Mich. Comp. Laws § 9
The people reserve to themselves the power to propose laws and to enact and reject laws, called the initiative, and the power to approve or reject laws enacted by the legislature, called the referendum. The power of initiative extends only to laws which the legislature may enact under this constitution. The power of referendum does not extend to acts making appropriations for state institutions or to meet deficiencies in state funds and must be invoked in the manner prescribed by law within 90 days following the final adjournment of the legislative session at which the law was enacted. To invoke the initiative or referendum, petitions signed by a number of registered electors, not less than eight percent for initiative and five percent for referendum of the total vote cast for all candidates for governor at the last preceding general election at which a governor was elected shall be required. No law as to which the power of referendum properly has been invoked shall be effective thereafter unless approved by a majority of the electors voting thereon at the next general election. Any law proposed by initiative petition shall be either enacted or rejected by the legislature without change or amendment within 40 session days from the time such petition is received by the legislature. If any law proposed by such petition shall be enacted by the legislature it shall be subject to referendum, as hereinafter provided. If the law so proposed is not enacted by the legislature within the 40 days, the state officer authorized by law shall submit such proposed law to the people for approval or rejection at the next general election. The legislature may reject any measure so proposed by initiative petition and propose a different measure upon the same subject by a yea and nay vote upon separate roll calls, and in such event both measures shall be submitted by such state officer to the electors for approval or rejection at the next general election.
Any law submitted to the people by either initiative or referendum petition and approved by a majority of the votes cast thereon at any election shall take effect 10 days after the date of the official declaration of the vote. No law initiated or adopted by the people shall be subject to the veto power of the governor, and no law adopted by the people at the polls under the initiative provisions of this section shall be amended or repealed, except by a vote of the electors unless otherwise provided in the initiative measure or by three-fourths of the members elected to and serving in each house of the legislature. Laws approved by the people under the referendum provision of this section may be amended by the legislature at any subsequent session thereof. If two or more measures approved by the electors at the same election conflict, that receiving the highest affirmative vote shall prevail. The legislature shall implement the provisions of this section.
MCL 9