HARRISBURG, Pa. (WPVI) — The Pennsylvania U.S. Senate race between three-term Democratic Sen. Bob Casey and Republican challenger David McCormick could help Republicans fill their newfound majority in the chamber in the battleground state contest that is one of the nation’s most expensive races this year.

McCormick led the vote count by nearly 100,000 votes, or 2%, early Wednesday morning, but a significant portion of the votes remained uncounted.

At an election night party at a hotel in Casey’s hometown of Scranton, Mayor Paige Cognetti, a Casey ally, expressed confidence that Casey would ultimately win after all the votes were counted. But he told partygoers to go home just before midnight in the hope that the result would be clear on Wednesday.

Casey, perhaps Pennsylvania’s best-known politician and the son of a former two-term governor, appears to be seeking a fourth term after facing what he calls his toughest reelection challenge yet. Casey, 64, is a stalwart of the state Democratic Party and has won six statewide elections since 1996, including for the state’s auditor general and treasurer.

McCormick, 59, narrowly lost to Dr. in the 2022 Republican primary. After losing to Mehmet Öz, he ran for the Senate for the second time. He left his post as CEO of the world’s largest hedge fund after serving at the highest levels of former President George W. Bush’s administration and serving on Trump’s Defense Advisory Board.

The race ran on national themes, from abortion rights to inflation. But he also targeted local ones, like Casey’s accusation that McCormick was a wealthy carpetbagger from Connecticut’s swanky “Gold Coast.” Senate seat.

Casey also attacked McCormick’s hedge fund days, accusing him of getting rich at America’s expense by investing in Chinese companies that produce fentanyl and build Beijing’s military.

McCormick, for his part, emphasized his seventh-generation roots in Pennsylvania, recounting his high school days spent wrestling in towns in northern Pennsylvania, a sport that took him to the US military academy at West Point, and his time running online auction house FreeMarkets Inc. ., bore his name on a skyscraper in Pittsburgh during the tech boom.

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A staunch ally of labor unions and President Joe Biden, Casey campaigned on protecting the middle class, abortion rights, workers’ rights and voting rights, and said McCormick and former President Donald Trump were a threat to all of them.

McCormick, on the other hand, accused Casey of blaming the Biden administration’s border, economic, energy and national security policies for inflation, civil unrest and war. He attacked Casey as a weak, out-of-touch career politician and took it for granted that he would align himself with Vice President Kamala Harris if he became president.

Democrats currently hold a narrow majority in the Senate.

Both Casey and McCormick were unopposed for their party’s nominations in the primaries.

The Nov. 5 Senate vote also includes John Thomas of the Libertarian Party, Leila Hazou of the Green Party and Marty Selker of the Constitution Party.