Democrats eyeing a Senate takeover may want to hold the champagne.

CNN chief data analyst Harry Enten warned Wednesday that Republicans have repeatedly beaten their September polling in Ohio, Iowa and Michigan by margins large enough to erase the Democratic leads he highlighted in this year’s races.

Appearing on “CNN News Central,” Enten pointed to a familiar problem for Democrats heading into November: Encouraging polls haven’t always translated into votes.

“And, you know, fool me once, shame on you. Fool me four times, I just have to ask the question, could it happen again?”

In major 2024 races, Republicans outperformed September polls by 9 percentage points in Iowa, 6 in Ohio and 5 in Michigan.

The pattern also showed up with President Donald Trump off the ballot. During the 2018 midterms, Republicans exceeded September polling in major statewide races by 6 points in Iowa, 6 in Ohio and 8 in Michigan.

WATCH:

CNN: Republicans always outperform their September Rust belt/midwest polling

2024 Outperformance:
Iowa: 🔴 R+9
Ohio: 🔴 R+6
Michigan: 🔴 R+5

2018 Outperformance:
Iowa: 🔴 R+6
Ohio: 🔴 R+6
Michigan: 🔴 R+8

“Whether it be 2016, 2018, 2020, 2024 … Republicans have… pic.twitter.com/2YPcSqaajr

— OSZ (@OpenSourceZone) October 1, 2026

Another such performance could have major consequences. Enten outlined a scenario in which Republican victories in those three states produce a 50-50 Senate, even with Democrats winning Texas, Georgia, North Carolina and Alaska.

Vice President JD Vance would give Republicans control with his tie-breaking vote.

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