Polls understated Democrat vote in landslide repudiation of Donald Trump

All 435 United States federal House of Representatives seats and 35 of the 100 Senate seats were up for election in yesterday’s midterm elections.

In the 2024 elections, Republicans won the

House by 220–215 over the Democrats and the Senate by 53–47. Due to Vice President JD Vance’s tie-breaking vote, Democrats needed at least a net four-seat gain to win control of the Senate.

Democrats have gained a total of seven Senate seats, with five of those gains coming in states Donald Trump won at the 2024 election by double-digit margins: Ohio, Kansas, Iowa, South Carolina and Texas. Democrats will have a 54–44 Senate majority, with two contests undecided: Alaska and Mississippi.

In Mississippi, Democrat Scott Colom has taken a 65-vote lead over Republican incumbent Cindy Hyde-Smith with over 95% counted. This may well take weeks to resolve.

In Alaska, Democrat Mary Peltola leads Republican incumbent Dan Sullivan by 48.2–47.9 with 77% counted. Alaska uses preferential voting, so votes from excluded candidates are transferred. This will favour Sullivan as one of the other candidates is a Republican.

But late counting in Alaska strongly favours Democrats, so I expect Peltola to extend her lead, and probably win a majority of the vote before preferences.

Democrats easily won the other two seats where they were favoured but with some doubt in my election preview, gaining Maine and holding Michigan. Democrats had been favoured to win all the seats they won except South Carolina.

In the House, Democrats lead Republicans by 237–147 in called seats with 51 seats still uncalled. Late counting usually favours Democrats, so they may expand that lead. US media don’t appear to track the House popular vote.

In the biggest shock yesterday, Democrat Annie Andrews gained the South Carolina Senate seat, defeating Republican incumbent Darline Graham by 51.1–46,7, a 4.4-point margin. Graham had been appointed to replace her brother, Lindsay Graham, who had died in July.

South Carolina voted for Trump by almost 18 points in the 2024 presidential election. Graham had led in pre-election polls by 1.3 points.

Democrats won the Kansas Senate for the first time since 1932. They won the Texas Senate for the first time since 1994. They won the South Carolina Senate for the first time since 1998.

Democrats are likely to win the House by the biggest Democratic margin since the 2008 election where Barack Obama was elected president.

This election was a massive repudiation of Trump, who has a net approval of -20.4 in Nate Silver’s aggregate, far worse than the next worst at this point in a presidency (Joe Biden at -11.2).

A month after the November 2024 presidential election where Trump defeated Democrat Kamala Harris by 1.5 points in the national popular vote, I wrote this was not a landslide and that Democrats had cause for optimism at these elections. In fact, they greatly exceeded my expectations in that article.

I also had live coverage of the midterm elections for The Poll Bludger.

Poll performance

In my election preview, I said if polls overstated Democrats by about four points, Republicans would probably hold the Senate. But polls actually understated Democrats, so they won by a greater than expected margin.

For example, polls gave Democrat James Talarico a 3.5-point lead over Republican Ken Paxton in the Texas senate contest, but Talarico actually won by 55.1–43.0, a 12.1-point margin.

There were some contests where Republicans overperformed their polls, but these came against independents, not Democrats. In Nebraska’s Senate contest, Republican incumbent Pete Ricketts defeated independent Dan Osborn by 50.4–43.6, a 6.8-point margin. Polls had only given Ricketts a 0.8-point lead.

Adrian Beaumont does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.