It’s been known for a while now that the Democrats' prospects for holding onto the Senate in 2024 aren’t very good. The biggest problem they have is that they will being defending 23 seats, while the GOP only has to defend 10 seats. And many of the seats Democrats will be fighting to hold are in red and battleground states. So it’s no secret that the 2024 Senate map is very positive for the GOP. Indeed, Republicans are favored to win back the majority. In fact, certai forecasts suggest that if the GOP wins the majority in 2024, it may be a few cycles before Democrats can realistically regain it. This means that the bigger the majority that Republicans can secure in 2024, the safer the upper chamber will be against a potential shift back to Democratic control.
So, which seats are most likely to flip from blue to red? Let’s take a look.
West Virginia
The writing has been on the wall for some time in West Virginia. Sen. Joe Manchin was likely the Democrats' best chance at holding the seat, since he’d managed to win reelection in the deep red state multiple times. However, his margin of victory had steadily decreased in each Senate election since 2012. West Virginia Gov. Jim Justice, a leading contender in the GOP primary for the U.S. Senate, has consistently held a double-digit lead over Manchin. Earlier this month, however, Manchin announced he wouldn’t seek reelection.
This should be an easy flip for the GOP.
Ohio
Ohio has gone from a bellwether battleground state to a reliably red state in recent cycles. The Trump-backed Republican J.D. Vance won in 2022 by a comfortable six-point margin, which was a clear warning sign for incumbent Democrat Sherrod Brown, who was first elected to the Senate in 2006. Recent polling not only shows Ohio Secretary of State Frank LaRose currently leading the pack of Republicans vying for the Republican nomination, but also shows a tight race in the general election. Brown first managed to get elected in 2006, a bad year for Republicans, and has continued to be reelected in cycles advantageous to Democrats. In 2012, he was reelected at the same time Barack Obama won the state. He was also reelected in 2018—a year that, even though Republicans held the Senate, was widely considered a blue wave election year as Democrats won a net of 41 House seats. Turnout in 2024 in favor of Donald Trump (who last won the state by eight points) could help send Sherrod Brown packing.
Montana
Democrat Sen. John Tester has only barely won his past two elections by about 18,000 votes. Despite hailing from a red state, Tester votes like a blue state Democrat and has always been seen as vulnerable when he is up for reelection. The last time Tester ran for reelection during a presidential election year was in 2012, and Barack Obama was still somewhat popular then. Joe Biden, however, is not, and he will most likely be a tremendous drag on Tester this time around.
Nevada
I’ve long written off Nevada, but Trump barely lost the state in 2020 and 2016, and recent polling shows Trump ahead there with an RCP average of spread of +4 points. Sen. Catherine Cortez Masto (D-Nev.) only narrowly won reelection last year, and Republican Joe Lombardo managed to win the governorship, which tells you that Nevada is very competitive. If recent polling is to be believed, it’s conceivable that Trump on the ballot could help the Republican nominee in Nevada.
Arizona
I am admittedly not confident about Arizona because Kari Lake is the frontrunner for the GOP nomination. That said, I fully admit that recent polling shows a close race that is potentially winnable, despite voters' negative perceptions about her. For what it’s worth, Donald Trump is also performing better in Arizona this cycle. In fact, all Republican primary candidates are outperforming Joe Biden in the polls there. Will that be enough to overcome Lake’s negative approval ratings? I’m not sure. I predict it will be a close race regardless.
Pennsylvania
I originally had little hope for flipping the seat currently held by Sen. Bob Casey (D-Pa.), but that was when Doug Mastriano, who got clobbered by Josh Shapiro in the Pennsylvania gubernatorial race in 2022, was the GOP frontrunner. Mastriano has since decided not to run, and former hedge fund CEO David McCormick appears to be Casey’s likely Republican challenger. While Casey previously won reelection by double digits in 2018, running for reelection in 2024 will be quite different. Recent polling shows Trump ahead in Pennsylvania, which could make McCormick competitive. Recent polling shows Casey up 7 points over McCormick, but if Trump is the nominee and is indeed ahead of Biden in the state, he could help bring McCormick over the finish line.
