The certification of Proposition A for Missouri’s November 3 ballot has placed a veto referendum on the 2025 Republican-drawn congressional map (HB 1) before voters, with a “yes” vote required to uphold the new lines and a “no” vote to retain the prior 2022 boundaries. Trader consensus favoring rejection at 57 percent reflects the measure’s origin as a mid-decade partisan adjustment, the collection of more than 300,000 signatures by opponents, and Missouri’s precedent of using referendums to block legislative redistricting plans. Recent state Supreme Court rulings cleared procedural hurdles and suspended the new map pending the vote, while federal appeals continue without altering the ballot status. Upcoming campaign activity and turnout patterns among key voting blocs will shape final probabilities ahead of election day.