Will Democrats keep the Senate?
A briefing and forecast from Nonrival.
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This week’s forecast: Will Democrats keep the Senate (50 seats or more) in the midterm elections?
Make your own prediction:
Table of contents
Background
The US midterm elections on Nov. 8 will determine the composition of Congress for the next two years. The Senate is currently split 50-50, with vice president Kamala Harris providing Democrats the tie-breaking vote. 35 Senate seats are on the ballot—if Republicans pick up even one seat, they’ll hold the majority. (Republicans are favored to win a majority in the House.)
The president’s party almost always loses seats in the midterms. “Since the end of World War II, the president’s party has lost House seats in all but two midterms,” per Fivethirtyeight. But “the pattern is a bit more inconsistent in the Senate. Since World War II, the president’s party has either gained seats on net or at least avoided losing ground in six out of 19 midterms.”
Polls tilted toward Democrats over the summer, but that trend is fading. The Supreme Court's abortion decision and falling gas prices have been cited as explanations for Democrats’ polling surge; concern over inflation and a cooling economy could explain Republicans’ fall resurgence.
Polls are imperfect and in 2016 and 2020 they overestimated Democrats’ chances. For more on the ins-and-outs read Nate Cohn and Nate Silver.
Senate control will likely come down to close races in Georgia, Pennsylvania, Arizona, Nevada, and Wisconsin. Republicans have put forward several inexperienced, scandal-ridden candidates like Herschel Walker.
Perspectives
“In four of the most crucial races on the Senate map—Georgia, Arizona, Pennsylvania and Ohio—quirky political newcomers blessed by Trump are underperforming. The combined picture has many Republicans privately grousing that the former President may cost them the majority despite otherwise favorable conditions—again.” —Molly Ball, Time
“Republicans could have put themselves in a much better position to win in Georgia, Arizona, and Pennsylvania just by nominating real professional politicians… But despite it all, I think Republicans are going to take the Senate.” —Matt Yglesias, Slow Boring
“If you’d asked me a month ago — or really even a week ago — which party’s position I’d rather be in, I would have said the Democrats. Now, I honestly don’t know.” —Nate Silver, Fivethirtyeight
“We continue to rate Senate control a toss-up… Republicans still win voters who prioritize the economy but haven't been able to grow their share of them. Meanwhile the Democrats have not been able to grow the number of people prioritizing the abortion — an issue that favors them.” —Kabir Khanna, CBS News (part 1, part 2)
Forecasts
The Nonrival reader forecast:
Here’s a sampling of Nonrival readers’ reasoning…
Readers' reasoning
How likely is it (0-100% chance) that Democrats keep the Senate?
The case for Republicans taking the Senate:
18%: Boebert and [Marjorie Taylor Green] got in, a Walker is just as possible but Dr Oz will get in. Dems have a slim Senate majority and the MAGA crowd will bring a red wave to the House and will likely get the Senate too due to economy being a top issue.
33%: Historical losses with new President are tough to overcome. Poor economic outlook will make it easier for Republican candidates to win votes on “change” rhetoric
35%: I suspect that polling adjustments have still consistently undercounted republican support in a few districts.
The toss-up case:
45%: I watched enough of the Fetterman-Oz debate to think Fetterman will lose, fair or not. That's enough to throw everything in doubt.
50%: I don't really trust polls much anymore - I just don't think that pollsters have adjusted their methodology enough since their failures of the past 6 years. I think it's likely Fetterman and Warnock will win. N.B. I am often wrong about politics.
The case for Democrats:
65%: This is the first national election since January 6th. A significant number of voters will turn to Democrats because of that event.
70%: Issue salience around abortion (the inverse of suburban female voters breaking for Youngkin over schools) + lower than expected energy costs
Other forecasts
A roundup of forecasts from around the internet as of Oct. 30:
And here is Manifold Markets’ forecast: