The 10 Senate seats most likely to flip in 2024

With just over a month until Election Day, the same competitive races continue to dominate the Senate landscape, but there are a few significant changes to the order of CNN’s ranking of the seats most likely to flip.

And in the final weeks, the degree to which these 10 races – which are mostly playing out in states Donald Trump either won or narrowly lost in 2020 – move in the same direction as the presidential contest will likely determine which party wins control of the Senate.

Republicans – who are virtually a lock to pick up the West Virginia seat and would need to either win the White House or pick up one more seat for the majority – have an incentive to nationalize many of their targeted races. Well-funded Democratic incumbents, for the most part, are touting statewide and local accomplishments and their support for abortion rights.

Two states that are part of the Democratic “blue wall” – and also key White House battlegrounds – move up on this month’s rankings, which are based on reporting, as well as fundraising, polling and advertising data. Pennsylvania and Wisconsin are now in the middle of the pack of flippable seats, along with Michigan, which remains at No. 4.

The oddity of this year’s fight for the Senate is that Democrats have consistently led in the public polling of key races, but it’s Republicans who are poised to gain seats and, potentially, control of the chamber.

That’s a reflection of the Senate map – but also increasingly some post-Labor Day tightening as GOP spending picks up and voters get to know their candidates. Still, no public general election polling that meets CNN standards has shown the Republican nominee ahead in any of the seats that Democrats are defending, save for West Virginia.

And two GOP targets – Arizona and Nevada – are moving down the list because Republicans have not kept the races as competitive as elsewhere. Earlier this year, those two states were Nos. 4 and 5. Now, they’re at 7 and 8.

At the same time, Democrats are trying to expand the map in hopes of mitigating potential losses. As CNN first reported last week, the Democratic Senatorial Campaign Committee is making multimillion-dollar TV investments in Texas and Florida. DSCC Chairman Gary Peters has insisted that this is extra spending that won’t take money away from their defensive priorities. Texas remains at No. 9 on CNN’s ranking, while Florida fell off the list earlier this year in favor of the race in deep-blue Maryland.

Nebraska is a new state generating political buzz, but it hasn’t earned a place on the ranking. Still, independent Dan Osborn’s challenge to GOP Sen. Deb Fischer has prompted the National Republican Senatorial Committee to start spending here, and elections analysts have moved the race out of the solid Republican category.

There remain lots of unknowns in Nebraska, but we’ll be watching to see how that race – and the 10 others – develop over the next month.

West Virginia is essentially out of reach for Democrats, who had little chance of holding this seat without Sen. Joe Manchin running for reelection. Manchin, now an independent who caucuses with Democrats, is likely to be succeeded by Republican Jim Justice, the state’s two-term governor.

Justice has had his share of negative headlines, but in a state poised to back Trump by a significant margin, it’s hard to see a world in which Republicans don’t pick up this open seat.

Democrat Jon Tester, who’s running for a fourth term in a state Trump has twice carried by double digits, remains the most vulnerable Senate incumbent this year. Republicans feel confident their nominee, Tim Sheehy, has an edge – and both Inside Elections with Nathan L. Gonzales and the Cook Political Report with Amy Walter have shifted their rating of the once toss-up race toward the GOP.

Democrats still see a path to victory for Tester, who has a proven history of defying the partisan lean of his state by communicating both what he’s done for Montanans and painting a contrast with his opponents.

Democrats are trying that playbook against Sheehy, trying to define the wealthy businessman and retired Navy SEAL, who moved to Montana in 2014, as an out-of-state carpetbagger who cannot be trusted. Recently unearthed audio recordings of Sheehy using racist stereotypes to refer to Native Americans has played into that message, with Democrats arguing that he’s alienating a crucial demographic in the state. In a debate earlier this week, Sheehy acknowledged his comments were “insensitive,” saying, “I come from the military as many of our tribal members do. You know, we make insensitive jokes and probably off-color sometimes.”

Tester’s campaign is now leaning into abortion rights on the airwaves – an issue that’s on the ballot in Montana this year. A recent ad features a self-described “life-long” Republican woman arguing that Sheehy “wants to take away personal freedoms.”

But Republicans are invoking transgender issues in an attempt to cast Tester as a liberal who’s been changed by his years in Washington, while Sheehy is trying to tie Tester to Kamala Harris – especially on immigration. Tester – who has not endorsed in the presidential race – tried to meet those attacks during their debate by pointing out that Sheehy would not have supported this year’s bipartisan border bill that Republicans blocked.

Democratic Sen. Sherrod Brown is facing his toughest reelection in a state that has twice backed Trump by 8 points. Public polling still shows the three-term senator ahead of GOP nominee Bernie Moreno, although that is expected to tighten as more Republican voters come home to Moreno. Brown was at 47% to Moreno’s 43% in a late September New York Times/Siena College poll among likely Ohio voters – not far outside the margin of error. But the reassuring news for Democrats: Brown was winning 10% of Trump voters.

Democrats have seized on Moreno’s recent comments at a town hall suggesting that some suburban women were single-issue voters when it comes to abortion and questioning why women over 50 would care about the topic. Brown pointed to the remarks as evidence that his opponent is out of step with the 57% of Ohio voters who last year approved a ballot measure protecting reproductive rights. WinSenate, a Democratic outside group, also launched a new ad with a woman talking about the emergency abortion she underwent at 25 for an ectopic pregnancy, saying, “Our lives don’t belong in Bernie Moreno’s hands.”

(Moreno’s campaign said in a statement that he was “clearly making a tongue-in-cheek joke about how Sherrod Brown and members of the leftwing media like to pretend that the only issue that matters to women voters is abortion,” and that Moreno believes women “care just as much about the economy, rising prices, crime and our open southern border as male voters do.”)

The Senate contest in Ohio ranked as the most expensive congressional race on record, as of October 3, with total ad spending from both parties this cycle, including future reservations, exceeding $446 million, according to AdImpact. Brown – who announced raising $30.6 million in the third quarter – has continued to tout his work to pass the PACT Act to help veterans exposed to burn pits, while Moreno tries to nationalize the race by tying Brown to Harris and inflation and linking himself to Trump. The Senate Leadership Fund, a super PAC tied to GOP leadership, is attacking Brown over transgender issues to try to cast him as out-of-step with the partisanship of the state.

Michigan remains the most competitive open seat on this list. Democrat Elissa Slotkin has held a narrow edge in the race to succeed retiring Democratic Sen. Debbie Stabenow, but the absence of an incumbent and the competitiveness of the presidential race in the Wolverine State makes it one that could come down to the wire.

Slotkin, a third-term congresswoman, led Republican former Rep. Mike Rogers 47% to 42% among likely voters in a late September New York Times/Siena College poll, with Slotkin drawing 6% of likely voters who also said they would vote for Trump. Slotkin has a strong fundraising record – her campaign announced raising $18 million in the third quarter – but Republicans are pouring more money into this state, with the Senate Leadership Fund recently announcing a $22.5 million investment.

Slotkin has been running ads on abortion – an issue that has helped propel recent Democratic victories in the state. Her spots claim that Rogers’ past support for abortion restrictions makes him untrustworthy on the issue now. “I’m scared that Mike Rogers will continue to take away my rights,” says one woman in a spot who says she needed an abortion to save her life.

Rogers has been responding on air, speaking directly to camera while holding hands with his wife in one new spot, saying he respects Michigan voters’ decision on abortion rights and “won’t do anything to change it” in the Senate.

Rogers, the former chairman of the House Intelligence Committee, scored the endorsement of the state Farm Bureau’s PAC, which had previously backed Stabenow (the chair of the Senate Agriculture panel). Rogers, whom Democrats have attacked for living in Florida after he left Congress a decade ago, is running spots that tout his Michigan roots and public service. Rogers and Republicans are also attacking Slotkin and the Biden administration over plans to support the building of electric vehicles, using the misleading term “mandate.”

Democratic Sen. Bob Casey’s race against Republican challenger Dave McCormick moves two spots up on the list in light of heavy GOP outside spending, some tighter polling and the competitiveness of the presidential race in a state that is part of Democrats’ so-called blue wall of must-win states.

September polling from Marist, Quinnipiac University, the New York Times/Siena College/Philadelphia Inquirer, Franklin & Marshall, CBS News/YouGov and Fox News all gave Casey anywhere from a 5- to 9-point lead among likely voters. Polls from CNN and The Washington Post around the same time, however, showed no clear leader.

The two candidates, who met on the debate stage for the first time Thursday night, have been hitting the airwaves with competing messages, as have their allied outside groups. Democrats are going after McCormick on abortion, including one ad that features footage of him referring to himself as “pro-life.” The Senate Leadership Fund, which is adding $28 million to GOP sending here, and the pro-McCormick Keystone Renewal PAC have been attacking Casey over inflation and immigration.

McCormick’s tenure as the CEO of FreeMarkets – a Pittsburgh-based software company – has also been featured in ads on both sides. The Democratic group WinSenate is accusing him of outsourcing jobs and pointing to his management of the company to argue that “Connecticut Dave”  – he owns a home in the Nutmeg State – “wants to buy our Senate seat.” McCormick is running ads featuring former FreeMarkets employees praising him and touting the company’s hiring policies.

Wisconsin also moves up two spots on the list amid signs that some Republicans could be drifting home toward their party’s nominee, Eric Hovde, in his challenge to Democratic Sen. Tammy Baldwin.

The two-term senator maintained a modest edge over Hovde in a Marquette University Law School poll released this week – 51% to 45% among likely voters when third-party candidates are included and 53% to 46% in a head-to-head matchup. Baldwin had a similar 7-point lead in a New York Times/Siena College survey of the two-person race taken around the same time.

While Baldwin has repeatedly outraised Hovde, the Senate Leadership Fund is also pouring funds – $17 million – into the Badger State, and Hovde has plenty of his own money to pay for ads at the lower candidate rate if he chooses. (We’ll be eying his third-quarter fundraising filing for details about how much the Sunwest Bank CEO had loaned his campaign through September.) Ads from Hovde – whose campaign recently underwent a shakeup – have sought to tie Baldwin to Harris, attacking her over border security, fentanyl and transgender rights.

But Baldwin, who’s made an effort to visit the red, rural parts of Wisconsin, has a well-defined brand. She picked up the endorsement of the Wisconsin Farm Bureau Federation this week – a notable get for a Democrat running statewide. Much of Democratic advertising has played up Hovde’s past controversial comments and sought to cast him as a California carpetbagger – he owns property in Laguna Beach, even though he was born and raised in Wisconsin and his family’s company is a prominent state brand.

Arizona is a conservative-leaning purple state, where Republicans should ordinarily be able to pick off a Senate seat – especially an open one. But in the race to replace retiring Sen. Kyrsten Sinema, an independent who caucuses with Democrats, Republican candidate Kari Lake seems to have hit a ceiling.

The 2022 gubernatorial nominee is well known in the state, but not necessarily for the right reasons. She still refuses to accept her loss for governor and, despite tethering herself to Trump, is underperforming his polling numbers.

Democratic Rep. Ruben Gallego led Lake by 10 points among likely voters in a Marist poll and 13 points in a Fox News survey, both from mid-September. Lake was polling behind Trump in both surveys by 6 points and 8 points respectively.

Lake and the NRSC are blaming Gallego for inflation and immigration – pointing to his support for what they’re calling the “Kamala Inflation Act.” (Harris cast the tie-breaking vote in the Senate for the Inflation Reduction Act in 2022.) And while the Senate Leadership Fund hasn’t spent here, a Club for Growth-affiliated group is also airing attacks on the congressman. Gallego, a former member of the Congressional Progressive Caucus, was on the airwaves for months introducing himself to voters statewide as a Marine veteran and is touting his support from law enforcement and Republican voters. He announced raising $21.7 million in the third quarter.

Nevada moves down two spots on the list as Democratic Sen. Jacky Rosen appears to be in a stronger position against Republican opponent Sam Brown in a state where Democratic prospects seem to have picked up since Harris ascended to the top of the ticket.

Rosen, who appeared at a Harris rally in Las Vegas earlier this week, led Brown by 10 points in a CNN poll in late August. Like Lake in Arizona, Brown – an Army veteran who first ran for office in Texas and lost the GOP primary for Nevada’s other Senate seat last year – also appears to be running up against a ceiling.

Rosen and Democrats are hitting Brown over his previous stances on abortion – which is on the ballot this year in Nevada. Brown, who says he supports current state law legalizing the procedure up to 24 weeks, has said he’d “close the door” on backing a national abortion ban.

Rosen has had a fundraising edge over her opponent, and this week, national Republicans canceled their remaining independent expenditures in the state in favor of running hybrid ads with Brown, which allows them to benefit from the lower candidate rate in the ultra-pricey Las Vegas media market — a strategy they’ve employed in races across the country to try to compete with well-funded Democratic candidates on the airwaves.

National Democrats’ decision to invest TV resources in Texas was the first major signal the party is putting money where its mouth is on the competitiveness of the Lone Star State this year. Democrats see Republican Sen. Ted Cruz as unpopular and his Democratic challenger, Rep. Colin Allred, as the man to beat him, even in a state that is still comfortably red at the presidential level.

The first hybrid ad between Allred and the DSCC features Kate Cox, the woman who had to leave the state to seek an abortion after her fetus had been diagnosed with a deadly condition, and Amanda Zurawski, who sued the state after she was denied an abortion when experiencing complications. “If you’re experiencing pregnancy complications in Texas, you’re in danger,” Zurawski says in the ad, “and it’s Ted Cruz and the anti-abortion extremists’ fault.”

Allred has also tried to flip the script on Republicans by accusing Cruz of “doing nothing to secure the border.” Cruz, in turn, is attacking Allred over a vote related to the inclusion of transgender athletes in women’s sports. “Boys and girls are different,” is how another ad from the Republican opens. “This election is about keeping Texas Texas,” Cruz has said.

Cruz only beat Democrat Beto O’Rourke by 3 points in 2018. But Democrats hope that Allred, a former NFL player who flipped a Dallas-area House seat the same year, is a more formidable challenger and can turn out more minority voters. (Allred would be the state’s first Black senator if he wins.)

Even Republicans acknowledge that Allred is running a good race, and the NRSC is investing here to help Cruz and the state party. Still, Democrats have not won a statewide election in Texas since 1994, so this remains an uphill battle for Allred.

10. Maryland

The race to succeed retiring Democratic Sen. Ben Cardin remains in tenth place this month as Angela Alsobrooks fights to keep this seat in party hands. Joe Biden won Maryland by 33 points in 2020, but Republican nominee Larry Hogan – a popular former two-term governor – has a supportive super PAC committing $18 million to tout his independence.

Alsobrooks, the Prince George’s County executive, led Hogan by 11 points in a recent Washington Post/University of Maryland poll. She’s become better known statewide and has made gains among voters who say they care about Democrats maintaining control of the Senate. The argument that Hogan would be another vote for Senate Republicans has been Democrats’ central pitch in deep-blue Maryland, especially on abortion rights and Trump.

Voters in the Post survey were split over whether Hogan would back his party’s leaders in the Senate. He’s winning nearly half of independents, as well as 18% of Democrats. And as he tries to combat Democratic attacks over abortion rights, he’s run ads about being “the ultimate girl dad” and “one of the few Republicans who never caved” to Trump. Hogan rejected the former president’s endorsement earlier this year, but Democrats quickly seized on Trump saying that he’d like to see Hogan win.

Maryland’s Future, the super PAC backing Hogan, is trying to localize the race by attacking Alsobrooks for improperly taking advantage of tax breaks she did not qualify for, as first reported by CNN. (Her senior adviser told CNN that she was unaware of the problem and that her attorneys are working with both the District of Columbia and Prince George’s County to resolve the issue.)

CNN’s David Wright contributed to this report.