Our forecast gives Democrats a 66% chance of taking the Senate. That number assumes something we know isn't quite true: that the polls, on average, are right.
They usually aren't. So we built a way to see what happens when they're wrong.
Slide it yourself: members.rationalground.com/if-the-polls-are-wrong
How it works
Every animal on the boat is one Senate seat: donkeys for Democrats, elephants for Republicans, and moose for the independents (Angus King and Bernie Sanders, who vote with Democrats, and Nebraska's Dan Osborn, who has said he won't join either party's caucus). The 65 seats not on the ballot this year ride at the two ends.
Slide the polls toward one party and every race moves by that many points. When a race's likely winner changes, its animal flips, a buoy pops up with the state's name, and the boat leans toward the heavier side. The odds on the sail don't come from a shortcut. For every point of miss, we re-ran the forecast's 20,000 simulated elections with every margin moved by that much, and the slider blends between those runs.
The misses we've actually had
The notches on the slider are real. The American Association for Public Opinion Research (AAPOR) measured how far the final two weeks of polls missed, across all races:
2016: polls overstated Democrats by 3.1 points.
2018: by 0.1 points. Essentially right.
2020: by 4.6 points.
2022: they overstated Republicans by 0.6 points.
2024: they overstated Democrats by 2.7 points.
Here's what each would do to this year's Senate:
A 2018 miss: no seats flip. Democrats are 65% to take the Senate.
A 2022 miss: Nebraska, Kansas and Iowa flip. Democrats, 73%.
A 2024 miss: Alaska, Texas, Ohio, Maine and Michigan flip. Republicans are 67% to keep the Senate.
A 2016 miss: the same five flip. Republicans, 72%.
A 2020 miss: the same five flip. Republicans, 86%.
The tipping point is small. A miss of just 1.3 points toward Republicans makes them the favorites.
The pattern worth watching
Look at the years. The big misses, all toward Democrats, came in 2016, 2020 and 2024: presidential years, with Donald Trump on the ballot. In the two midterms in between, the polls were nearly dead on.
2026 is a midterm. If this year's polls behave like 2018 and 2022, Democrats stay favored. If they behave like the presidential years, Republicans are favored to keep it. Nobody knows which kind of year this is. That's the honest answer, and it's why we built the slider instead of just giving you one number.
What it doesn't do
Real polling misses aren't tidy. In 2020 the polls missed more in some states than in others. The slider moves every race by the same amount, which is a simplification. Treat it as a way to see how fragile the Senate is, not as a prediction of where any one race lands.
And yes, it has sound. Tip the boat and the crowd on deck will tell you about it.
Try it: members.rationalground.com/if-the-polls-are-wrong
The full forecast, with every Senate, House and governor's race, is for members at members.rationalground.com/elections.
Forecast as of Oct. 22, 2026. Polling misses: AAPOR, Task Force on 2024 Pre-Election Polling, executive summary.