- Businessman Zach Lahn pulled off one of the biggest upsets of the 2026 cycle, defeating Trump-endorsed Rep. Randy Feenstra in Iowa’s Republican governor primary, 37.8% to 37%. Feenstra conceded Tuesday night.
- Democrat Rob Sand and Republican Zach Lahn will face off in November in a governor’s race Kalshi already had priced at 64% Democrat. Lahn’s surprise win could shift those odds.
- State Rep. Josh Turek won the Democratic Senate primary over state Sen. Zach Wahls and will face Republican Rep. Ashley Hinson in November. Kalshi had Republicans at 62% in that race.
- Three Iowa House races are set for November: IA-1 (Miller-Meeks vs. Bohannan rematch), IA-2 (open seat), and IA-3 (Nunn vs. Trone Garriott). All three are competitive.
- Iowa’s primary results set up one of the most loaded November election odds maps in the country, with five highly competitive races across the state.
DES MOINES, Iowa — Iowa’s June 2 primary delivered a genuine surprise. Businessman Zach Lahn defeated Trump-endorsed U.S. Rep. Randy Feenstra in the Republican governor’s primary by fewer than 1,000 votes.
It was one of the most unexpected results anywhere on the 2026 map so far. Feenstra had Trump’s endorsement, a massive fundraising advantage, and the backing of the Iowa Republican establishment. None of it was enough.
The upset matters for the election odds heading into November. And in the Senate, House, and remaining congressional races, Iowa is now set for what may be the most competitive statewide slate in the country.
Governor: Lahn Over Feenstra in a Stunner
With 99% of the vote in, Lahn took 37.8% compared to Feenstra’s 37%. Feenstra conceded Tuesday night.
In his victory speech, Lahn said his win was a message. He told supporters that Iowa “doesn’t belong to the political class” and that voters rejected the lobbyists and special interests who backed Feenstra.
Lahn, a farmer and businessman, ran as a supporter of the Make America Healthy Again movement and positioned himself as an outsider. His win came despite being outspent significantly by Feenstra, who had transferred money from his congressional PAC and secured Trump’s backing just one week before the election.
Before the primary, Kalshi gave Democrats a 64% chance of winning the governor’s race in November and Polymarket had it at 67%. Those numbers were built around Feenstra as the expected Republican nominee. Lahn’s win could shift those Gubernatorial odds — his lower name recognition and unproven general-election appeal may give traders reason to move the market.
Democrat Rob Sand, the state auditor, ran unopposed in his primary. He will be the clear general-election favorite until markets reprice around Lahn.
What the Lahn Win Means for Sand’s Odds
Heading in, traders liked Sand’s chances because Feenstra was a well-known, well-funded, Trump-aligned candidate who could consolidate the Republican base. Lahn is none of those things going into the general election.
Sand won reelection as state auditor in 2022 even as Republicans swept every other statewide office in Iowa. He is the lone Democrat in Iowa to hold office in a statewide elected position.
Trump won Iowa by about 13 points in 2024. That structural lean still favors Republicans. But Lahn’s outsider campaign and thin primary margin could make him a weaker general-election candidate than the markets had priced.
Senate: Turek Wins, Now Faces Hinson
State Rep. Josh Turek won the Democratic Senate primary over state Sen. Zach Wahls. Turek is a two-time Paralympic gold medalist in wheelchair basketball and a former U.S. Army veteran.
Before the primary, Kalshi gave Turek an 88% chance of winning the Democratic nomination over Wahls. He delivered on that price. He now faces Rep. Ashley Hinson, who won her Republican primary easily.
Kalshi and Polymarket both had Republicans at 62% to hold the Senate seat in November. Those Senate election odds are expected to hold roughly steady. Hinson was the expected nominee and came in as planned. The general election market will remain competitive.
House: Three Battlegrounds, All Set
In IA-1, Rep. Mariannette Miller-Meeks will face Democrat Christina Bohannan for the third straight time. Miller-Meeks beat Bohannan in 2024 by fewer than 800 votes. Cook Political Report rates the race a toss-up.
In IA-3, Rep. Zach Nunn runs unopposed in his primary and will face Democratic state Sen. Sarah Trone Garriott again in November. IA-1 and IA-3 are among the most competitive markets based on House of Representatives odds on Kalshi.
IA-2 is now an open seat after Hinson left to run for Senate. Former state Rep. Joe Mitchell won the Republican nomination. He will face Democratic state Rep. Lindsay James in November. That district voted for Trump in 2024 but could be competitive with an open seat.
The Bottom Line
Iowa’s primary delivered one big surprise and several expected outcomes. The governor’s race now has a different shape than prediction markets expected. Lahn is a weaker general-election candidate on paper, and Sand’s odds may improve once markets adjust.
The Senate race looks the same as it did yesterday. Turek was the expected Democratic nominee and he won. Hinson was the expected Republican nominee and she won. The 62-38 Republican edge on Kalshi should hold.
No state has five more competitive races heading into November than Iowa.
The election odds in Iowa across the governor, Senate, and three House contests make it the most loaded midterm battleground map in the country.
All Iowa general elections are set for November 3, 2026.
