To avoid costly Senate battleground defeats in 2024, Republicans have a plan: run like Democrats.

That means trying to replicate Democrats’ success at avoiding the kinds of vicious intraparty battles that have weakened Republican nominees in recent years.

It remains to be seen whether the party’s attempt to sidestep fault lines between Trumpian loyalists and traditional conservatives will be effective, but the strategy’s first victory could come in Pennsylvania, where David McCormick appears to have cleared the Republican primary field of any major challengers.

Mr. McCormick — a former hedge fund executive who lost one of the party’s nastiest and most expensive Senate primaries to Dr. Mehmet Oz last year — will announce his new campaign on Thursday evening in Pittsburgh. He is aiming to unseat Senator Bob Casey, a Democrat who has announced plans to seek a fourth six-year term in office.

Senate Republicans have begun similar efforts to clear the path for Gov. Jim Justice in West Virginia, where Senator Joe Manchin III, a Democrat, is weighing a re-election bid. Mr. Justice, however, faces a primary fight against Representative Alex Mooney, who has vowed to oppose the “establishment swamp.”

In Montana, Senator Steve Daines, who is the chairman of Senate Republicans’ campaign arm, has endorsed Tim Sheehy’s bid to take on Senator Jon Tester, the incumbent Democrat. But Mr. Sheehy, a wealthy businessman and military veteran, could face a primary challenge from Representative Matt Rosendale, who lost to Mr. Tester in 2018 and said last month that Montanans should decide the race, “not Mitch McConnell and the D.C. cartel.”

But in Pennsylvania, Mr. McCormick appears to have assuaged concerns from the right. One of his competitors in the Senate primary race last year, Kathy Barnette, is working for Vivek Ramaswamy’s 2024 presidential bid.

And crucially, Doug Mastriano, a far-right state senator who was viewed as a potential Senate candidate from the Trumpian wing of the party, has declined to run.

Mr. Mastriano appeared on the verge of endorsing Mr. McCormick after meeting with him and his wife, Dina Powell, a former Goldman Sachs executive who served in the Bush and Trump administrations. During their meeting, the two men found common ground over their military service, according to two McCormick allies familiar with the conversation.

Still, Mr. McCormick’s ability to avoid a primary — at least so far — does not necessarily signal a new willingness by Republicans to put aside their differences.

Instead, the lack of a serious contender may stem from Mr. McCormick’s continued politicking in Pennsylvania, and a reluctance from others to take on the enormous challenge of unseating an incumbent.

Pennsylvania Democrats argue that President Biden’s unpopularity will not be as much of a problem in their state. Mr. Biden has already traveled to Pennsylvania at least nine times this year, and Mr. Casey has greeted him at several of those stops. Mr. Casey helped John Fetterman and Josh Shapiro campaign in their successful bids for Senate and governor last year, and aides to both men said they were eager to return the favor.

The race last year to replace the retiring Senator Patrick J. Toomey ended up costing more than $360 million, according to OpenSecrets, a nonpartisan group. Similar amounts could be spent in 2024, when Pennsylvania — unlike Montana and West Virginia — will double as a top battleground in the presidential race.

Mr. McCormick will be able to bring his own financial firepower to the race: He earned a salary of more than $22 million at his most recent job and listed assets worth between $116 million and $290 million on his candidate financial disclosure last year.

Still, many Republicans contend that Pennsylvania is not among the three states where the party has the best chance to win back a majority that has eluded them since 2021. Republicans’ clearest opportunities to flip seats appear to be in Montana, Ohio and West Virginia, all of which Donald J. Trump easily won in 2020.

But Mr. McConnell, the Senate Republican leader, raised eyebrows this year when he added Pennsylvania to his list of top priorities. Some Republicans involved in efforts to recruit Senate candidates have privately wondered whether Mr. McConnell’s statement was meant to help persuade Mr. McCormick to enter the race.

“Dave has the guts — and the money — to run,” said Doug McLinko, a county commissioner in Bradford County who describes himself as a “hard-core Republican on ballot security” and a Trump loyalist.

Mr. McLinko did not support Mr. McCormick in the 2022 race but said he would next year because he had gotten to know the businessman.

Even after losing the primary last year, Mr. McCormick helped Pennsylvania Republicans campaign and raise money for the general election, and he has since continued those efforts.

His political committee, Pennsylvania Rising, has contributed more than $100,000 to conservative candidates and causes since last year. Multiple Republicans described Mr. McCormick as a ubiquitous presence at state party events since the 2022 election.

Jackie Kulback, the Republican chairwoman in Cambria County, said she was backing Mr. McCormick partly because her choice last year, Jeff Bartos, was not running, but also because she had been impressed by Mr. McCormick when he spoke at a recent event about his private-sector experience in China.

“I like to win and try to get behind winners,” Ms. Kulback said. “Not many have Dave McCormick’s résumé, and I just feel like he’s the whole package.”

Mr. Trump, who backed Dr. Oz last year, attacked Mr. McCormick over that same experience in China during the primary race and derided him as a globalist, which helped sink Mr. McCormick’s campaign.

The former president has not endorsed anyone in the Pennsylvania race this time. A campaign spokesman declined to comment.

Mr. McCormick lost the primary by fewer than 1,000 votes. He earned good will among some Pennsylvania Republicans by not pressing for a recount, said Sam DeMarco, the Allegheny County Republican chairman. Mr. DeMarco helped collect signatures from more than half of the state party’s 67 county chairs supporting Mr. McCormick’s candidacy.

“I’m tired of losing,” Mr. DeMarco said. “David is someone who can appeal to both sides of the party.”

Mr. McCormick was largely unknown in Pennsylvania political circles before last year, partly because he spent much of his adult life outside the state. Democrats are already attacking him over his residency, a strategy that helped torpedo Dr. Oz.

On Thursday, the Pennsylvania Democratic Party described Mr. McCormick in a news release as a “Wall Street mega-millionaire who is lying about living in Pennsylvania.”

Pennsylvania Democrats also criticized Mr. McCormick on Wednesday for deleting from his YouTube page a 2022 interview in which he said the Supreme Court’s decision to overturn Roe v. Wade was a “huge step forward and a huge victory for the protection of life.”

But McCormick’s allies insist he is ready to beat back residency questions and to appeal to suburban women — and other voters turned off by Mr. Trump’s brand of politics — by leaning on his private-sector experience and his personal background.

Mr. McCormick grew up in Bloomsburg, Pa., about an hour southwest of Scranton, Mr. Biden’s birthplace. He graduated from West Point, served five years in the Army — where he was awarded a Bronze Star for his service in the Persian Gulf war of 1991 — and earned a Ph.D. in international relations at Princeton.

He returned to Pennsylvania and joined FreeMarkets, a Pittsburgh-based internet auction company. After the company was sold in 2004, Mr. McCormick held multiple roles in the Bush administration.

In 2009, Mr. McCormick moved to the Northeast and joined Bridgewater Associates, a hedge fund in Westport, Conn., that manages $150 billion in assets. After becoming chief executive in 2017, he resigned in 2022 and turned his attention to a Senate campaign.

As much as Mr. McCormick may try to focus on issues, he will also have to answer questions about Mr. Trump and seek to satisfy the competing factions inside his own party.

“If anyone is drawing the conclusion that a clear path for McCormick is because fractures are gone and we’re all singing ‘Kumbaya,’ they’re sadly mistaken,” said Sam Faddis, who leads a coalition of right-wing activist groups in the state, adding that he liked Mr. McCormick but remained on the fence about his candidacy.

Mr. Faddis added, “The division between the grass roots and the establishment is massive in Pennsylvania, and massive nationwide.”