As of October 2024, Democrats have a 51-49 edge in the U.S. Senate, counting the 4 nominally “independent” senators who caucus with them.
They are Joe Manchin (WV), Kyrsten Sinema (AZ), Bernie Sanders (VT), and Angus King (ME), of whom Sanders and King are reliable Democratic votes, and Machin and Sinema somewhat less so.
All four have terms expiring in 2024, but neither Manchin nor Sinema are seeking re-election, while Sanders and King are shoe-ins for re-election. It’s certain Democrats will lose Manchin’s seat, but they’ll keep the Arizona seat.
If no other Senate seats flipped in 2024, the Democrats would have a 51-50 majority, provided there’s a Democratic vice president to provide the tie-breaking vote; otherwise, Republicans would control the chamber.
But Manchin’s seat isn’t the only Democratic-held Senate seat likely to change hands. In Montana, where Democratic Sen. Jon Tester faces a stiff but not hopeless challenge in a red state that Trump won by 16 points in 2020. Realistically, Montana probably will flip to the Republicans.
Political pundits are also watching Wisconsin and Ohio, but Democratic incumbents lead the polls in those states by what look like safe margins.
Assuming Republicans the West Virginia and Montana seats, and no others flip, they’ll have a Senate majority even if Democrats win the White House. These seems like the likeliest outcome. But three other Senate races, all involving Republican incumbents, could produce surprises. They’re in Florida, Texas, and Nebraska.
All of these races are fairly close. In Nebraska, an independent candidate could upset Sen. Debbie Fisher; Republicans are worried enough they’re spending money on that race (see story here).
In Texas, highly unpopular Sen. Ted Cruz (R) faces a serious challenge from Rep. Colin Allred (D); but Democratic efforts to defeat Cruz have failed before, and that’s the most likely outcome this time, too.
In Florida, Sen. Rick Scott (R) is a close race with former Rep. Debbie Mucarsel-Powell (D), but Florida like Texas is a red state, and that’s probably enough to save Scott’s seat for the Republicans.
All the conventional wisdom, punditry, and polling suggests the GOP will gain 2 Senate seats in this election cycle, just enough to give them a majority even if Harris wins the presidency, which could keep her from appointing cabinet secretaries and judges. Her transition team is making contingency plans to keep Biden’s cabinet members, who don’t have to be reconfirmed.
Other appointments, notably of judges, might have to wait on the results of the 2026 elections, but midterm elections typically don’t favor the party holding the White House. If Trump wins the White House and his party has even a narrow Senate majority, the Democrats’ ability to block extreme GOP legislation would rest upon retaking a House majority, where their chances are better than in the Senate.