What If the Polls Are Underestimating the GOP?

Polls may underestimate GOP strength in 2026, favoring Republicans in Senate and House races.

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Last month, we reported that Democrats are once again convincing themselves that reliably red states are winnable in 2026, driven almost entirely by encouraging summer polling results. It is the same mistake the party has made cycle after cycle, and the historical record on this is not close. Polls in red states consistently overstate Democrat support during the summer months, and by the time Election Day comes, that support tends to evaporate.
Pollster Patrick Ruffini discovered this pattern and believes 2026 is shaping up to look identical to the cycles before it. Senate polling in red states has overstated Democrat support during the summer months in each of the last four election cycles, and the same trend is already showing up in this year's numbers.
To prove it, Ruffini pulled 3,312 polls from the last four election cycles out of the old FiveThirtyEight archive, and the results were remarkably consistent. Polls overstated the Democrat candidate's margin in every single cycle he examined, averaging a D+3.7 error, with 73% of polls overstating Democrat support.
The error is not static, though.
It peaks at 5.9 points too Democrat in late July, starts shrinking by late August, and settles at an average of D+2.6 by Election Day. That is still a real bias toward Democrats, but it is far smaller than the numbers Democrats and the media tout in July, when red states suddenly look competitive.
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This raises an obvious question. What would Election Day 2026 actually look like if that exact pattern repeats itself this year? CNN's chief data analyst Harry Enten decided to find out.
Enten modeled what the 2026 Senate map would look like if the polls are underestimating Republicans by two to four points, the same kind of miss Ruffini's data shows has happened before. Under that scenario, Republicans hold 53 Senate seats to the Democrats' 47.
North Carolina and Georgia remain blue, but…
Maine stays red.
Ohio stays red.
Iowa stays red.
Alaska stays red.
Michigan flips red.
And yes, Texas stays red.
"This polling error absolutely has happened before," Enten added.
The House picture is similar. If the polls undershoot Republicans by more than three points, "that's all you need" for the GOP to hold the U.S. House of Representatives, according to Enten, who put a Republican majority at 218 or more seats under that scenario. Enten pointed out that Republicans currently trail in the House generic ballot average, but that does not settle much on its own. "Even if Democrats are favored, it is still within the margin of error," Enten said.
Democrats will keep pointing to summer polling as proof that the map is expanding in their favor, and PJ Media will keep pointing to the historical record that, at the very least, suggests they could be wrong. If the polling error looks anything like it has in each of the last four election cycles, Republicans are on track to expand their Senate majority in November. This is not a reason to get complacent; it’s a reason to remain vigilant.