Missouri Voters Reject GOP Tax Amendment and Constitutional Change Measure in August Primary

Missouri voters on August 6, 2026 defeated Amendment 5, a Republican-backed tax overhaul supported by $23 million in outside funding, by 67 percentage points, losing in every county. The same electorate approved Amendment 1, renewing a sales tax for state parks, with 82% support, and rejected Amendment 4, which would have required constitutional amendments to pass in every congressional district, with less than 20% voting yes. The results suggest Missouri voters can distinguish between ballot measures despite concerns from state officials about out-of-state influence and voter confusion.