Senate / IllinoisIllinois Senate 2026 · seat held by Democrats (open seat)
Juliana Stratton is heavily favored to win Illinois
Juliana Stratton99%Democrat
Don Tracy1%Republican
Forecast marginD+17.780%: D+9.0 to D+26.0
Tipping point0.2%chance it decides control
Cook ratingSolid DOct 20
2024 presidentD+10.9nation R+1.5
Polls
Each dot is a poll after adjustment; grey ticks show where it was as publishedDot size shows the weight a poll gets. The line is the model's polling average, with its 80% band. The bar at right is the 80% range of the forecast on election day.
Range of outcomes
Democratic margin across simulationsJuliana Stratton wins in 99% of simulations (about 1 in 180 for the underdog). Median margin D+18.0.
Chance of winning over time
Daily reruns of the modelEach day is a fresh run of today's model using only the polls that had finished by the day before. Daily runs since Jul 1.
How the forecast is built
Fundamentals D+21.1. Illinois voted D+10.9 for president in 2024, 12.4 points more Democratic than the nation. Add the national generic-ballot margin (D+8.7).
Polls D+14.7. 2 polls, adjusted for house effects and likely-voter screens. Polls carry about 53% of the weight.
What this race means for control
Because polling errors are correlated, a win here usually comes with wins elsewhere.
Every poll in the model
| Pollster | Field end | Sample | Published | House effect | Adjusted | Weight |
|---|---|---|---|---|---|---|
| ActiVote | Oct 20 | 400 LV | D+17.0 | R+0.6 | D+17.6 | 0.27 |
| PPP D internal | Oct 1 | 569 LV | D+13.0 | D+0.2 | D+12.6 | 0.31 |