Missouri ballot-measure ads have pulled in $26.7 million this year, and Amendment 4 Missouri sits inside the fight that has dominated the airwaves months before the election. Amendment 5 has drawn the most attention and dollars, turning two constitutional amendments into the center of the state’s advertising push.
Ryleigh Hindle wrote the Missouri story on July 31, 2026. The spending total covers various groups, and the split matters because one amendment would change the initiative petition process while the other would give lawmakers new taxing authority.
Amendment 4 Missouri ballot fight
Amendment 4 would change the state’s citizen-led initiative petition process. A measure would have to pass in all eight congressional districts instead of by a simple statewide majority.
That change would not reach items legislators put on the ballot. Those measures would still need only a simple statewide majority to pass, which leaves two different rules on the books depending on who puts the question before voters.
Amendment 5 and HB 173
Amendment 5 was placed on the ballot through HB 173. It would direct lawmakers to pass additional legislation with the goal of eliminating the state’s income tax.
The proposal would also grant lawmakers the authority to raise the state sales tax and expand the base of goods and services that can be taxed without needing additional voter approval for five years. Currently, most services are not taxed, and lawmakers must get approval from voters for sales tax changes.
Competing claims in Missouri
That is why the ad war has sharpened around Amendment 5. Proponent ads say taxpayers would keep more money they’ve earned, while opponent ads warn of catastrophic consequences to taxpayer pocketbooks and state funding.
For voters, the practical divide is direct: Amendment 4 would make the path for citizen petitions harder, while Amendment 5 would broaden lawmakers’ taxing power and change the sales-tax base without another vote for five years. The unanswered piece is how much additional sales-tax authority Amendment 5 would create in practice.
