There are three ways to amend the Michigan Constitution: a proposal passed by two-thirds of each chamber of the state legislature, a citizen-initiated petition that gathers enough signatures to reach the ballot, or a full constitutional convention. All three paths end the same way. A majority of voters casting ballots on the question at a general election must approve the change before it becomes part of the constitution.
Amendment by the Legislature
The legislative route is set out in Article XII, Section 1. A proposed amendment can be introduced in either the House or the Senate, and it advances only if two-thirds of the members elected to and serving in each chamber vote yes.1Michigan Legislature. Michigan Constitution Article XII Section 1
If both chambers clear that threshold, the proposal goes straight to voters at the next general election. The governor plays no role. There is no signature, no veto. Because neither party typically holds a supermajority in Lansing, most legislative amendment attempts stall well before reaching the ballot.
Amendment by Citizen Petition
Michigan residents can put an amendment on the ballot without going through the legislature at all. Article XII, Section 2 sets the signature requirement at 10% of the total votes cast for all candidates for governor in the most recent gubernatorial election.2Michigan Legislature. Michigan Constitution Article XII Section 2 After the 2022 gubernatorial election, that number sits at roughly 446,198 valid signatures.
Two deadlines control the calendar. All signatures must be collected within 180 days, and the completed petition must be filed with the Secretary of State at least 120 days before the election at which voters would decide the question.2Michigan Legislature. Michigan Constitution Article XII Section 2 The petition itself must include the full text of the proposed amendment. Drives that begin gathering signatures too late in the cycle can miss the filing window even when they collect enough names.
Once filed, the state has to determine the validity and sufficiency of the signatures and publicly announce the result at least 60 days before the election.2Michigan Legislature. Michigan Constitution Article XII Section 2 The Board of State Canvassers handles that step, canvassing signatures and adopting ballot language for any proposal that qualifies.3Michigan Secretary of State. Board of State Canvassers
What a Petition Drive Actually Takes
Collecting roughly 446,000 valid signatures in 180 days is not a volunteer weekend project. Serious campaigns rely on paid circulators, statewide coordination, and budgets that can run into the millions. Organizers typically aim well above the legal minimum to build a cushion against invalid entries. The 2022 Reproductive Freedom for All campaign submitted about 754,000 signatures when only about 425,000 were required at the time.4Michigan House of Representatives. Ballot Proposal 3 of 2022
Timing is tight. A campaign aiming at a November ballot generally has to be collecting signatures by the prior spring, and many start earlier to leave room for the legal challenges that almost always come.
Constitutional Convention
The third path is the broadest. Under Article XII, Section 3, the question of whether to call a constitutional convention automatically appears on the ballot every 16 years. The legislature can also place the convention question before voters at any time by a two-thirds vote in each chamber.
Michigan voters last considered the question in 2010 and rejected it by a wide margin. The next scheduled vote is in 2026. If voters ever approve, delegates would be elected to draft a new or revised constitution, which would then go back to voters for ratification. Because delegates could propose changes across the entire constitution, the prospect of a convention tends to draw organized opposition from groups worried about losing existing protections.
How Ratification Works
Whichever path produces the proposal, the ratification rule is the same. It needs a majority of the voters who actually vote on that question, not a majority of everyone who shows up at the polls. On a crowded ballot, some voters skip questions they do not recognize, and those blanks do not count against the measure.
An approved amendment takes effect 45 days after the election. If voters approve two or more amendments at the same election and their provisions conflict, the one that received the most yes votes prevails.2Michigan Legislature. Michigan Constitution Article XII Section 2
Legal Challenges Along the Way
Reaching the ballot is not the same as clearing every hurdle. Opponents routinely go to court before election day. They challenge the validity of signatures, the wording of the petition, the ballot summary adopted by the Board of State Canvassers, or the argument that the proposal exceeds what a state constitutional amendment can do.
The 2022 reproductive freedom petition illustrates the pattern. Opponents argued that unusual spacing in the petition text made the language misleading. The Michigan Supreme Court ruled the spacing did not change the meaning, and the Board of State Canvassers then unanimously certified the proposal for the ballot.4Michigan House of Representatives. Ballot Proposal 3 of 2022 Campaigns planning a petition drive should treat litigation as an expected phase of the process rather than a surprise.
One structural note that comes up often: Michigan does not impose a single-subject rule on constitutional amendment petitions, so a proposal can address multiple related issues in a single measure.
Federal Limits on Any Michigan Amendment
A voter-approved amendment is not automatically the last word. Under the Supremacy Clause of the U.S. Constitution, federal law takes priority over any conflicting state provision, including a state constitutional amendment. Federal courts can strike down state amendments that violate federal protections such as the Equal Protection Clause or the First Amendment. That ceiling applies no matter which of the three amendment paths produced the change or how large the margin of approval.