound mind, as determined by a court.
Qualified elector
Mont. Const. art. IV, § 2, under SUFFRAGE AND ELECTIONS.
Mont. Const. art. IV, § 2
Qualified elector