Missouri Amendment 4 Would Restrict Ballot Initiative Process

Signature Requirements Would Double in Practice

Amendment 4 would require petition signatures equal to 8% of votes cast in the last gubernatorial election from at least six of Missouri's eight congressional districts, up from the current 5% threshold across six districts. Under current law, initiatives need roughly 171,000 valid signatures. The new threshold would push that figure above 275,000 based on 2024 turnout data.

The measure also mandates a 60% supermajority for passage of any constitutional amendment placed on the ballot by citizens. Legislative referrals would remain subject to simple majority approval.

Missouri's existing initiative process, established in 1908, has produced 71 citizen-led constitutional amendments reaching the ballot. Fourteen passed. That includes medical marijuana legalization in 2018 and adult-use cannabis in 2022.

Fiscal Impact Statements Would Require State Approval

Every petition would need to include a fiscal impact statement prepared by the state auditor before signature collection begins. Current law allows campaigns to begin gathering signatures immediately after filing. The new requirement would add an estimated 60-90 day delay to the front end of every campaign.

The auditor's office would gain authority to determine whether a proposed measure carries fiscal consequences for state or local governments. Campaigns challenging those determinations would face litigation before signature drives launch.

That procedural shift matters for cannabis policy. Both Amendment 2 (medical, 2018) and Amendment 3 (adult-use, 2022) carried fiscal impact disputes during signature phases. Amendment 4 would move those fights earlier. It makes them mandatory hurdles.

Cannabis Reform Campaigns Face Higher Bar

If Amendment 4 passes, future cannabis policy changes via ballot initiative would require 60% voter approval and signatures from rural districts where cannabis measures historically poll weakest. Amendment 3 passed with 53.1% statewide support in 2022 but failed to reach 50% in five of Missouri's eight congressional districts.

The cleanest read on Amendment 4? It's designed to block the kind of narrow-majority wins that delivered both medical and recreational cannabis in Missouri. Advocates hoping to pursue expungement expansions, home-grow increases, or social equity reforms through the ballot would face a materially harder path.

For full background on this story, see the CannIntel topic hub on Missouri ballot initiative reform.

Amendment 4 appears on the November 5, 2026 general election ballot. Polling conducted in June 2026 by the Missouri Independent showed 48% support, 39% opposition, and 13% undecided. Simple majority approval would make it law.