Wis. Const. art. XII, § 1

Any amendment or amendments to this constitution may be proposed in either house of the legislature, and if the same shall be agreed to by a majority of the members elected to each of the two houses, such proposed amendment or amendments shall be entered on their journals, with the yeas and nays taken thereon, and referred to the legislature to be chosen at the next general election, and shall be published for three months previous to the time of holding such election; and if, in the legislature so next chosen, such proposed amendment or amendments shall be agreed to by a majority of all the members elected to each house, then it shall be the duty of the legislature to submit such proposed amendment or amendments to the people in such manner and at such time as the legislature shall prescribe; and if the people shall approve and ratify such amendment or amendments by a majority of the electors voting thereon, such amendment or amendments shall become part of the constitution; provided, that if more than one amendment be submitted, they shall be submitted in such manner that the people may vote for or against such amendments separately.