The odds of Democrats hanging onto control of the Senate come 2025 are pretty slim, and all could hinge on if Vice President Kamala Harris defeats former President Donald Trump in the presidential election.
Republicans are poised to win Democratic Sen. Joe Manchin’s seat in West Virginia. If no other seats flip, and Trump wins the presidency, Republicans gain control of the Senate.
Even if Harris wins and Tim Walz becomes vice president, Republicans likely just need to win a Senate seat in states like Montana or Ohio to pick up a majority.
Recent polls show Republican Tim Sheehy ahead of Democratic incumbent Sen. Jon Tester in Montana. The Democratic incumbent in Ohio, Sen. Sherrod Brown, has held a very narrow lead in recent polls.
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Republicans are also within striking distance of taking seats in Michigan, Pennsylvania and Wisconsin, although most polls have Democrats ever so slightly ahead in those states.
The only Republican-held seat that Democrats could realistically win would be Sen. Ted Cruz’s seat in Texas, but that would likely mean that Democrats had a much better night than expected.
There is also an intriguing race in Nebraska that Democrats have no chance of winning, but could somehow factor in the balance of power.
Here are the seats to watch on Election Night:
Ohio
This is arguably the most competitive Senate race in the nation with polling showing a tight race between three-term incumbent Democrat Brown and businessman Bernie Moreno.
A poll by Bowling Green State University Democracy and Public Policy Research Network/YouGov showed Brown ahead by a 47-45 margin.
Brown was first elected in 2006 and won reelection in 2012 and 2018. All three years were considered good years for Democrats, and being a moderate in a relatively red state, Brown has managed to stay in the Senate for 18 years.
But Brown is more vulnerable than ever.
The race is the most expensive in the country when factoring outside spending. Between contributions for candidates and outside spending, there has been $387.6 million spent. According to Open Secrets, the candidates have garnered over $127 million in contributions, with Brown raising $89 million on his own.
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But outside spending has helped keep Moreno competitive. There has been $68 million being spent to support Moreno, and over $112 million spent to oppose Brown. Conversely, outside groups have spent over $22 million to support Brown and nearly $77 million to oppose Moreno.
Montana
As the campaign continues, this one has increasingly swung toward Sheehy. Like Brown, Tester has benefited from running in years favorable to Democrats.
It appears he is less likely to survive in a year not as favorable to the party. A recent Emerson College poll showed Sheehy up 51-48.
This race has also been among the most expensive in the U.S., according to Open Secrets. Tester, however, has a massive advantage in donations over Sheehy.
Pennsylvania
For the first time in four elections, it appears Sen. Bob Casey is in a competitive race. He faces former George W. Bush administration official David McCormick.
McCormick unsuccessfully ran for Senate in 2022, falling in the GOP primary to Mehmet Oz. While Casey has garnered more donations to his actual campaign, McCormick has a huge advantage in outside money being spent on his behalf. Groups have spent over $100 million running attacks against Casey.
The campaign has apparently worked. In recent weeks, Casey has seen his lead shrink to about three points in most polls.
This race could also serve as an important bellwether to Trump and Harris as the Senate race’s polling has resembled polling between the two presidential candidates.
Nebraska
Arguably the most intriguing race in the U.S. is in Nebraska. The Democrats have not endorsed a candidate in the race, but independent candidate Dan Osborn has led in several polls over Republican Sen. Deb Fischer. It's unknown if Osborn would caucus with either party, but his candidacy has added a wrinkle to this year's Senate race.
A recent New York Times poll showed Fischer up by two points, a shockingly close margin given that both Nebraska is a Republican-leaning state and that her opponent is an independent.
Technically, the Senate currently has four independent members, but all four caucus with Democrats. While it’s far from unprecedented for independent candidates to win Senate races, Osborn would be unique in not having any elected experience.
Two current Sens. Kyrsten Sinema and Manchin were elected as Democrats before leaving the party while in office. Maine Sen. Angus King was the state’s former governor while Vermont Sen. Bernie Sanders was mayor of Burlington.
Because of Osborn’s independence, the race hasn’t drawn the kind of fundraising haul a normal competitive race would garner. There has only been about $24 million in outside funds being spent on this race and the two candidates have raised a combined $16 million.
Texas
Sen. Ted Cruz is looking to hold onto his seat six years after defeating Beto O’Rourke by less than three points. The reliably red state has not elected a Democrat to the Senate since 1986 when Sen. Lloyd M. Bentsen, Jr. won reelection.
There has long been talk about demographic changes that would lead to Texas becoming more competitive, but so far, Republicans have not relinquished any power. Polling shows Cruz’s challenger Rep. Colin Allred, a former NFL linebacker who starred at Baylor, within four points.
Despite trailing, Democrats see an opportunity as Allred is the best-funded non-incumbent running this year, according to Open Secrets. Republicans are also spending significant resources to defend the seat. Cruz is the best-funded Republican Senate candidate this year.
Michigan and Wisconsin
These seats also cannot be ignored as Democrats are only leading these two seats by slim margins in recent polls. In Wisconsin, Sen. Tammy Baldwin is up against business Eric Hovde. A recent Marquette poll showed Baldwin's lead among likely voters down to just two points.
In Michigan, Democrat Elissa Slotkin is leading Republican Mike Rogers 46-45, according to a Washington Post poll of likely voters. Both candidates are looking for promotions out of the House of Representatives.
