Zimmer narrowly leads in Iowa SD-35

Chaz Nuttycombe on crossover voting

Zimmer is winning Trump voters at the same rate as Sand.

Mike Zimmer leads Joe Stutting by 3 points with leaners (46% to 43%), just behind Rob Sand's 5-point lead over Zach Lahn in the Governor's race (47% to 42%). A big reason Zimmer is keeping pace with the top of the ticket is crossover support: among voters who say they voted for Donald Trump in 2024*, Zimmer wins 8%, the same share Sand gets, while Stutting wins just 2% of voters who say they voted for Kamala Harris. Ticket-splitting between the Governor and State Senate races is rare in both directions: about 1.5% of likely voters back both Sand and Stutting, and fewer than 1% back both Lahn and Zimmer. Most of the remaining gap between Zimmer and Sand comes from Sand voters who are still undecided in the State Senate race, about 2% of likely voters; if they come home, Zimmer should run right alongside Sand's margin. *As Mary notes below, there are probably a significant number of respondents who voted for Trump in 2024 but aren't telling us they did, so these crossover figures describe self-reported Trump voters rather than every likely Trump 2024 voter in our survey.

State Navigate Iowa SD-35 standard poll, PDF page 9.

Mary Radcliffe on the 2024 recall vote

Voters' memories of 2024 don't match the results, and Republicans are the reason.

Donald Trump carried SD-35 by 21 points in 2024, 60% to 39%, but our likely voters recall a much closer race: 48% say they voted for Trump and 41% for Kamala Harris. The gap comes from respondents who aren't reporting their 2024 vote accurately. Only 85% of registered Republicans in our survey say they voted for Trump, even after a follow-up question for those who initially declined to answer, while 90% of registered Democrats say they voted for Harris and 5% say they voted for Trump. The Democratic numbers look about right, but the Republican number isn't plausible: far more than 85% of this district's registered Republicans voted for Trump. The Republicans who don't report a Trump vote stand out in other ways, too: about two-thirds strongly disapprove of the job Trump is doing, and they favor Zimmer over Stutting 44% to 26% (a small group, so treat that split with caution). They look like Republicans who have soured on Trump and are reluctant to say they voted for him. Because of this, we did not weight this version of our results to recalled 2024 vote, and comparisons between this year's candidates and recalled Trump or Harris support should be read with caution. We are also releasing a companion version that weights recalled vote within each part of the district; it shows Stutting narrowly ahead, 47% to 45%.

State Navigate Iowa SD-35 standard poll, PDF page 9.

Chaz Nuttycombe on rural Republicans

A Canary in the Corn Fields: Rural Republicans in Iowa are difficult to reach.

In this version of our poll, which isn't weighted to recalled 2024 vote, the rural part of SD-35 looks far more Democratic than it should. Donald Trump carried the district's rural precincts by 37 points in 2024, but our rural respondents recall backing Trump by just 10 points; the State Senate race there is a dead heat, with Zimmer at 46% and Stutting at 45%, Sand leads Lahn 46% to 44%, and our rural respondents recall backing Trump by just 10 points. That points to a non-response bias amongst rural Republicans in Iowa. Our sample in DeWitt also looks too Democratic: Trump carried DeWitt by 18 points in 2024, but respondents there recall voting for Kamala Harris over Trump 51% to 43%, and Zimmer leads by 22 points. Clinton and Camanche, the most Democratic-leaning part of the district, are the exception: respondents there recall backing Trump by 8 points, 48% to 40%, almost exactly his actual 8-point margin in those precincts in 2024 (53% to 45%), and the State Senate race there is tied. That makes the gaps elsewhere stand out. Overall, this version recalls Trump winning the district by just 7 points, compared to his actual 21-point margin, so its district-wide result may still understate Republicans, even accounting for the respondents in our sample whom we believe are lying Trump voters. Our companion version corrects for this by weighting recalled vote within each region.

Reaching rural Republicans is a challenge for every pollster in Iowa. Ann Selzer's final Iowa Poll before the 2024 election showed Kamala Harris leading Trump by 3 points; Trump won the state by 13, and Selzer's post-election review pointed to Democrats becoming more willing than Republicans to take part in polls. This year, the statewide polling average has Rob Sand leading Zach Lahn by about 9 points in a state Trump carried by 13. It's worth asking whether statewide pollsters are running into the same problem we see in SD-35's rural areas, as Echelon Insights’ Patrick Ruffini noted on X/Twitter.

State Navigate Iowa SD-35 standard poll, PDF page 10.