Polls point to Democratic House win, but Senate control remains a coin flip

The final days of the midterm cycle have settled on a clear trajectory for the House, but the Senate race remains shrouded in statistical uncertainty.

Recent surveys indicate Democrats are poised to capture the House, with an 8-point lead on the generic congressional ballot. This margin mirrors the 2018 cycle, which produced a substantial Democratic gain of 41 seats. President Trump’s approval rating, averaging 38% in recent polls, sits near the lowest point of his career and is 7 points below his standing before the 2018 election. The Cook Political Report now rates Democrats as favored in 220 House seats, projecting they will flip between 12 and 22 seats.

The path to the Senate is more complicated. Democrats need a net gain of four seats to take control. They are tied or leading in eight Republican-held seats: South Carolina, Alaska, Maine, Kansas, Texas, Iowa, Ohio, and North Carolina. They also have a chance in Michigan, held by a retiring Democrat. However, with the exception of North Carolina, all of these races are within the margin of error.

Historical data offers conflicting signals for these tight contests. In presidential elections, polls have recently understated Republican support by an average of 3.8 points, according to Nate Silver. That gap could be enough to flip most of the close Senate races back to the GOP. In midterm elections, however, the trend has reversed. Since 2016, polls have slightly overstated Republican support. Patrick Ruffini, a Republican pollster, notes that from 2018 to 2024, polls at this stage of the cycle overestimated Democrats by 6.2 points in key states like Iowa, Michigan, and Ohio.

Undecided voters present another variable. CNN polling found that in Texas and Kansas, at least 6 in 10 undecideds lean Republican. If political gravity favors the GOP, Democratic hopes for the Senate will face a headwind. Early voting data provides a clearer picture than polls. As of Thursday, 42 million early ballots have been cast, a number similar to the 2022 pace. Democrats account for 44% of the early vote, Republicans for 31%, and Independents for 25%.

In specific battlegrounds, the partisan split of early voters varies widely. In Maine, Democrats outnumber Republicans in early ballots by more than 2 to 1. In Iowa, the split is 48% to 33% for Democrats. In Kansas, the race is tighter, with Democrats at 45% and Republicans at 41%. In Michigan, a critical race for El-Sayed, voters under 40 make up only 14% of the early vote. That number is roughly half of what polls estimate. Republican candidate Mike Rogers leads among voters over 45, holding a 55% to 43% advantage in polls. If younger voters do not turn out in high numbers, Rogers has a stronger position than current models suggest.

The data favors Democrats for the House, but the Senate outcome hinges on the magnitude of the win. Republicans hold a cash advantage and a highly effective ground game, while Democrats rely on a clear directional lead in polling. The final result will depend on whether undecided voters in red states break for the GOP or if the early voting trends hold steady.