Democrats’ Midterm Polling Advantage Explodes

Democrats have significantly expanded their midterm advantage over the past few weeks, widening their lead in the Generic Congressional Ballot and improving their position in key Senate races. What was already a favorable environment for Democrats at the start of September has moved even further in their direction.

On Sept. 1, Democrats held a 5.7-point lead in the RealClearPolitics Polling Average for the Generic Congressional Ballot. In the latest RCP Average, they lead by 8.7 points. That is larger than the lead held by either Democrats or Republicans at this point in any midterm election since 2010, even surpassing 2018, when Democrats led by 8.3 points at this point and went on to gain 41 House seats. To win back the House, Democrats only need to win a net of 3 more House seats.

The dramatic shift over the last few weeks comes down to a few factors. After Labor Day, some pollsters, such as Morning Consult, have moved from polling registered voters to likely voters. That change shifted its results slightly, with Democrats moving from a 4-point lead in its Aug. 31-Sept. 6 registered-voter poll to a 6-point lead in its most recent survey, conducted Sept. 11-13 among likely voters.

That means more pollsters are now accounting for who is actually likely to cast a ballot. Because midterms often favor the party out of power as its voters become more motivated to turn out, an increase in likely-voter polls could contribute to a larger Democratic lead in polls.

Another factor is the recent rise in oil prices, which have climbed again after falling earlier in the summer and declining further in early to mid-August. Brent crude stood at about $70 a barrel before Operation Epic Fury began in February, peaked at roughly $114 in May, fell to $72 in July, and has since risen to around $103. The increase has pushed the national average gas price to $4.43 per gallon, according to AAA, up from $3.20 a year ago.

Higher energy prices have also contributed to elevated inflation, which stood at 3.4% in August, according to the Consumer Price Index, well above the Federal Reserve’s 2% target. Elevated inflation prompted the Federal Reserve to raise the federal funds rate, and in turn other interest rates, on Wednesday for the first time since the summer of 2023.

The increased Democratic polling lead has also affected the party’s standing in the Senate. On Sept. 1, Democrats and Republicans were effectively tied in Polymarket’s betting markets, with each at a 50% chance of controlling the Senate after the midterms. Since then, Democrats’ chance of taking control of the Senate has risen to 60%.

Democratic advantages in individual swing states have also helped improve the party’s Senate outlook. In the eight states currently considered “Toss Ups” on the RCP Senate map, Democrats lead in the polls in all but one, Iowa. In other toss-up states, including states Trump carried by 10 or more points in 2024, such as Texas and Ohio, Democratic candidates currently lead in the polls.

If the candidate leading in the current RCP Average in every Senate race were to win, Democrats would finish with 52 seats, enough for a majority. Polymarket’s individual Senate markets currently point to the same 52-seat outcome.

The margins in many of these races remain extremely tight, however. In four races, the Democratic candidate’s polling lead is 2 points or less, well within the margin of error of any individual poll. If pollsters are even slightly overestimating Democratic turnout, or if political conditions shift in Republicans’ favor before Nov. 3, the outlook in several of these races could change quickly.