The proposed amendment to the Constitution of the State of Iowa introduces a new section in Article XIII that establishes a requirement for a two-thirds majority vote in the General Assembly for any changes to state tax laws. Specifically, any bill that seeks to increase the individual income tax rate, corporate income tax rate, or any other tax based on income or legal and special reserves must receive affirmative votes from at least two-thirds of the members elected to each house. Additionally, the same two-thirds majority is required for bills that establish new taxes on any type of income or legal and special reserves imposed by the state.

Furthermore, the amendment stipulates that any lawsuit challenging the proper enactment of such a bill must be filed within one year of its enactment; otherwise, the bill will be considered properly enacted. Each bill subject to this requirement must include a provision detailing the enactment requirements. The General Assembly is also tasked with enacting laws to implement this amendment. If approved, the amendment will be submitted to Iowa voters for ratification during the general election in November 2026.