Final midterm projections give Democrats high odds to sweep Congress

( NewsNation ) — The polls on the East Coast are open, and with that comes the end of prediction season. Democrats are hoping they aren't being set up for another polling let-down.

Forecasting models and prediction markets have gone from guardedly optimistic to more confident that the Democrats will take the Senate as well as the House. Decision Desk HQ, which partners with NewsNation for race calls, gives them a 63% chance to control the House and Senate in 2027. They give Republicans a 15% chance to do the same.

DDHQ is more confident in the Democrats' chances of winning the House, which they predict will go blue to the tune of around 241 seats.

Republicans were projected to win the Senate as recently as Labor Day weekend, but the Democrats' odds in DDHQ's estimation have shot up in the last couple of months. They project the Democrats will win 52 seats — one more than they would need.

Prediction markets are even more bullish. Polymarket has the Democrats at a 75% chance to sweep, while Kalshi is a tick below that at 74%. Silver Bulletin , run by election modeler Nate Silver, puts Democrats' odds of a sweep at 82%.

A recent New York Times-Sienna poll paints a picture of a big night for Democrats, but we've seen this before, only for Democrats to underperform relative to those expectations. Presidential elections in 2016, 2020 and 2024 each saw Republican candidates underrepresented in polls by around 3-5%, according to Silver Bulletin. If you apply that error to many races in this election, the Democrats likely don't take the Senate and the House may be closer than everyone is expecting.

NewsNation provides comprehensive coverage of the 2026 midterm elections like never before, with live results powered by Decision Desk HQ and expert analysis. Stay tuned for race calls after the polls close Tuesday night.

But the story in midterm polls hasn't been as dramatic. In 2018 and 2022, the polling error in favor of Democrats was less than 1%, per Silver Bulletin.

Midterm elections 'toss up' races to watch

DDHQ lists eight Senate seats in "lean" or "toss up" categories: Kansas, Iowa, Ohio, Alaska, South Carolina, Texas, Maine and Nebraska. At the beginning of the year, Democratic wins in at least six of those states were borderline unthinkable. Maine has always represented hope for Democrats because it tends to vote blue, despite electing Sen. Susan Collins, a Republican, time after time.

Sherrod Brown, the Democratic candidate in Ohio, is nearly two years removed from serving in the Senate, so it would be less surprising to see him return than to see Kansas send its first Democratic senator to Washington since the 1930s.

Stick with NewsNation as results come in tonight. We will have special election coverage Tuesday night starting at 7p/6C with Chris Cuomo, Elizabeth Vargas, Leland Vittert, Katie Pavlich and Chris Stirewalt.