Missouri voters face Proposition A on November 3, 2026, a veto referendum on House Bill 1, the congressional map enacted during a 2025 special session and signed by Governor Mike Kehoe. The measure would uphold new district lines drawn outside the standard decennial cycle to increase Republican seats from six to seven by splitting Kansas City across multiple districts. A citizen group collected more than 300,000 signatures to place the referendum on the ballot after prolonged litigation. The Missouri Supreme Court ruled unanimously in September 2026 that the referendum is constitutional, blocked immediate use of the new map for the 2026 election, and ordered it placed before voters. Traders assign the highest probability to rejection, consistent with Missouri’s prior voter record of using referendums to overturn legislative redistricting plans and the measure’s partisan origin.