Missouri voters are deciding primary races and four constitutional amendments on August 4, 2026, with two amendments drawing particular attention and heavy campaign spending ahead of election day.
The August 4 primary features more than 1,136 positions on the ballot, ranging from federal offices like U.S. House seats to state senate and house races. Polling places are open from 6 a.m. to 7 p.m. Voters must present a valid photo ID with an expiration date issued by either the federal government or the state of Missouri, though registered voters without valid ID may cast provisional ballots.
Four constitutional amendments appear on the August 4 ballot. Amendment 1 would renew an existing sales and use tax of 0.1% for 10 years to fund state parks and soil and water conservation. Amendment 2 would require the Jackson County Assessor to be an elected position rather than appointed. Amendment 3, addressing abortion and gender transition procedures for minors, is scheduled for the November 3 general election instead.
Amendments 4 and 5 Draw Campaign Focus
Amendment 4 and Amendment 5 have become the centerpiece of the August 4 primary, with Republican Governor Mike Kehoe backing both measures. Amendment 4 would significantly change how citizen-led constitutional amendments pass in Missouri. Currently, citizen-initiated amendments need only a simple statewide majority to pass. If approved, Amendment 4 would require citizen-led amendments to win a majority vote in each of Missouri’s eight congressional districts. If the amendment fails in even one district, it fails statewide. Amendments proposed by state lawmakers, however, would continue to pass with a simple statewide majority under this new rule.
Amendment 5 would overhaul Missouri’s tax structure by gradually phasing out the state income tax and giving state lawmakers the power to raise sales taxes on any goods or services. Currently, 61% of Missouri’s general revenue comes from income taxes. Under Amendment 5, lawmakers would have five years to implement new sales taxes to replace that lost revenue. The amendment does not specify which goods or services would be taxed, giving legislators broad authority to decide.
The initiative petition process that Amendment 4 targets has been used to pass major measures in recent years. Recreational marijuana, sports betting, and abortion-related amendments all passed through citizen initiatives in Missouri, according to reporting from KOMU 8 News.
County election officials have projected turnout for the primary. One county clerk said she expected turnout between 30% and 40%, though primary election turnout is historically lower than general election participation, particularly when amendments rather than high-profile federal races are the main focus.
Sources
- Ballotpedia — confirmed the four August 4 amendments and their descriptions, and that more than 1,136 positions are up for election
- KOMU 8 News — detailed Amendment 4 and Amendment 5, Governor Kehoe’s support, polling hours, voter ID requirements, and the history of the initiative petition process in Missouri
- Missouri Secretary of State — confirmed August 4, 2026 as the primary election date and polling hours
- Fox 2 St. Louis — reported turnout expectations and St. Louis County voting statistics
