As someone who stares at polls constantly, I’ve been a bit startled by a sudden recent trend, which I explained at New York:
While there are plenty of race ratings and election forecasts weighing the odds of a Democratic takeover of the U.S. House of Representatives in November, the single most reliable indicator historically has been the so-called generic congressional ballot, a poll question asking voters which party they want to control the House. It has probably become a bit more reliable of late given the steady rise of straight-ticket voting. And right now, the generic ballot numbers are spiking for the Democratic Party.
At the beginning of September, the very straightforward polling averages at RealClearPolitics gave Democrats a 5.7 percent margin in the generic ballot. As of September 17, the advantage has grown to 8.7 percent. In the more complex Silver Bulletin averages, in which polls are adjusted for partisan bias and weighted for accuracy and recency, the Democratic margin on the congressional ballot is 7.8 percent, a number that rises to 8.2 percent among likely voters. Both these numbers are the highest we’ve seen this calendar year. At DDHQ, which often leans more Republican in its findings, the Democratic generic-ballot margin is currently 7.7 percent.
In all these averages, a couple of especially high-quality polls have helped drive the Democratic spike. This week, a New York Times–Siena survey (the first since January) gave Democrats a 7 percent lead (49 percent to 42 percent) among registered voters and an 8 percent lead (51 percent to 43 percent) among likely voters. The cross-tabs in the “likely voters” version of the survey showed several especially notable advantages for Democrats: 68 percent to 25 percent among Hispanics; 57 percent to 34 percent among self-identified independents; and 64 percent to 29 percent among under-30 voters. These are all categories in which Republicans made crucial gains in 2024. The same poll gave Donald Trump a job-approval ratio among likely voters of 38 percent approval and 58 percent disapproval.
Margins aside, it’s very interesting that Democrats are doing better among likely voters than registered voters. This is most definitely a departure from the historical pattern in which the more likely voters have usually leaned Republican, particularly in relatively low-turnout midterm elections. This role reversal probably reflects two overlapping factors: the increasingly high education levels of voters in the Democratic coalition and sheer enthusiasm about the election. It also helps explain why Republicans this year have focused more on base mobilization tactics than on swing-voter persuasion. At this point in the election cycle, the GOP may be quietly conceding some of the more competitive contests and simply trying to avoid the kind of real disaster that could develop if red-state Republicans don’t show up at the polls.
There’s no exact correlation between generic-ballot showings and net House seats gained or lost. While the generic ballot is pretty good at estimating the national House popular vote, how this translates into seats won or lost enormously depends on the preelection landscape. In the last midterm election (2022), the final RCP averages estimated a Republican advantage of 2.5 percent. The actual margin was 2.8 percent, producing GOP gains of nine seats (enough to flip control of the House). In the 2018 midterms, the final RCP averages gave Democrats an advantage of 7.3 percent; they actually won the House national popular vote by 8.4 percent and made a net gain of 41 seats (flipping control of the House).
But while the current Democratic margin in the generic ballot is much closer to the 2018 numbers than to the 2022 advantage for Republicans, nobody is expecting anything like 41-seat gains because there are fewer vulnerable House Republicans this year. The consensus House forecast calculated by the 270toWin website shows Democrats gaining 20 seats if they win every single toss-up race. The Kalshi prediction market currently projects a net gain of 16 seats for Democrats. While not a 2018-style landslide, that would be more than enough to win the House and bust up the GOP trifecta no matter what happens in Senate races.
