Massachusetts Constitution Amendments Art. XLVIII, Init., Pt. V, § 1

If an initiative petition for a law is introduced into the general court, signed in the aggregate by not less than such number of voters as will equal three per cent of the entire vote cast for governor at the preceding biennial state election, a vote shall be taken by yeas and nays in both houses before the first Wednesday of May upon the enactment of such law in the form in which it stands in such petition. If the general court fails to enact such law before the first Wednesday of May, and if such petition is completed by filing with the secretary of the commonwealth, not earlier than the first Wednesday of the following June nor later than the first Wednesday of the following July, a number of signatures of qualified voters equal in number to not less than one half of one per cent of the entire vote cast for governor at the preceding biennial state election, in addition to those signing such initiative petition, which signatures must have been obtained after the first Wednesday of May aforesaid, then the secretary of the commonwealth shall submit such proposed law to the people at the next state election. If it shall be approved by voters equal in number to at least thirty per cent of the total number of ballots cast at such state election and also by a majority of the voters voting on such law, it shall become law, and shall take effect in thirty days after such state election or at such time after such election as may be provided in such law.