by Drs. Isabel Warner and Ale Villegas Lopez
On August 4, 2026, Missourians will vote on four amendments to the state constitution. Voters will decide on:
Amendment 1: if they would like to continue funding state parks and soil and water conservation for the next ten years.
Amendment 2: how county assessors are to be elected and trained.
Amendment 4: whether to raise the approval threshold for initiative petitions to amend the constitution from a majority of all voters in the state to a majority of voters in every congressional district.
Amendment 5: to give lawmakers the power to phase out individual income tax and increase sales and use tax for any goods or services.
Continues the one-tenth of one percent (0.1%) sales and use tax for soil and water conservation and for state parks and historic sites for 10 more years and resubmits the tax to voters for approval again in 10 years. Does not create any new taxes.
Permanently ends the one-tenth of one percent (0.1%) sales tax and use for soil and water conservation and for state parks and historic sites in 2028.
Supersedes charter counties’ ability to choose whether their assessors are elected or appointed, and what training that assessor is required to complete.
In particular, this would prevent Jackson County from returning to an appointed assessor if their voters choose.
Maintains Jackson and any other charter county’s independence to elect or appoint a county assessor. Allows charter county assessors to continue determining property values without state required training.
Maintains the current statewide majority requirement for citizen-initiated constitutional amendments (>50% of votes cast).
Does not affect the already enacted prohibition of foreign nationals and foreign governments from funding ballot measure campaigns (RSMo 130.176).
Maintains the penalty for petition signature fraud at $10,000 instead of $1,000 (RSMo 116.090).
Does not create:
Requires the general assembly to reduce and eventually eliminate the state individual income tax. Once the individual income tax is eliminated, no new income tax can be implemented except by ballot initiative.
Gives lawmakers five years to:
After those five years, the General Assembly must again seek voter approval to expand taxes on services that are not taxed or substantially raise taxes on services that are already taxed.
Requires all expanded or increased sales and use taxes to be offset by a reduction in the top individual income tax rate. The top income tax rate will decrease to zero first, before lower tax bracket rates are reduced.
Requires local governments to proportionally reduce tax rates if an expansion of the sales tax base results in increased local revenue. Localities must remain revenue neutral; meaning local budgets cannot increase. However, local governments cannot reduce local funding for schools, which are primarily funded by property taxes.
Requires the reduction of all constitutional sales taxes, except the marijuana sales tax, if the legislature’s expansion of taxes on new goods and services results in additional revenue. Any new revenue generated will be offset by a reduction in other sales tax rates specified in the constitution. The auditor will be responsible for calculating the rate reductions.
Keeps the current individual income tax structure in place, with no state-mandated individual income tax phase-out. Does not:
“Shall Missouri continue for 10 years the one-tenth of one percent sales/use tax that is used for soil and water conservation and for state parks and historic sites, and resubmit this tax to the voters for approval in 10 years?
The measure allows continued collection of the existing sales and use tax, which generates revenue of approximately $140 million annually.” (Missouri Secretary of State 2026)
The Parks, Soils and Water Sales Tax is a statewide one-tenth-of-one percent (0.1%) sales tax that provides dedicated funding for Missouri state parks and historic sites along with soil and water conservation efforts (MO Department of Natural Resources (MO DNR) 2026). Missouri voters first approved it in 1984 as a constitutional amendment, which requires reapproval by voters approximately every 10 years (RSMo Article IV § 47(c) 2006, RSMo Article IV § 47(a) 1996). The tax has been reapproved each time it has come up for a vote.
Revenue from the tax is split evenly between two programs (Table 1):
Because of this funding, Missouri does not charge entrance fees to its parks and historic sites (MO DNR 2026). Missouri is one of eight states that does not charge entrance fees.
Since the tax was approved in 1984, Missouri farmers have implemented more than 288,000 conservation practices on cropland, pastureland, and woodlands (MO DNR 2026). These efforts have prevented more than 194 million tons of soil from eroding, and include grazing, irrigation, and nutrient pest management (MO DNR n.d.)
Amendment 1 does not create a new tax. The 0.1% sales tax raises approximately $140 million annually for Missouri state parks, historic sites, and conservation projects. These funds are not part of General Revenue and not subject to discretionary spending by the legislature (Article IV § 47(c)).
For more on how this tax fits into the state's broader revenue, check out the Missouri Tax Overview Science Note and the breakdown of Missouri’s State Revenue and Tax Rates.
“Shall the Missouri Constitution be amended to:
State and local governmental entities estimate no costs or savings.” (Missouri Secretary of State 2026)
Missouri’s constitution creates a special provision that counties with a charter and a population between 600,000 and 700,000 residents may appoint rather than elect their county assessors (Article VI § 18b).
Counties with a large population or strong economy can adopt a charter document that establishes a different form of government than the standard three county commissioners required by the state (Article VI § 18a). Missouri has five charter counties: Clay, Jackson, Jeferson, St. Charles, and St. Louis (Missouri Association of Counties n.d.).
Clay, Jefferson, St. Charles, and St. Louis counties do not meet the population requirement to appoint the county assessor (Federal Reserve Bank of St. Louis 2025). By 2020, Jackson County also surpassed 700,000 residents (Federal Reserve Bank of St. Louis 2026). In November 2025, Jackson County voted to make the Jackson County Assessor an elected position (Jackson County Election Board 2025).
County assessors determine the value of property for the calculation of property taxes (Boone County Government n.d., Figure 1). Assessed property may include land, structures, and motorized vehicles. To learn more about how property is assessed, see the Science Notes AI and Property Assessments, Agricultural Property Taxes, and Property Taxes & Home Values, and Property Tax Assessment Limits.
County assessors must be certified by the state to assess property for tax purposes (RSMo 53.255). To do so, they must complete 32 hours of classroom instruction on property tax assessments, and complete at least one additional course every two years to maintain their certification (State Tax Commission of Missouri 2029). Charter count assessors are not explicitly required to complete any training required by state law.
State and local governmental entities estimate no costs or savings.
For more information on how property taxes are calculated and how aspects of assessments affect owners, see MOST's Science Notes on Property Taxes and Home Values and Property Tax Assessment Limits.
“Shall the Missouri Constitution be amended to:
The Department of Corrections estimates increased annual costs of up to $21,817. The Office of State Public Defender estimates an unknown fiscal impact. Other state governmental entities estimate no costs or savings. Local governmental entities estimate no costs or savings.” (Missouri Secretary of State 2026)
Constitutional amendments are approved when a simple majority (>50% of votes cast) of voters across the state vote to approve (MO Secretary of State’s Office 2025).
Citizens and the legislature can place constitutional amendments on the ballot (Article XII § 2(b)). The process to place amendments on the ballot is slightly different for each.
Regardless of how a constitutional amendment is proposed, it must obtain >50% of votes cast to become law (MO Secretary of State’s Office 2025).
Learn more about the Initiative Petition Process, Initiative Petition Impacts, and how State Requirements for Initiative Petitions vary across the country.
Petition signature fraud is already illegal in Missouri (RSMo 116.090). Petition signature fraud includes:
Petition signature fraud is punishable by up to one year in jail and/or a $10,000 fine.
Foreign nationals and foreign governments are presently banned from funding ballot measure campaigns (RSMo 130.176).
The Department of Corrections estimates increased annual costs of up to $21,817 and the Office of State Public Defender cannot estimate the impact.
Printing and mailing the full text of each petition would cost the state approximately $1 million every other year (HJR 3 2025).
It is unclear whether and how much public hearings on initiative petitions would cost the state.
Other state entities, along with local governments, estimate no fiscal impact.
“Shall the Missouri Constitution be amended to:
The proposal has no direct impact on state or local tax revenue. If passed, implementing legislation will have an unknown impact to state and local tax revenue. If implemented, state government entities expect a reduction of $57,000 annually in income tax check-off donations and implementation costs of at least $100,000.” (Missouri Secretary of State 2026)
The General Assembly defines income for state tax purposes and has the power to set the state income tax rate (Article X § 4(d)). Nothing prohibits the General Assembly from reducing the income tax rate to zero, effectively eliminating the individual income tax.
However, the Assembly is prohibited from creating new taxes on services that are not already taxed without voter approval (Article X § 26). It is also prohibited from raising any taxes to generate more than $50 million of revenue without voter approval (Article X §18(e)). Sales and use taxes on vehicles and fuel, and registration fees must be collected separate from General Revenue and utilized by the state, cities, and counties to build and maintain transportation infrastructure (Article IV § 30 (b), § 30(c), § 30(d)).
If the General Assembly collects revenues in excess of the limits established by the Hancock Amendment, it must refund that amount to taxpayers in that fiscal year (Article X § 18). It is not required to adjust tax rates.
Similarly, local governments cannot have windfall or surplus budget revenue (Article X § 22). To remain revenue neutral, they must reduce tax rates to generate the same amount of revenue as previous fiscal years. They also must seek voter approval for increases in taxes and fees.
Missouri schools are funded through a combination of local property taxes, state sales taxes (Proposition C), state gambling and tobacco taxes, federal monies, and state general funds (see Science Note: Education Funding Sources). In 2025, approximately half of state education funding came from the state’s General Revenue fund, with the other half from federal funds and specific lottery, bingo, gaming, and tobacco taxes (MO House of Representatives 2024). In 2021, the state supported 32% of per-student funding, while localities contributed the other 68% (MO Auditor 2021).
In Fiscal Year (FY) 2025, Missouri collected $9.17 billion in individual income taxes (MO Office of Administration 2025). Individual income taxes made up more than 60% of the state’s $15.2 billion gross revenue in FY25.
Since 2003, individual income taxes have comprised at least 62% of General Revenue each year (see Science Notes: History of MO Taxes, State Revenue & Tax Rates, Figure 3). On average over the past five years, Missouri has collected a higher portion of its state General Revenue from individual income taxes (>65%) than other states that have eliminated income taxes (<45%, see Science Note Pre-Elimination Income Tax Rates, Figure 4, Figure 5).
If passed, lawmakers will have five years to enact legislation to gradually eliminate income tax. This will also eliminate about 60% of Missouri General Revenue. To make up for this lost revenue, lawmakers will enact state and local sales and use tax increases by a combination of increasing tax rates on current services and expanding the number of services that are taxed.
For background on Missouri's income tax structure and proposed income tax elimination, see MOST's Science Notes on the History of Missouri Taxes, Missouri Tax Overview, Income Tax Elimination, and Pre-Elimination Income Tax Rates.
For more information on school funding see Science Notes on Federal Education Funding and state Education Funding Sources.
Last day to register to vote: July 8, 2026
Last day to request absentee ballot: July 22, 2026
Early voting or no excuse absentee voting dates: July 21-August 3, 2026
To check your voter registration status: https://voteroutreach.sos.mo.gov/portal/
Note that early voting or no excuse absentee voting locations may not be your assigned polling place.
For general elections and voting information: https://www.sos.mo.gov/elections/calendar/2022cal
For more on how this tax fits into the state's broader revenue, check out the Missouri Tax Overview Science Note and the breakdown of Missouri’s State Revenue and Tax Rates.
For more on property assessment, see:
Learn more about the Initiative Petition Process, Initiative Petition Impacts, and how State Requirements for Initiative Petitions vary across the country.
For background on Missouri's income tax structure and proposed income tax elimination, see MOST's Science Notes on:
For more information on school funding see Science Notes on Federal Education Funding and state Education Funding Sources.