How Many House Seats Would Democrats Gain?

Nate Silver says a model with a 90% plus chance of Democrats winning the House still translates into only about 22 seats on average.

Redistricting and voter self-sorting left far fewer swing districts than before. Democrats also had a relatively good 2024 in the House, and on election night there was still doubt about Democrats winning the chamber despite Harris having lost. Wave elections have reached 40 or 50 seats, including 63 in 2010 and about 41 in 2018. Republicans gained a few seats from redistricting, mostly by cutting out a majority-minority district. Louisiana, Alabama, and Tennessee amount to a clean three seats wiped out for Democrats, though the Alabama district is kind of close in the polling. Texas and Florida are not showing many Republican gains. In Texas, the theory was that a firmer hold on lower-income Hispanic voters would allow more risks, and the polls show lower-income Hispanic voters shifting most aggressively back toward Democrats. In Florida, DeSantis drew a riskier map, optimized more for presidential years, with a lot of toss-up to lean districts in the present environment.

A likely House win is a much smaller shift than the 2010 or 2018 waves. Fewer swing districts, a relatively good 2024 in the House, and the three seats already removed from the maps keep the average gain near 22.