Both campaigns are selling fear. This is a plain reading of what Amendment 5 would actually do, who stands to gain, who would pay more, and why the drafting and the timing of the vote deserve as much scrutiny as the tax policy.
If you have listened to the radio in Missouri this summer, you have heard both sides of the Amendment 5 debate warn of dire consequences. Supporters present the elimination of the state income tax as a straightforward good that will keep more money in residents’ pockets. Opponents warn that sales taxes will climb sharply, taxing goods and services that have never been taxed before. The reality is more complicated than either campaign is willing to say in thirty seconds, and the purpose of this article is to set the advertising aside and explain what the measure would actually do.
The essential point is this. Amendment 5 does not, by itself, cut anyone’s taxes or set anyone’s rate. It rewrites the rules under which the Missouri General Assembly may tax its citizens, and it leaves the most consequential decisions, including which services are taxed and at what rate, to be made by the legislature after they vote for it. That single fact explains why both campaigns can make sweeping and contradictory claims, and it is the reason the measure warrants a careful read before anyone votes.
What the ballot says
This is the official summary voters will see, in full:
- Phase-out the individual income tax based on revenue growth;
- Reduce personal property and other local taxes when local revenues increase;
- Modify the sales and use tax to eliminate income tax and reduce local taxes; and
- Protect local funding for public schools and other purposes?”
But the full text of the resolution – which you can view here – is quite different than this simplification.
This is confusing on purpose. The way this legislation is worded means that the legislature has full control of both Missouri personal income tax, and also the ability to increase the sales tax, but the catch is that the sales tax has to be raised, and only after the revenue of Missouri is increased, can they reduce the income tax rate. Missouri currently has a state sales tax rate of 4.225%, with many municipalities having an overall sales tax rate between 7.5% and well over 10%. Currently Missouri collects between 65% and 68% of its general revenue fund from income taxes, and further, income taxes make up 28.2% of the states tax revenue, while sales taxes generate 28.3% of the tax revenue. The numbers are pretty clear, if sales taxes currently generate the same amount of revenue as the income tax – this means to compensate for this, they will need to double the sales tax rate.
What Amendment 5 would do
The measure has four operative parts.
It phases out the individual income tax. Missouri’s individual income tax currently supplies about $8.5 billion a year to the state. Under Amendment 5, whenever state revenue grows beyond a set threshold, the surplus would be used to cut the income tax rate. Each reduction in income tax is permanent, and once the rate reaches zero the constitution would bar the state from ever reimposing an income tax.
Sales tax rates must be increased to prove that income tax rates can be lowered.To make this work, sales taxes have to be increased before the state – and at the legislatures sole option – could lower the income tax rate. The common sense takeaway here is that you will be double taxed.
It suspends voter approval of additional taxes for 5 years.This is what I view as a problem. Under Missouri’s Hancock Amendment, a significant state tax increase normally requires a vote of the people. Amendment 5 opens a five-year window in which the General Assembly could expand and increase sales taxes without a public vote. This is also a scary provision in this bill, it gives the legislature, that drafted this confusing and poorly worded Amendment – likely because they are not lawyers – to have carte blanche for 5 years to do whatever they want.
It changes how local sales-tax growth is handled. When a city or county’s sales-tax revenue rises, the amendment would require local (city / county) rates be reduced proportionately, but also prevents property taxes (school funding) from being reduced. What this means is that if your city needs additional money for police, fire, EMS, they now have a set bar as to how much they can get from sales taxes – and that is a majority of the funding for this services.
Annual income-tax revenue to be phased out
Share of state general revenue it provides
Sales taxes may rise without a public vote
Why the vote is in August, not November
One of the most scary things in this Amendment is when it is voted on. It is the date. Governor Mike Kehoe placed the tax overhaul on the August 4 primary ballot rather than the November general election. This means that fewer voters will turn out, and those that are pushed on this issue will show up in the primaries. Missouri allows this, and while many people are thinking this will be on the general ballot, it will be decided in the primary which is also concerning.
Critics have made this point bluntly. Scott Charton, a spokesman for the opposition, called Amendment 5 “the most brazen power grab from our citizens on a single ballot in Missouri history” and argued that the August date was chosen precisely to keep the measure off a crowded fall ballot. Early voting this summer has been heavier than usual, which may narrow the turnout gap, but the structural reality remains: fewer Missourians will decide Amendment 5 in August than would have decided it in November. Voters can reasonably weigh that choice of timing as part of the measure itself.
Who benefits, and who pays more
Because a sales tax takes a larger share of a lower income than a higher one, replacing an income tax with a sales tax generally shifts the overall burden downward. Independent analyses of Amendment 5 reach that conclusion. The Institute on Taxation and Economic Policy and the Missouri Budget Project, which each modeled the swap, project that the largest benefits flow to the highest earners, while most Missourians would pay more overall once the new sales taxes are accounted for.
Who tends to benefit
High earners and the wealthiest households, who pay the most income tax today and would see the largest cut. Owners of high-income businesses. Households whose income comes from sources that a sales tax reaches only lightly.
Who tends to pay more
According to those analyses, a household earning between roughly $50,000 and $80,000 would pay about $535 more per year on net, with upper-middle earners paying closer to $1,600 more. Seniors would pay about $365 more on average, a collective increase of roughly $335 million, because Social Security, military pay, and public pensions are already exempt from Missouri income tax, so retirees gain little from repeal while still paying higher sales taxes. Working families and renters, who spend most of what they earn, would feel the sales-tax increase most.
Supporters dispute those figures. State Representative Bishop Davidson, among others, argues that the average Missouri wage earner would come out roughly $2,800 ahead each year once the income tax is gone. That estimate, however, measures the income tax a household would stop paying without fully accounting for the new sales taxes it would begin paying, and it assumes the income tax reaches zero, which the amendment ties to years of future revenue growth. The gap between the supporters’ $2,800 and the analysts’ figures exists largely because the amendment never fixes the one number that would settle the question: the sales-tax rate.
What each campaign is claiming
With the substance in view, the advertising is easier to evaluate. Both sides make claims that are technically grounded but incomplete.
The case for it
Supporters emphasize eliminating the income tax, a projected gain for the average wage earner, and the assurance that the amendment cannot itself raise taxes.
In context: It is accurate that the amendment sets no rate and therefore does not directly levy a tax. It is also the instrument that authorizes the legislature to raise sales taxes for five years without a public vote. The projected household gain counts the income tax removed but not the sales taxes added, and the phase-out depends on sustained revenue growth rather than taking effect at once. Even supporters acknowledge that in the first year residents would pay both the income tax and higher sales taxes.
The case against it
Opponents warn that sales taxes would roughly triple, reaching a combined rate near 16 percent on nearly everything, and that most Missourians would pay more.
In context: The amendment sets no rate, so it cannot by itself triple anything. The 16 percent figure is a projection of the rate that would be required if lawmakers chose to replace all of the lost income-tax revenue through sales taxes on a broad base of goods and services. It is a credible worst case and a fair warning, but it describes a future legislative choice rather than a certainty written into the amendment.
This article is offered for general educational purposes and reflects the author’s analysis of the measure’s text, drafting, and context. It is not an endorsement of or opposition to Amendment 5, and reasonable people disagree about its merits. Nothing here is legal, tax, financial, or voting advice, and reading it does not create an attorney-client relationship. Voters should read the full official ballot language and rely on the Missouri Secretary of State for authoritative election information. Figures and statements are drawn from the official ballot summary (SS SCS HCS HJR 173 & 174), the Institute on Taxation and Economic Policy, the Missouri Budget Project, statements by supporters and opponents of the measure, and reporting by the Missouri Independent, KCUR, KSMU, and KOMU (2026).