A state constitution can be amended in four ways: a proposal from the state legislature, a citizen-initiated ballot measure, a constitutional convention, or, in a few states, a constitutional commission. Legislative proposals account for roughly 80 percent of the amendments voters see each year. About a third of states also allow citizens to propose amendments directly, and any state can call a convention. With one exception, every method ends the same way: voters have the final say.
Amendments Proposed by the Legislature
The standard path begins as a joint resolution introduced in the state legislature. Both chambers must pass it, but the vote threshold is where states diverge sharply.
About 14 states allow a simple majority in a single session to send an amendment to the ballot. Another 25 require a supermajority in a single session — 9 of those at three-fifths, and 16 at two-thirds. The remaining 11 states require a majority vote in two consecutive sessions, so an intervening election lets voters weigh in on the lawmakers who will cast the second vote. Four of those states also offer a shortcut: a supermajority in one session substitutes for the two-session requirement.
The governor is usually not part of this. State constitutions typically withhold the veto over proposed amendments, so once the legislature clears the required margin, the proposal heads straight to the ballot without a signature.
What Counts as Voter Approval
Every state except Delaware requires voters to approve a legislatively proposed amendment. Delaware instead demands a two-thirds vote in two consecutive legislative sessions and skips the public entirely. For the other 49 states, the question is what kind of majority is enough.
Most states set the bar at a simple majority of voters who cast a ballot on the amendment question. Eleven states demand more:
- New Hampshire requires a two-thirds vote on the question, Florida requires 60 percent, and Colorado requires 55 percent.
- Minnesota and Wyoming require a majority of everyone who voted in the election, not just those who voted on the amendment. Skipping the question functions as a “no.”
- Illinois requires either 60 percent of votes cast on the question or a simple majority of everyone who voted for any office. Tennessee requires both a majority on the question and a majority of all voters casting ballots for governor. Hawaii, Massachusetts, Mississippi, and Nebraska each combine minimum vote counts with turnout formulas.
Where a blank counts against the amendment, supporters need not just favorable votes but engagement on the question itself.
Citizen-Initiated Amendments
Eighteen states let citizens propose constitutional amendments directly, bypassing the legislature. This route puts issues on the ballot that lawmakers may be unwilling to touch.
Filing and Ballot Language
Proponents draft the amendment text and file it with a designated state official, usually the attorney general or secretary of state. That office checks the proposal against legal requirements before signature gathering can begin, and in most states also prepares the ballot title and summary that will appear on the petition and later on the ballot.
Collecting Signatures
Once petitions can circulate, supporters face the hardest part: collecting enough valid signatures from registered voters. Every state ties its threshold to a percentage of votes cast in a recent statewide election. Massachusetts sets one of the lowest bars at 3 percent of votes in the last gubernatorial election. Arizona and Oklahoma sit at 15 percent. Most states land somewhere in the 8 to 10 percent range.
Raw totals are not always enough. More than a dozen states impose geographic distribution requirements so that no proposal qualifies on the strength of one or two population centers. Florida requires signatures equal to 8 percent of the district-wide vote in at least half of its congressional districts. Colorado requires signatures from 2 percent of registered voters in each of its 35 state senate districts. Missouri requires signatures from two-thirds of its congressional districts. These rules force proponents to demonstrate statewide reach.
Most serious campaigns hire professional circulators, and states regulate the practice. Some require paid circulators to register or disclose their paid status; some ban per-signature pay and require hourly or flat-rate compensation.
The Single-Subject Rule
Eighteen states apply a single-subject rule to citizen initiatives, requiring each proposal to address one topic. The rule blocks logrolling — bundling an unpopular provision with a popular one so voters cannot accept one without the other — and keeps voters clear on what they are approving.
Consequences vary. A court may strike the whole measure or sever the offending part. In some states, the official who reviews the proposal will reject a multi-subject filing before petitions circulate. In others, the challenge comes after the measure qualifies or even after voters approve it, which means a court ruling can undo months or years of work.
Constitutional Conventions
A constitutional convention assembles delegates with authority to propose broad revisions or a new constitution outright. The method has fallen dormant; no state has held one since the 1980s.
Calling a Convention
A convention typically requires two steps. The legislature places the question of whether to hold one on a statewide ballot, and voters then decide. Some states require a supermajority legislative vote to refer the question; others need only a simple majority.
Fourteen states skip the legislature through automatic ballot referral, with their constitutions requiring the question to appear at fixed intervals. Alaska, Hawaii, Iowa, New Hampshire, and Rhode Island put it to voters every 10 years. Michigan uses a 16-year cycle. Connecticut, Illinois, Maryland, Missouri, Montana, New York, Ohio, and Oklahoma use a 20-year cycle. Voters in these states have consistently rejected the call in recent decades.
Choosing Delegates and Ratifying the Work
If voters approve a convention, delegates come next. The most common approach elects them from existing legislative or representative districts so every part of the state has a voice. Some states peg the convention’s size to the legislature, others set their own number, and a few leave the details for the legislature to fill in after the vote. Whatever the convention proposes still has to go to voters for ratification. The convention cannot change the constitution on its own.
Constitutional Commissions
Constitutional commissions are the most indirect route. A commission is a body appointed by the governor, the legislature, or another state entity to study the constitution and recommend changes. In nearly every state, commissions are advisory. They produce reports and draft language, but the legislature decides whether to act, and any resulting amendment still moves through the standard legislative process and voter approval.
Florida is the exception. Its constitution authorizes two commissions that can put amendments directly on the ballot without legislative approval. The Constitution Revision Commission meets every 20 years and can propose amendments on any topic. The Taxation and Budget Reform Commission runs on a staggered 20-year schedule, so one of the two convenes roughly every decade. No other state gives commissions this direct ballot access.
Federal Limits on State Amendments
State constitutions operate under the U.S. Constitution. The Supremacy Clause makes federal law override any conflicting state law, including state constitutional provisions. An amendment that conflicts with federal constitutional rights can be struck down in court no matter how large the margin of approval.
The clearest example is the Supreme Court’s 1996 decision in Romer v. Evans. Colorado voters had approved Amendment 2, which barred any state or local government entity from enacting protections based on sexual orientation. The Court struck it down under the Fourteenth Amendment’s Equal Protection Clause, holding that the provision imposed a broad disability on a single group and served no legitimate government interest. Voter approval does not immunize a state amendment from federal review.
When an Approved Amendment Takes Effect
After voters approve, most states require the results to be officially certified before the change takes effect, usually within weeks of the election. Some amendments set their own effective date to give the legislature time to pass enabling laws or agencies time to prepare. Without a specified date, the amendment generally becomes part of the constitution as soon as results are certified. Amendments that require new spending, create new agencies, or restructure government functions usually need follow-up legislation to become fully operational, even after the constitutional text is in force.