Missouri Amendment 6 passes, setting 80% bar to change voter-passed laws

Missouri voters approved Amendment 6 on Tuesday, Nov. 3, adding new protections for citizen-led ballot initiatives and making it harder for lawmakers to change measures approved by voters.

The Missouri Independent reported the measure’s passage late Tuesday. With 98.4% of expected votes counted, the amendment received 60% support, or 1,251,555 votes, while 40%, or 835,585 votes, opposed it, as of 1:17 a.m. EST Wednesday, according to The New York Times.

Amendment 6 requires an 80% vote in both chambers of the Missouri Legislature, plus another statewide vote, to change laws and constitutional amendments passed by initiative since 2010. It also bars lawmakers from making the initiative petition process more difficult, including by raising signature requirements or shortening the time available to gather signatures.

The outcome is a victory for supporters of direct democracy, who argued that lawmakers should not be able to easily undo policies adopted by voters. The amendment comes as Missouri’s initiative and referendum process has become a major battleground over issues including abortion rights and congressional redistricting. Voters on Tuesday also rejected Amendment 3, the legislature’s measure to repeal the 2024 abortion rights amendment.

They rejected Proposition A the same day, blocking the Republican-drawn congressional map lawmakers passed in 2025 and keeping the state’s 2022 map in place.

Amendment 6 could shape what happens next. It bars lawmakers from passing legislation similar in effect to a law voters rejected by referendum unless 80% of both chambers send it back to voters. Legal experts have said that could make another mid-decade redraw much harder, but the amendment does not define “similar in effect,” according to reporting by the Missouri Independent.

Lawsuits are expected. St. Louis Public Radio reported that one target could be the provision applying the new standard to citizen-backed measures passed since 2010. Benjamin Singer, a co-founder of Respect Missouri Voters, said he is confident the amendment will withstand legal scrutiny.