Tuesday’s vote would make Missouri the first state to require citizen-led constitutional amendments to win 50% support in all eight congressional districts, not just a statewide majority.
That standard would have blocked recent measures on abortion rights, marijuana, sports betting and Medicaid expansion, all of which passed statewide with 53% or less between 2020 and 2024.
Republican backers say the rule would force broader geographic consensus and curb campaigns powered by big margins in St. Louis and Kansas City plus out-of-state money.
Critics say a slim loss in one district could override strong support elsewhere, creating a dual system because legislatively referred amendments would still pass with a simple statewide majority.
More than 300,000 signatures are already being verified for a possible November amendment that would restore majority-rule standards and further shield Missouri’s initiative process.