Democrats Projected to Win 51 Senate Seats as Even GOP Strongholds Start to Wobble

Forecasts suggest Democrats could secure 51 Senate seats and potentially a House majority in the 2026 U.S. midterm elections. The polling analytics firm Signal Politics Institute (SPI) analyzed that voters' assessment of President Trump's governance is reshaping the balance of power in Congress. This election covers all 435 House seats and 35 Senate seats. SPI estimated each district's win probability by combining past election results, regional partisan leanings, incumbency advantages, presidential approval ratings, and candidate competitiveness.

Of the 36 competitive House districts, Republicans held the advantage in local support bases in 33, but the presidential and partisan approval effect favored Democrats. In 19 of those districts, this effect surpassed the Republicans' local advantage. In Iowa's 3rd Congressional District, which Trump won in the 2024 presidential election, Democrats' win probability was calculated at 59.6%. In Florida's 25th Congressional District, the Democratic candidate's win probability also came out at 60.9%.

The Senate currently comprises 53 Republicans and 47 Democrats and independents who caucus with them, meaning Democrats need to flip at least four seats to reach a majority. Most Republican seats up for election this cycle are concentrated in states Trump won in 2024.

In Texas, where Democrats have not won a Senate race since 1988, state Representative James Talarico is facing off against Republican state Attorney General Ken Paxton. Paxton, backed by Trump, defeated incumbent Senator John Cornyn to become the GOP nominee. In Alaska, Mary Peltola, who won a House seat as a Democrat in 2022, is challenging incumbent Republican Senator Dan Sullivan.

However, opinion polls repeatedly underestimated Trump's actual vote share in the 2016 and 2024 presidential elections. Whether the 'shy Trump voter' phenomenon will resurface in this election therefore remains a wildcard.