Democrats who have been telling their constituents the party is on the verge of a big blue wave during next month’s midterm elections are very likely overselling the expected results.
That’s according to CNN’s data guru, Harry Enten.
Enten warned on Friday that even a relatively ordinary polling error could completely reshape battles for the House and Senate.
Current Senate polling shows Democrats narrowly ahead in several of the races that could determine control of the chamber, but Enten emphasized that most of those advantages are smaller than the historical polling error in competitive Senate contests.
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During the segment, Enten pointed to polling averages showing Democrats ahead by four points in Ohio, three in Michigan and Texas, and two in Maine and one in Iowa, while Kansas was tied.
If those numbers precisely matched the November 3 results, Democrats would capture enough seats to take control of the Senate, where Republicans currently hold a 53-47 majority.
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But Enten said history provides an important reason for Democrats to remain cautious because final polling averages in close Senate races have missed the actual result by an average of approximately 3.7 percentage points.
Most of this year’s pivotal Senate races currently fall comfortably inside that historical error range, meaning small polling misses could produce substantially different results from those suggested by today’s averages.
Enten called that possibility a “big siren warning sign for Democrats,” particularly because Republicans have repeatedly performed better than polling suggested in several battleground states during recent elections.
To demonstrate the potential impact, Enten recalculated the Senate map under a scenario in which Republicans outperform current polling averages by 3.75 percentage points.
CNN: If the polls underestimate the Republicans by only 3 points they will win both the house and the senate
Senate:
🔴 Republicans: 53
🔵 Democrats: 47House:
🔴 Republicans: 218
🔵 Democrats: 217 https://t.co/YOPXebqXgt— OSZ (@OpenSourceZone) October 15, 2026
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Under that hypothetical, Republicans would finish with a 52-48 Senate majority and win closely contested races in Maine, Michigan, Texas, Kansas, Iowa and Alaska, according to Enten’s analysis.
He also said the same Republican polling overperformance would allow the GOP to maintain control of the House, where Republicans currently hold an extremely narrow 218-214 majority with two vacancies and one independent caucusing with the party.
Democrats need a net gain of four seats in both chambers to seize control, making even a handful of races potentially decisive in determining the balance of power in Washington.
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Enten raised a similar concern in September when examining recent polling errors in Iowa, Ohio and Michigan, three states where Democrats have posted encouraging numbers during the closing weeks of the campaign.
Republicans outperformed September polling by nine points in Iowa during major 2024 races, six points in Ohio and five points in Michigan, according to Enten’s analysis.
The phenomenon was not limited to presidential elections involving Donald Trump, as Enten noted that Republicans also exceeded September polling by six points in Iowa and Ohio and eight points in Michigan during the 2018 midterms.
Those historical misses do not mean Republicans will necessarily outperform the polls again in 2026, particularly because polling methods, electorates and individual races change from one election to another.
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Enten himself has repeatedly stressed that polls are tools rather than predictions and that being ahead remains preferable to being behind, while cautioning viewers against treating narrow polling advantages as guaranteed election results.
The warning is especially important in the Senate because several Democratic candidates are currently leading by margins smaller than the average historical polling error Enten identified.
The House presents a different picture, with Democrats generally performing more strongly in national generic-ballot polling, but the chamber’s razor-thin Republican majority means relatively small shifts across competitive districts could still determine control.
Reuters reported Monday that more than $3.8 billion in political advertising had already aired during the 2026 midterm cycle as both parties pour resources into congressional races, particularly Senate contests in Texas, Ohio and Michigan.
“The polling has been tight,” Enten said, concluding that the Senate remains too close to call and that Republicans are “very much in the ball game.”
This article may contain commentary which reflects the author’s opinion.
