In 2026, Missouri voters will decide on a constitutional amendment, Amendment 4, to require voter approval of citizen-initiated constitutional amendments in each congressional district, rather than statewide.

Amendment 4 was introduced by State Rep. Ed Lewis (R-6). It passed the House by 98–58 and passed the Senate by 21–11. In addition to the new supermajority requirement, the amendment would also add a prohibition on foreign nationals contributing to ballot measure campaigns to the state constitution, among other provisions.

Currently, 11 states require supermajority approval for certain ballot measures—for example, a 60% vote to amend the constitution or a higher threshold for tax-related amendments. While four states, including Missouri, require signatures to be collected from a certain number of congressional districts, none require voter approval in each congressional district. Amendment 4 would create a new type of ballot measure supermajority requirement.

However, all recent citizen-initiated constitutional amendments would have failed under the proposed measure.

Missouri currently has eight congressional districts. Two—Missouri’s 1st and 5th—are represented by Democrats, while the remaining six—Missouri’s 2nd, 3rd, 4th, 6th, 7th, and 8th—are represented by Republicans.

Four of Missouri’s most recent citizen-initiated constitutional amendments—a Medicaid expansion amendment in 2020, a marijuana legalization amendment in 2022, and two amendments in 2024: one that legalized sports wagering, one that established the right to an abortion—all passed the statewide simple majority vote (one amendment, Amendment 5, failed in 2024). Ballotpedia used one sample congressional district, Missouri’s 7th District, to compare total yes votes and no votes in the 7th District to the statewide totals. The 7th District was selected because the secretary of state provides election results by county, not congressional district, and the majority of the 7th District’s counties fall inside the congressional district borders (with the exception of Webster County, which was excluded from the analysis). All amendments in Missouri’s 7th Congressional District were defeated.

This means that under Amendment 4, all these recent initiatives that passed would have failed.

In the same special session where the state legislature voted to refer Amendment 4 to the ballot, the legislature also passed a new congressional map. Gov. Mike Kehoe (R) signed the new map into law. President Trump said the map would “deliver a gigantic victory for Republicans in the ‘Show Me State,’ and across the country” and provide an “… opportunity to elect an additional MAGA Republican in the 2026 Midterm Elections.” The new congressional map would make its most significant changes, in terms of partisanship, in the Kansas City area. However, signatures are currently being gathered for a referendum effort to place the map on the 2026 ballot, which means it would not go into effect unless approved by voters.

Voters will decide Amendment 4, along with three other constitutional amendments, on Nov. 3, 2026.