ID · Senate 2026 · Updated Oct 28, 2026, 2:01 a.m. ET
Idaho
Rated Likely R
Jim Risch wins this seat in 94 in 100 simulations. Call it all but certain.
Jim RischRIncumbent94 in 100
Todd AchillesI6 in 100
Over time
How the forecast has moved
The margin
How close it lands
Each simulation produces a final margin. The curve shows where those margins fall; the tinted areas on either side of even are the futures each party wins.
Under the hood
What's driving the number
The forecast blends a weighted poll average with a fundamentals model: the state's partisan lean, incumbency, the national environment, and fundraising. Positive points favor the Democratic side of the margin; negative favor the Republican side.
- Partisan leanR +17.5
- IncumbencyR +2.5
- National environmentD +4.7
- FundraisingR +0.6
- Fundamentals sayR +16.0
- The polls sayR +8.8
- Blended forecast marginR +12.4
The blend puts 50 percent of its weight on the polls and 50 percent on the fundamentals; polls take over as more arrive and election day nears.
The field
How other forecasters see this race
Ours isn't the only model on this race. Where another forecaster publishes a number — or we've copied one in by hand from a paywalled model — it appears here beside ours, dated, because models update on their own schedules. Forecasts disagree for knowable reasons: different poll filters, different weights on the fundamentals, different priors.
- Jim Risch winsThis forecast94 in 100
- Jim Risch winsRametta & Hare · as of Oct 27>99 in 100
No model is "right" before the votes are counted. How our number is made — and how it scored against 2012–2024 races — is on the methodology page.
The markets
What the betting markets say
Prediction markets put a price on this seat too: what people are paying for a contract that pays out if Jim Risch wins, read as an implied probability. Shown for comparison only. This is not betting advice, and market prices never feed the model.
- Jim Risch winsThis forecast94 in 100
- Jim Risch winsKalshi95 in 100
- Jim Risch winsPolymarket96 in 100
Market prices as of Oct 28, 2026, 2:00 a.m. ET
The evidence
The polls, as the model sees them
Every public poll of this race, with the weight the model gave it in the latest run. Weights reward recency, sample size, and pollster track record; the house adjustment corrects each pollster's habitual lean before averaging.
| Poll | Dates | Sample | D–R | Margin | House adj. | Weight |
|---|---|---|---|---|---|---|
| VoteNexus Research | Oct 21–22 | 700 LV | 43–49 | R +6.0 | — | 79% |
| Peak Insights (R) | Sep 28–30 | 500 LV | 24–49 | R +25.0 | — | 14% |
| Advanced Targeting Research | Sep 13–16 | 700 RV | 46–39 | D +7.0 | — | 5% |
| The Bullfinch Group | Aug 16–19 | 608 LV | 38–33 | D +5.0 | — | <1% |
| Peak Insights (R) | Aug 11–13 | 500 LV | 18–52 | R +34.0 | — | <1% |
| The Bullfinch Group | Aug 4–7 | 608 LV | 30–34 | R +4.0 | — | <1% |
| Change Research (I) | Jul 28–30 | 1,213 LV | 19–43 | R +24.0 | — | <1% |
| Peak Insights (R) | Jun 6–7 | 500 LV | 7–55 | R +48.0 | — | <1% |
| The Bullfinch Group | May 29–Jun 1 | 774 RV | 36–40 | R +4.0 | — | <1% |
| Public Policy Polling (I) | Mar 16–17 | 639 RV | 34–48 | R +14.0 | — | <1% |
How the weights, the blend, and the simulation work is spelled out on the methodology page.