Which party will take the US Senate seat Joni Ernst is vacating in Iowa?

Joni Ernst is stepping away from the Senate, opening an Iowa seat for the first time in years. She announced on September 2, 2025, that she would not seek a third term, which sets up an open-seat general election on November 3, 2026, between Republican Ashley Hinson and Democrat Josh Turek.

On paper, this should still favor Republicans. Iowa has voted Republican by double digits in its recent Senate elections, Trump carried Iowa by 13.21 in 2024, and Republicans hold a sizable edge in registered voters.

The reason it is getting treated like a coin-flip anyway is that both polls released this month point the other way. Rasmussen, fielded September 8 to 10, put Turek up 5. YouGov, on September 8, put him up 1. PollingSource's average of the race now sits at R+0.3, which is basically a coin flip, and Cook Political Report moved it to Toss Up on August 20.

The strange fact is that prediction markets do not agree with the polling data. Kalshi prices a Republican hold at 61.5%, while the polling says something close to 50-50. This is because a poll asks people how they would vote today, while a market asks traders what will actually happen in seven weeks. Traders paying 61.5 cents are betting the race drifts back toward Iowa's habits before election day, the way Iowa races usually do.

Even accepting the polling case, you still have to face the obvious counterpoint, which is that Iowa polling has been wrong before, badly and recently:

• Ann Selzer's final Iowa Poll had Harris ahead by 3. Trump won the state by 13.21, a 16-point miss, and Selzer stopped polling elections afterward.
• Ernst against Theresa Greenfield polled as a toss-up for months. Ernst won by 6.59 points.

Still, despite Hinson raising $10.2m to Turek's $6.3m, there’s a small but very important caveat. Only 10% of Hinson's money comes from donors giving $200 or less, meaning roughly nine dollars in ten arrive from maxed-out donors, party committees, and PACs. For Turek, that small-donor share is 43%.

A 43% small-dollar share is really good, and it is. However, it is also quite similar to the last Democrat who tried this. In 2020, Theresa Greenfield outraised Ernst four to one and posted a record $28.7m quarter built on small online donations, much of it from outside the state. So, the support was coming not from Iowans, which logically ended with Greenfield’s loss. This time, though, the Republican has the larger war chest and the institutional money behind it.

So it comes down to one question: how much do you trust the polls? Iowa polling missed by 16 points in the last presidential cycle and called a toss-up that finished 6.59 points clear, while the state itself moved further Republican across those same two cycles, from 8.2 points in 2020 to 13.2 in 2024. We think a 0.3-point polling lead is not enough to outweigh that, especially with the money and the registration edge sitting on the same side. Which is why we are buying the Republican contract at 61.5 cents to capture 62.6%.