The 10 Senate seats most likely to flip in 2024

By Simone Pathe, CNN

(CNN) — Senate control is for grabs Tuesday. And although Republicans are well positioned to win the majority, Democrats cannot be counted out entirely.

That’s because their well-funded candidates have consistently overperformed the top of the ticket in polling of many of the most important races. And even as the Senate map has become more daunting for Democrats with West Virginia Sen. Joe Manchin retiring, opportunities to mitigate GOP gains have opened up in Texas and, increasingly, Nebraska.

With Manchin almost certain to be succeeded by a Republican, the GOP needs to either pick up one more Senate seat or win the White House to flip the chamber. That math puts the pressure on Democrats to hold all their competitive seats while trying to knock off Republicans in Texas and Florida.

The battle for the Senate has evolved over the past two years, and CNN’s rankings of the top 10 seats most likely to flip – which is based on our reporting, as well as polling, fundraising and advertising data – has reflected those shifts.

Senate seats in the three states that Donald Trump won twice (West Virginia, Montana and Ohio) have always been the most likely to flip. Democrats aren’t trying to defend West Virginia. In Montana and Ohio, Sens. Jon Tester and Sherrod Brown, respectively, have defied partisan gravity before, even when several of their red-state colleagues lost in 2018. But that’s looking increasingly difficult with the decline of ticket-splitters.

The three “blue wall” states of Michigan, Pennsylvania and Wisconsin – which are also crucial presidential battlegrounds – started the cycle looking more comfortable for Senate Democrats. But the races there have all tightened in the final months of the campaign as GOP groups ramped up spending and Republican voters coalesced around their nominees.

Those three races are finishing out the year in the middle tier of the rankings, with Wisconsin moving up two spots – from No. 6 to No. 4 this month. (It was at No. 8 two months ago.) Democrats see the Badger State, which reelected Republican Sen. Ron Johnson two years ago, as the demographically toughest for them of the three blue wall states. Michigan, which was once seen as trickier for Democrats to hold as an open seat, slides down one spot because of Democratic nominee Elissa Slotkin’s relative strength compared with her GOP opponent. Pennsylvania is at No. 6. However, all these races are still very close, and a lot may depend on how Vice President Kamala Harris fares in each state.

The two Sun Belt states of Nevada and Arizona started off the year higher on CNN’s ranking – in part because of demographic challenges for Democrats there – but they’re finishing at the bottom of the pack of the party’s defensive seats. Democrats have been outspending Republicans in both states in the final month of the campaign, including in future reservations through Election Day, according to data from ad tracking firm AdImpact. Of all the top states, the largest Democratic spending disparity is in Arizona, where the super PAC aligned with Senate Minority Leader Mitch McConnell never came in to help GOP nominee Kari Lake.

Democrats’ best offensive pickup opportunity comes in at No. 9. Flipping Texas is still a tall order, but there’s more Democratic confidence about defeating Sen. Ted Cruz than there was six years ago.

The last spot on the list has changed the most. At the beginning of the cycle, it was held by Florida, where Democratic former Rep. Debbie Mucarsel-Powell is trying to unseat Republican Sen. Rick Scott. Despite an abortion measure being added to the ballot this year, which could boost Democratic chances in this reddening state, Florida soon fell off the list in favor of Maryland. The candidacy of Republican Larry Hogan, a popular former two-term governor, made it look tougher for Democrats to hold a seat in a state that backed Joe Biden by more than 30 points four years ago. However, Democrat Angela Alsobrooks has effectively made this race about Senate control – something most Maryland voters aren’t eager to hand over to the GOP.

There’s still a chance Democrats flip Florida (which is rated Likely Republican by Inside Elections with Nathan L. Gonzales) or Republicans flip Maryland (rated Likely Democratic.) But we close the cycle with a new No. 10 – Nebraska. The deep-red state graces the list for the first time because of independent Dan Osborn’s challenge to two-term Republican Sen. Deb Fischer. Her loss wouldn’t necessarily flip the seat to the Democrats, since Osborn hasn’t said which party he’d caucus with in Washington. But with Democrats trying to stave off a GOP majority, an Osborn win would deprive Republicans of a key seat.

This race (rated Lean Republican) still favors Fischer, but millions in GOP spending over the final weeks is enough to raise eyebrows.

Since Labor Day weekend, Democrats have slightly outspent Republicans by about $696 million to $668 million across the races listed below, excluding uncompetitive West Virginia and wild-card Nebraska, where pro-Osborn advertisers have bested their pro-Fischer counterparts by about $24 million to $16 million.

And in an election cycle projected to be the most expensive ever, according to AdImpact, and one that features the costliest congressional race on record – the Senate election in Ohio – big money has played a major role in each side’s effort. A pair of leading outside groups, one from each party, combined to account for about 34% of all ad spending on Senate races between Labor Day and Election Day – at more than $550 million – with no other advertiser accounting for more than 5%.

Here are the final rankings ahead of Tuesday’s election:

1. West Virginia

The race to replace retiring independent Sen. Joe Manchin is likely to give Republicans their easiest pickup of election night. Gov. Jim Justice is well positioned to win this open seat, with Trump expected to carry the state by a significant majority. (He won nearly 70% of the vote here in 2020.)

Democrats stopped contesting this seat after Manchin, who still caucuses with his former party, said he wasn’t running again. And while that’s allowed them to spend elsewhere, it’s dramatically complicated Democrats’ precarious math to hold the Senate.

2. Montana

Democratic Sen. Jon Tester is the most vulnerable incumbent running for reelection, and with West Virginia already essentially gone, he’s under enormous pressure to defy the partisanship of his ruby-red state. He’s done it before – even winning a third term in 2018, two years after Trump had carried the state by more than 20 points. But in an increasingly nationalized political environment, with fewer ticket-splitters, it may be harder to pull off such a feat again, regardless of how strong Tester’s brand as a seven-fingered dirt farmer is back home.

He’s facing Republican businessman Tim Sheehy, a retired Navy SEAL and first-time candidate who has pulled ahead in the limited public polling of the race. National Republicans and Sheehy are tying Tester to Biden and Harris to make an anti-incumbent argument, while the Senate Leadership Fund, the leading Senate GOP super PAC, slams Tester as “Washington at its worst.”

Tester has tried to paint Sheehy, who moved to Montana in 2014 after leaving the military, as a wealthy out-of-stater who’s a threat to Montanans’ access to public lands and abortion rights. (Montana has also an abortion rights measure on the ballot this year that Democrats are hopeful could boost their chances.) And he’s called Sheehy out over making offensive comments about Native Americans – a key constituency that Democrats have invested historic sums to reach on the ground this year.

In the closing weeks of the race, various Democratic groups have also focused on Sheehy’s conflicting story from nearly a decade ago about how a bullet ended up lodged in his arm to attack his truthfulness. Last Best Place PAC is up with an ad featuring the park ranger whom Sheehy told that his gun had accidentally discharged in Glacier National Park. WinSenate has launched a spot featuring a retired Navy SEAL who served with Sheehy and insists the candidate didn’t receive the bullet wound in Afghanistan, saying, “There’s no honor in lying about your service.” Tester’s campaign, too, is featuring veterans accusing Sheehy of being a liar.

Still, the odds are against Tester. An early loss here on Tuesday isn’t necessarily indicative of how the rest of the night will go for Democrats given how red this state is. But it would be bad news for their efforts to hold the Senate.

3. Ohio

Democrat Sherrod Brown is the second most vulnerable senator as he fights for a fourth term in a state that’s moved solidly away from Democrats. The progressive populist, first elected in 2006, is the only remaining Democrat in nonjudicial statewide office. He held a comfortable edge in public polling for much of the year over GOP challenger Bernie Moreno, a Cleveland car dealership owner whom Democrats boosted in the primary because they thought he’d be the weakest general election opponent. But the race has tightened as late GOP super PAC spending flooded the state and more Republicans got to know their Trump-backed nominee.

One of Moreno’s closing ads features Trump criticizing Brown, and Republicans are arguing that the senator has changed and is too liberal for Ohio. The Senate Leadership Fund is running ads featuring women who say, “I thought I knew Sherrod Brown. Now I hear he’s super liberal,” pointing to abortion and transgender athletes. (Brown and the Democratic Senatorial Campaign Committee are up with a response ad on the latter issue that says the senator agrees with GOP Gov. Mike DeWine that “these decisions should be made by local sports leagues, not politicians.”)

Brown is leaning into the issue of abortion, seizing 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. “Bernie Moreno, I am 100 years old, and I am definitely not crazy,” one woman says in an ad. “Bernie Moreno thinks he knows better than us,” says a woman in another ad, which points out that 57% of Ohioans approved a ballot measure protecting reproductive rights last year.

Brown is also touting the support of Republicans – both in his ads, which often have featured members of law enforcement, and now with the endorsement of former Gov. Bob Taft, who noted Brown’s seniority in the Senate and his work across the aisle. But that may not be enough to save Brown with the state primed to vote red at the top of the ballot once again.

4. Wisconsin

Wisconsin moves up two spots in the final rankings. It’s the major race where the Republican nominee has delivered in a significant way on the party’s hopes that a self-funding candidate could close the gap with a well-funded Democratic incumbent. Sen. Tammy Baldwin, first elected in 2012, looked to be in a relatively comfortable position this summer, even when Biden was the nominee. But Republican Eric Hovde’s late spending – he’s poured at least $20 million of his own money into the race – has tightened things in a state that was always expected to be close.

There was no clear leader in a CNN/SSRS poll of the race released Wednesday, with Baldwin at 49% to Hovde’s 47% among likely voters. (Harris led Trump 51% to 45% in the same survey, although CNN’s latest average of Wisconsin polling shows no clear leader in the presidential race.) A Marist survey released Friday showed a similarly close 51% to 48% race among likely voters, with Hovde’s image more unfavorable than Baldwin’s. By contrast, a CNN poll conducted in August found Baldwin leading by 6 points.

Democrats were up on air early to try to define Hovde as a California banker, frequently reminding voters that the Sunwest Bank CEO owns a home in Laguna Beach and was once named one of Orange County’s most influential people. (Hovde was born and raised in Wisconsin, and his family’s company is a prominent state brand.) Baldwin – who scored the endorsement of the Wisconsin Farm Bureau Federation this year – has a history of making inroads in the red parts of her state, while Democrats think the issue of abortion rights will help them pick up nontraditional Democratic voters. But this is a much tougher election than the one Baldwin faced in 2018.

And in the final stretch, Hovde and his GOP allies have been accusing Baldwin, the first out gay senator, of a conflict of interest because her partner of six years is a financial adviser for high-end clients. The charge, which Baldwin strongly denies, lacks proof. They’ve also been attacking her over transgender issues, trying to put the senator on defense. (She’s responded with ads that call Hovde a liar, arguing, “He’s not for us.”) But the GOP attacks may be helping Hovde, who started out relatively unknown, consolidate the base.

5. Michigan

With Democratic Sen. Debbie Stabenow retiring, this open seat had long been ranked as the most competitive of the “blue wall” states. It slides down one spot on the list, however, with Rep. Elissa Slotkin appearing in a slightly stronger position than other Democrats and her GOP opponent looking weaker.

The three-term congresswoman, who is making her first statewide run, has had a healthy fundraising advantage over Republican former Rep. Mike Rogers for much of the cycle. She had a slight edge over Rogers, 48% to 42% among likely voters, in a CNN/SSRS poll released Wednesday, while a Washington Post survey around the same time found no clear leader, with Slotkin at 48% to Rogers’ 45%. A Marist poll released Friday, which gave Slotkin a 6-point edge, also showed her with stronger favorability numbers than her GOP opponent.

In the CNN poll, Slotkin was winning independents by 20 points, but both she and Rogers were pulling in the mid-single digits among those who said they were voting for the opposite party’s presidential nominee. The latest CNN poll of polls, which tracks the average polling result, shows no clear leader between Harris and Trump in Michigan.

Slotkin picked up the endorsement of GOP former Rep. Liz Cheney, who supported the congresswoman in her 2022 reelection and has been on the trail for Harris in Michigan, which could help both women appeal to some Republicans disaffected with Trump. Rogers, meanwhile, has cozied up to the former president after initially saying he bore responsibility for the January 6, 2021, attack on the US Capitol.

Democrats have attacked Rogers, the former House Intelligence chairman who moved to Florida after he left the chamber in 2015, over abortion – pointing to his past votes for restrictions. Rogers and Republicans are attacking Slotkin over transgender issues and electric vehicles. (Slotkin has run her own ad pointing out she lives on a dirt road and doesn’t drive an EV, but that she wants the “next generation” of cars to be made in Michigan.)

Slotkin’s closing ad repeats much of her introductory message – that she served three tours in Iraq as a CIA analyst, worked under presidents of both parties and is committing to protecting health care access after watching her mom suffer from cancer.

Michigan – one of the must-win blue wall states for Harris – has been a point of concern for some Democrats because of anger among the state’s significant Arab American community over the Biden administration’s handling of Israel’s war in Gaza. It remains to be seen whether that will extend to Slotkin’s race. But as CNN has reported, a GOP-linked group has targeted digital ads and mailers to Arab voters promoting Slotkin’s and Harris’ support for Israel.

6. Pennsylvania

The race to unseat Democratic Sen. Bob Casey has also tightened in the final weeks, but that’s to be expected in a battleground state, where the three-term senator is facing his toughest challenge, from Republican Dave McCormick.

Casey was at 50% to McCormick’s 47% among likely voters in a Quinnipiac poll released Wednesday. (The same poll from earlier in October found the Democrat leading 51% to 43%). A CNN/SSRS poll, also released Wednesday, put Casey at 48% to McCormick’s 45% among likely voters. In both recent surveys, Casey was winning independents by at least 10 points.

The latest CNN poll of polls of the presidential race in Pennsylvania shows no clear leader. That’s one reason why Casey has been touting his appeal across the aisle. “On politics, we just don’t agree – except on Bob Casey; he’s independent,” says one half of a bipartisan couple in a recent Casey spot. The Republican wife goes on to cite examples where the senator “bucked Biden” and “sided with Trump.”

Democrats have also gone after McCormick on abortion, trying to paint the Republican as an extremist. (McCormick has countered that it’s Casey who’s the extreme one.) McCormick’s trips back to Connecticut (where his school-age daughter lives) and business background have also been a frequent source of attacks, which in some cases have prompted response ads from McCormick featuring his former employees.

The former Bridgewater CEO, who lost out on the Trump endorsement in the 2022 Senate primary before winning it this year, has had some trouble consolidating the former president’s base. (In both the Quinnipiac and CNN surveys, for example, he’s winning less than 90% of Republicans.) But he’s appeared at Trump rallies throughout the year, while also recently campaigning with former South Carolina Gov. Nikki Haley, who earned 16% of the presidential primary vote in Pennsylvania this spring, despite having already dropped out of the race.

McCormick is making an anti-incumbency argument, calling Casey “too weak” and asking voters in one of his closing messages to “make a change,” while recapping his bio as a West Point graduate.

7. Arizona

The race to succeed retiring Sen. Kyrsten Sinema, who left the Democratic Party to become an independent, shows how important candidate quality can be.

Republicans should be having an easier time picking up this Senate seat, in a state Biden barely won in 2020. But Republican nominee Kari Lake is underperforming Trump in most polls here, while Democratic Rep. Ruben Gallego – a former member of the Congressional Progressive Caucus – is finding appeal across the aisle.

Gallego led Lake 51% to 43% among likely voters in a CNN/SSRS poll released Tuesday. (The presidential race was neck and neck with Harris at 48% to Trump’s 47%.) The congressman was winning 11% of Republicans and 7% of likely voters who said they were voting for Trump. Gallego, who was unopposed in the Democratic primary, went up on the air early, introducing himself to statewide voters as a Marine veteran who wants to secure the border and protect abortion rights. And he recently got some help telling that story from the state’s junior senator, Democrat Mark Kelly, who appears in a spot for him.

Lake – who has alienated parts of the GOP by insulting “McCain Republicans” – is touting former Gov. Doug Ducey’s endorsement in a recent ad. (There was a time when national Republicans were hopeful that Ducey, a more moderate Republican, might run himself.)

But Lake, the 2022 Republican gubernatorial nominee, still refuses to acknowledge she lost the governor’s race. “I want to make sure our elections are run properly, and I’m still in litigation, so I don’t want to speak to that. But I do want to look forward,” she told CNN’s Kaitlan Collins on Monday.

8. Nevada

Democratic Sen. Jacky Rosen looks to be ending the cycle in a safer place than when she started, in a state where Democrats have long feared that demographics are trending away from them. (In April, for example, Nevada ranked No. 4 on this list – the most competitive of the Biden-won states.)

But Republican Sam Brown, an Army veteran who lost the 2022 primary for the state’s other Senate seat, has struggled to take off as the nominee this year. Rosen led 50% to 41% among likely voters in CNN/SSRS polling released Tuesday. (There was no clear leader in the presidential race.)

The first-term senator was up on air early, attacking Brown over his position on abortion before he had even made it out of the June primary. And while abortion has been the major attack line from Democrats – namely that Brown once supported tougher restrictions as a candidate for the Texas House – Rosen has also tried to keep things local. She’s touted her efforts to save a mail processing facility in the state, for example, while also targeting the Filipino American community with ads that highlight her work to lower prescription drug prices.

Brown, meanwhile, has leaned into the endorsement of Trump, who praised him at a Thursday night rally, where he said the Senate race was neck and neck. Brown and the National Republican Senatorial Committee are running an ad that splices in Trump’s criticism of Rosen from an earlier rally. But Brown was still underperforming the former president’s vote share by 7 points in CNN’s recent Nevada survey.

9. Texas

If there’s one glimmer of hope for Democrats looking to mitigate losses on Tuesday, it’s Texas. The race to unseat Republican Sen. Ted Cruz has moved from an improbable long shot to one Democrats seriously believe could be within their grasp, with both the DSCC and Senate Majority PAC making multimillion-dollar investments here.

That’s in large part because of confidence in Rep. Colin Allred and a belief that he’s better positioned than Democratic nominee Beto O’Rourke was six years ago, when he lost to Cruz by less than 3 points. Allred has proved to be a strong fundraiser who’s tried to weaponize the state’s abortion ban against Cruz while also going on offense on border security. An ad from the DSCC and Allred, for example, features border law enforcement officers slamming Cruz for not supporting the bipartisan border bill, saying, “Colin’s got our back.”

Kate Cox, whom the state Supreme Court blocked from having an abortion after her fetus was diagnosed with a deadly genetic condition, has played a central role in Allred’s advertising. Underscoring the salience Democrats see in abortion rights messaging this year, Allred recently appeared with Harris – who’s not contesting Texas – for a major rally in Houston, where she argued that the state’s ban was an example of what Trump’s America could look like.

Allred, who first flipped a Dallas-area House seat in 2018, trailed Cruz 46% to 50% among likely voters in a recent New York Times/Siena College poll. He’s keeping things much more competitive than Harris – winning a higher percentage of Black and Latino voters than the Democratic presidential nominee and pulling 9% of likely voters who said they were voting for Trump. But Cruz and his GOP allies are trying to yoke Allred to Harris on transgender issues, inflation and the border wall. Allred, a former NFL player, was the first Democratic Senate candidate to respond on air to that growing GOP attack line over transgender athletes, saying, “I don’t want boys playing girls’ sports or any of this ridiculous stuff that Ted Cruz is saying.”

10. Nebraska

Nebraska is appearing on this list for the first time, with Republican Sen. Deb Fischer facing a more competitive reelection bid than expected in the final stretch.

Fischer was at 48% to independent Dan Osborn’s 46% among likely voters in recent New York Times/Siena polling, which found Osborn pulling 16% of those who said they’re voting for Trump and 63% of independents. Because Nebraska splits its electoral votes by congressional district, the national attention on the competitive Omaha-based 2nd District may also be making things harder for Fischer and her GOP allies, who’ve been outspent by Osborn and a supportive super PAC.

The late spending from the NRSC and the Senate Leadership Fund is a sign that Republicans aren’t comfortable with where the senator stands. Still, in a state that’s so red overall – Trump won it by 19 points in 2020 – Fischer has the advantage.

But Osborn, a former union president, is making an anti-establishment argument against Fischer, who was first elected in 2012. His ads feature Republican farmers slamming the senator as a “fake rancher and fake conservative.” Trying to drive home his outsider bona fides and connect to voters’ exhaustion with attack ads, Osborn blowtorches a TV in another spot. “This is why normal people don’t run for office,” he says. “This makes you want to cut your TV in half.”

Republicans, meanwhile, are trying to tie him to Harris and Vermont Sen. Bernie Sanders. The question in the final days is how much that late GOP spending is able to shore up Fischer’s position and knock down Osborn.

CNN’s David Wright contributed to this report.

The-CNN-Wire
™ & © 2024 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.