Montana Constitution, Article XIV
Section 8. Amendment by legislative referendum. Amendments to this constitution may be proposed by any member of the legislature. If adopted by an affirmative roll call vote of two-thirds of all the members thereof, whether one or more bodies, the proposed amendment shall be submitted to the qualified electors at the next general election. If approved by a majority of the electors voting thereon, the amendment shall become a part of this constitution on the first day of July after certification of the election returns unless the amendment provides otherwise. 