On November 3, Iowans will consider a proposed change to their Constitution: Amendment One, which would establish a two-thirds legislative majority to increase state income tax rates. The amendment’s appearance on the ballot represents the culmination of a legislative process that began more than two years ago.
Amending Iowa’s Constitution is no simple task. Unlike an ordinary law, which can generally be passed during a single legislative session, a constitutional amendment must clear several hurdles over multiple years before voters ever have an opportunity to consider it. That’s by design. Iowa’s Constitution establishes the fundamental framework of state government and protects certain rights of its citizens. Changing that document is supposed to require more time, deliberation, and sustained legislative support than passing an ordinary law.
The results speak for themselves. Since 1980, Iowa voters have considered only 18 proposed constitutional amendments. Of those, 14 were approved and four were rejected. Constitutional amendments don’t appear on Iowa ballots very often, but when they do, voters have historically been inclined to approve them.
How Iowa’s Constitutional Amendment Process Works
Article X of the Iowa Constitution says that a proposed amendment must receive majority approval from both the Iowa House of Representatives and Iowa Senate during two consecutive General Assemblies. A General Assembly spans two years, meaning a legislative election must take place between the first and second rounds of approvals. That requirement gives voters an opportunity to elect new lawmakers before the proposed amendment receives its second legislative consideration.
The process also requires that lawmakers approve the exact same language both times. If the second General Assembly makes changes to the proposal, the process starts over. Lawmakers can ordinarily negotiate, revise, and amend legislation as it moves through the House and Senate. But a constitutional amendment receiving its second legislative approval cannot simply be rewritten without jeopardizing the work completed during the previous General Assembly.
Once both General Assemblies approve the proposal, it is submitted to Iowa voters. The governor does not sign or veto constitutional amendments, and a simple majority of those voting on the question determines whether the proposed change becomes part of the Constitution. The process is intentionally demanding. It requires support from lawmakers across two different General Assemblies, an intervening election, and ultimately the consent of Iowa voters.
Amendment One’s Journey to the Ballot
Amendment One offers a timely example of how this process works.
The proposal began its legislative journey in 2024, when the House introduced House Study Bill 721 on February 20. After advancing through the committee process, it became House Joint Resolution 2006. On March 26, 2024, the Iowa House approved the resolution by a vote of 61–35. The Iowa Senate followed on April 10, approving it 31–13. With both chambers having agreed to the proposal, Amendment One completed its first round of legislative approval.
The November 2024 election then provided the required opportunity for voters to elect a new General Assembly.
During the 2025 legislative session, the Senate again took up the proposal, this time as Senate Joint Resolution 11. On April 15, 2025, senators approved it by a vote of 32–15. The House did not take its final vote until May 2, 2026, when representatives approved the resolution 57–21.
That final House debate illustrates why the constitutional amendment process is different from ordinary lawmaking. Several amendments to the resolution were proposed, but none were adopted. Some were ruled not germane, while others were defeated. Had lawmakers changed the constitutional language that had already received approval in 2024, the revised proposal would have needed to begin the process again.
Instead, the House approved the proposal without changing the language, completing the second round of legislative approval and clearing the way for Amendment One to appear on the November 3, 2026, ballot. If approved by voters, Amendment One would be effective immediately, heading into a 2027 legislative session with a new governor in office and new legislators serving in the Iowa House and Senate.
A Look at Iowa’s Recent Constitutional History
Amendment One joins a relatively short list of proposed constitutional changes that have reached Iowa voters in recent decades. The state’s current Constitution was adopted in 1857 and has been amended just 51 times.
Looking specifically at the period from 1980 through 2024, Iowa voters considered 18 amendments over 12 different election years. Fourteen passed, while four failed.
Those amendments addressed a wide variety of subjects, including technical changes in how state government operates, such as the 2024 amendment that clarified the Governor-Lieutenant Governor succession process. Other amendments have addressed much more substantive policy questions, like the 2022 amendment approved by Iowans that placed the right to bear arms into our state’s Constitution. And some proposed changes addressed language that had simply become outdated. In 1992, voters approved removing a constitutional provision that disqualified individuals involved in dueling from holding public office.
Constitutional Amendment History
1980 – Present
| 2024 | Citizenship voting requirements | Pass |
|---|---|---|
| 2024 | Executive branch succession | Pass |
| 2022 | Right to own and bear arms | Pass |
| 2010 | Natural Resources sales tax | Pass |
| 2008 | Criminal convictions & voting rights | Pass |
| 1999 | Balanced budget requirement | Fail |
| 1999 | Supermajority tax increase requirement | Fail |
| 1998 | Gender issues constitutional rights | Pass |
| 1998 | Jury rules | Pass |
| 1996 | Hunting and fishing fees | Pass |
| 1992 | Gender issues constitutional rights | Fail |
| 1992 | Dueling bans and elected office | Pass |
| 1988 | Executive branch elections | Pass |
| 1988 | Executive branch duties | Pass |
| 1986 | Effective dates of legislation | Pass |
| 1984 | Administrative rulemaking provisions | Pass |
| 1984 | Public education funding distribution | Pass |
| 1980 | Gender issues constitutional rights | Fail |
In 1999, Iowa voters considered a taxpayer protection measure similar to Amendment One, with 52 percent of them rejecting a proposal requiring a three-fifths legislative majority to increase certain taxes. However, that result may not be particularly instructive in predicting the outcome of Amendment One this year. The 1999 vote took place during a special election in June of an odd-numbered year, rather than a November general election. Only about 400,000 Iowans participated, compared to the more than one million voters who weighed in on constitutional amendments during recent general elections.
The Final Decision Rests with Iowans
On November 3, Iowans will decide whether to add another taxpayer protection to their Constitution by requiring a two-thirds legislative vote to increase income tax rates. Iowans who want to make their voices heard will need to turn over their ballots and find the question identified as Statewide Public Measure 1. Understanding the process that brought Amendment One to the ballot helps explain why constitutional changes are relatively rare in Iowa and why the final decision belongs to the people.