Democrats are terrified of what the future holds for them in the United States Senate.
The party currently controls half the seats in the chamber, giving them, with Vice President Harris’s tie-breaking vote, the narrowest possible majority. But some in the party — like pollster David Shor, recently profiled by Ezra Klein in the New York Times — believe demographic trends put Democrats at grave risk of falling into a deep hole over the next two election cycles.
That risk exists even if Democrats continue to win more votes nationwide. “If 2024 is simply a normal year, in which Democrats win 51 percent of the two-party vote, Shor’s model projects a seven-seat loss, compared with where they are now,” Klein writes.
In other words, Republicans could well get a 57 to 43 Senate majority, the GOP’s biggest in about a century, even if Democrats win more votes.
This sense of impending Senate doom is the backdrop for many of Democrats’ debates right now — the messaging fight over whether the party should embrace “popularism,” the legislative fight over the reconciliation package that may be Democrats’ last chance to legislate for some time, and the frustration with a conservative Supreme Court majority that looks likely to be entrenched for years to come.
Democrats’ main problem is that they’ve been doing poorly among white voters without a college education, who are spread out across many states, while Democrats’ voters are concentrated in fewer, bigger states. (This is why Shor has been arguing that the party needs to change its message to better appeal to such voters.)
Recent presidential election results show how Democrats’ votes are packed into fewer states. When Biden won about 52 percent of the two-party popular vote in 2020, he won 25 states. But when Trump won about 49 percent of the two-party popular vote in 2016, he won 30 states. (If GOP Senate candidates had managed to replicate Trump’s map in 2018 and 2020, they would have won a 60-vote supermajority.)
Democratic presidential candidates’ struggle to win more states isn’t entirely new — George W. Bush won less than 50 percent of the national vote in 2000 but still won 30 states. What was different back then was voters were much more willing to split their tickets, voting for a presidential candidate from one party and a Senate candidate from the other. Ten states split their results like that in 2000 but zero did in 2016 and only one (Maine) did in 2020. The increased polarization and nationalization of politics are producing more uniform results.
To get a better sense of this, though, it’s worth delving into the specific seats that are in play. There are three Democrats representing states Trump won in 2020, all of whom are up in 2024. But there’s a second tier of vulnerability in the 10 Democrats representing states Biden just narrowly won. There are fewer Republican senators in comparable positions, and those that do exist seem to be on safer ground than their Democratic counterparts.
The mismatched senators
After the bitterly fought 2000 election, 30 of the 100 senators represented states that their party’s presidential nominee did not win. Since then, that number has gradually dwindled, as red-state Democrats and blue-state Republicans have retired or gone down to defeat. When Trump took office, there were 14 such senators remaining. Now, there are only six. The Senate has sorted by partisanship.
So to understand the map going forward, it’s useful to start with those six “mismatched” senators. There are three from each party, but that seeming parity is a bit misleading.
Two of the Republicans, Sen. Ron Johnson (R-WI) and retiring Sen. Pat Toomey (R-PA), represent genuine swing states that went narrowly for Trump in 2016 and narrowly for Biden in 2020. Both of these seats are on the ballot in 2022 and represent promising opportunities for Democrats if the party can avoid a midterm slump. Regardless, these seats will probably stay competitive in the future if these states remain competitive on a presidential level.
The third mismatched Republican, Sen. Susan Collins represents a bluer but not always overwhelmingly blue state (Biden won it by 9 points, Hillary Clinton lost it by 3 points). Collins won convincingly last year, becoming 2020’s sole split-ticket Senate victor, and isn’t up again until 2026.
The three mismatched Democrats, meanwhile, all represent states Trump won solidly both times. Sen. Sherrod Brown (D-OH) might be compared to Collins (Trump won Ohio by 8), but Sens. Joe Manchin (D-WV) and Jon Tester (D-MT) represent much more deeply red states than Johnson and Toomey (Trump won West Virginia by 39 and Montana by 16).
All three of these Democrats survived the Trump midterms of 2018, even as several of their red-state Democratic colleagues went down to defeat amid a strong year for Democrats nationally. But these seats will next be on the ballot in 2024, a presidential year. To survive, they’ll likely have to count on split-ticket voters. That was a plausible path to victory during the Obama years and before, but in the two presidential cycles since, only one senator, Collins, has managed to pull this off.
The overall takeaway is that the three Trump state Democrats will all start their 2024 races as deep underdogs (if they run again). Meanwhile, one Biden-state Republican is safe until 2026. The other two seats face some danger in 2022, but their states are inherently closer and they could be aided by the traditional midterm backlash against the president’s party, if that materializes.
That adds up to unfavorable math for Democrats. But it’s not their only problem.
The close states
The next tier of vulnerable senators represents states that their own presidential candidate just narrowly won. If we define a narrow win as “less than 3 percentage points,” there are 10 such Democrats: Sens. Raphael Warnock (D-GA), Jon Ossoff (D-GA), Mark Kelly (D-AZ), Kyrsten Sinema (D-AZ), Tammy Baldwin (D-WI), Bob Casey (D-PA), Catherine Cortez Masto (D-NV), Jacky Rosen (D-NV), Debbie Stabenow (D-MI), and Gary Peters (D-MI).
There are only two such Republicans: Sens. Richard Burr (R-NC) and Thom Tillis (R-NC). Expanding the definition slightly, to a 3.5 percentage point win, would also bring in Marco Rubio (R-FL) and Rick Scott (R-FL).
That’s a very big discrepancy. A slight shift in the national winds — a relatively minor deterioration of Biden’s and Democrats’ position — could knock out a whole lot of Senate Democrats. A similarly sized improvement of Democrats’ position doesn’t have the same upside because there aren’t as many Republicans representing close states.
It’s also useful to break these down by cycle. In 2022, Kelly (Arizona), Warnock (Georgia), and Cortez Masto (Nevada) are up for Democrats; Rubio (Florida) and the retiring Burr (North Carolina) for Republicans, plus Johnson and Toomey, Republicans in states that Biden won. That’s a relatively balanced map, meaning that Democrats’ biggest problem will be defying historical trends that the president’s party tends to lose voter support in the midterms. A bigger shift, or unique circumstances specific to the candidates, could also put other races in play.
But 2024 could be an utter debacle for Democrats in the Senate if the election goes poorly for them. Sinema, Baldwin, Casey, Rosen, and Stabenow are all up, along with the Trump-state Democrats Manchin, Tester, and Brown. Meanwhile, Rick Scott is the only Republican in a close state up that year.
Coalitions shift over time, and future elections could bring demographic changes few are yet anticipating. And none of this makes Democrats’ defeat inevitable. The Senate map for them looked rough on paper in 2012, but they walked away from that presidential year netting two seats.
But the structural disadvantage appears deep and real — it means Democrats, with their current coalition, have to clear a higher bar to win even a small majority. It also means the bottom can fall out quite quickly for them.