In a bit of electoral déjà vu, Democratic Sen. Raphael Warnock won Georgia’s runoff on Tuesday, almost two years after he won a special election runoff to help hand Democrats a narrow 50-50 majority in the Senate via Vice President Kamala Harris’s tie-breaking vote. This time around, Warnock topped Republican Herschel Walker to earn a full six-year term, which will have major ramifications for how the new Senate will conduct business in January. Warnock’s win gives Democrats 51 seats — including independent Sens. Angus King of Maine and Bernie Sanders of Vermont — so the Democratic caucus will no longer have to constantly rely on Harris to break ties. Democrats will also now have majorities on each committee and will be able to more easily confirm President Biden’s judicial appointments.
Yet if we look even further into the future, it turns out the Georgia outcome could also play a role in deciding which party controls the Senate after the next election. The good news for Democrats is that they will have 51 seats instead of 50, which gives them a chance to maintain control even if they lose one seat, depending on whether the next vice president is a Democrat or Republican. The good news for Republicans, however, is that the 2024 Senate map puts them in a better position to take control of the chamber than it does for Democrats to hold onto it.
Democrats have more than twice as many Senate seats to defend in 2024 as Republicans, an imbalance that gives the GOP a clear path to capturing the Senate — even if the Georgia result has given Democrats a little breathing room. At present, 34 Senate seats will be up for election,1 and of those, Democrats (including the independent senators who caucus with them) hold 23 to the GOP’s 11, as the table below shows.
|State||Current incumbent||Party||2020 Pres. Margin|
|PA||Bob Casey Jr.||D||D+1.2|
That Democrats have so many seats to defend in 2024 is a byproduct of past electoral success. Each class of Senate seats is up every six years,2 so the group of seats up in 2024 was previously up in 2018 and each six-year mark prior to that. In 1994, Republicans enjoyed a wave election in which they gained eight Senate seats. But ever since, Democrats have developed a sizable advantage among this batch of seats: In 2000, Democrats gained four seats amid a razor-tight presidential election; in 2006, they gained six seats thanks to a midterm Democratic wave;3 in 2012, Democrats gained two more thanks to upset wins in North Dakota and Indiana; and in 2018, they lost two net seats but managed to pick up a seat in increasingly competitive Arizona while avoiding more sizable losses by holding onto seats in Montana, Ohio and West Virginia.
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But as a result, Democrats now must defend the now red-leaning seats of Sens. Jon Tester of Montana, Sherrod Brown of Ohio and Joe Manchin of West Virginia. All three won reelection in 2018, but those elections took place in a heavily Democratic-leaning environment that they can’t count on having again in 2024. In addition to those three redder seats, Republicans will surely also target swing-state seats in Arizona, Michigan, Nevada, Pennsylvania and Wisconsin.
Though Republicans have ample pickup opportunities, Democrats can realistically hope to flip only two GOP-held seats in 2024: Florida and Texas. Still, given the strong Republican showings in Florida recently and the inability of Texas Democrats to break through statewide, even as the state has become a lighter shade of red, the GOP incumbents will likely start as favorites in these seats in a way that isn’t true for Brown, Manchin and Tester.
Looming over each of these Senate contests is the presidential race that will undoubtedly influence down-ballot outcomes. In recent years, the party that carries a state in the presidential contest has usually won its Senate race. In 2020, just one of 35 Senate races went for a different party from the one that carried the state in the presidential election (Maine), while in 2016 all 34 Senate elections went for the same party that carried the state at the presidential level, as the chart below shows.
In fact, in the next Congress, just five senators4 out of 100 will occupy seats in states that the other party’s presidential candidate carried in 2020 — and three of them are the red-state Democratic trio up in 2024. In other words, Republicans stand to benefit if the party’s presidential nominee can persuade some voters not to split their ticket in 2024 and vote for a GOP senator as well. Considering how red West Virginia and Montana are today, such a shift could be enough for Republicans to flip those two seats and win the Senate even if the GOP loses the presidency, should the pool of split-ticket voters shrink even further.
With Georgia’s runoff in the rearview mirror, the 2024 election cycle can truly begin. And while the Democrats’ victory in the Peach State has helped give them a bit of wiggle room in the Senate, the overall map remains favorable to Republicans. To hold onto the Senate, Democrats need a lot of things to go right in 2024. While the 2022 midterm result showed how that can happen, Democrats will probably have to retain at least a couple of seats that are redder than any they had to defend this year — a difficult task in a world with fewer split-ticket outcomes between presidential and Senate voting.