2026 ballot measure forecast

Iowa Amendment 1

Two-thirds legislative vote to raise income taxes

Requires a two-thirds vote of both chambers of the Iowa General Assembly to raise individual or corporate income tax rates or to create a new tax on income. The forecast has Yes at 53.9 percent against the 50 percent it needs, a 71% chance to pass.

Leans passConstitutional amendment referred by the legislatureIncome taxUpdated October 17, 2026

Chance to pass

71%

2,000 simulations

Forecast Yes

53.9%

80% range 45 to 63

Needs

50%

a simple majority

Polling average

43.4%

Yes, with undecided split two to one for No

County forecast

95 of 99 counties vote Yes

No +30Yes +30Hover a county for its forecast

Where the Yes vote lands

needs 50

2035506580

History and structure: 65.2% Yes
Polls: 43.4% Yes
Forecast: 53.9% Yes
Yes leans: Republican
Rule to pass: Simple majority of those voting on the amendment. Passed GA twice (HJR 2006 in 2024, SJR 11 in 2025-26) on party-line votes.

The campaign

Yes: Iowans for Tax Relief and GOP legislators. No: Fair Taxes for Iowa's Future coalition (Common Good Iowa, Iowa State Education Association, labor). No dollar figures reported.

Polls of the measure

1 poll

Pollster	Sample	Ended	Yes	No	Undecided	Yes, adjusted
Suffolk University Political Research Center	500 LV	2026-08-23	33	36	30	43.4%

How this is built

Amendment 1 is forecast as a income tax measure whose Yes vote leans Republican. Comparable measures from 2018 to 2024 set how far its Yes share moves with Iowa's partisanship and with each county's 2024 presidential vote, and how it reached the ballot moves it further. Polls then pull the forecast toward them by recency and size, after splitting undecided voters two to one for No. Sources: news.ballotpedia.org , iowacapitaldispatch.com , newsfromthestates.com , kcrg.com. All measures.