Judge to decide whether Missouri tax overhaul stays on August ballot

Missouri’s Amendment 5, a proposal to replace the state income tax with expanded sales taxes, faces a June 9 court deadline to determine if it remains on the August 4 ballot. Governor Mike Kehoe added the measure to the primary ballot last week, but opponents filed a lawsuit arguing it violates the Missouri Constitution’s single-subject rule. Circuit Judge Christopher Limbaugh will rule on the case, with appeals possible before the ballot deadline. The proposal, if approved by voters, would allow lawmakers to expand sales tax to any goods or services or increase rates without voter approval. It would also exempt the new sales tax from requirements that motor fuel taxes fund highways and redirect state auditor authority to set rates for conservation-related sales taxes. The amendment uses the word 'notwithstanding' to override other constitutional provisions, a legal tactic opponents call unconstitutional. Opponents argue the amendment violates the single-subject rule by altering multiple constitutional sections, while the attorney general’s office claims it only amends the taxation section. Passage of Amendment 5 is Governor Kehoe’s top priority for 2026. Three committees—one supporting and two opposing—are preparing multimillion-dollar campaigns. The pro-Amendment 5 group, Missouri Promise, received a $1.9 million donation from Missouri Promise Inc., a Delaware-based nonprofit. Opposition groups include Missourians for Fair Taxation, funded by the Missouri Association of Realtors, who oppose the proposal’s impact on constitutional provisions they previously secured.