Days before his South Carolina primary, a G.O.P. congressman who voted to impeach Trump stands by his vote.

For New York’s beleaguered Republican Party, all signs had been pointing for months toward 2022 being an exceptional year.

As Democrats battle the traditional midterm slump, Republicans were blessed with unforeseen fortune, including a court victory that resulted in new congressional lines pitting veteran liberals against each other and putting new House districts in play. Add in Gov. Kathy Hochul’s middling poll numbers, and many New York conservatives were dreaming of a united G.O.P. winning its first statewide election since 2002.

Then Carl Paladino walked in.

Mr. Paladino, the party’s lightning rod former gubernatorial nominee, unexpectedly re-emerged in the past week as a candidate in the newly drawn 23rd Congressional District in Western New York, a development that has driven a sharp wedge between some Republicans, including those who feel Mr. Paladino’s history of racist and outrageous remarks disqualifies him and could endanger Republicans up and down the ballot.

It is also fueling a potentially nasty proxy war between two of the party’s younger Trump-aligned leaders vying for dominance: Representative Elise Stefanik, the powerful North Country conservative who has endorsed Mr. Paladino, and Nick Langworthy, the state party chairman who formally declared his candidacy for the 23rd District on Friday, taking a veiled swipe at his onetime ally’s tendency toward incendiary statements.

“We don’t just need people who like to make noise,” said Mr. Langworthy, in a campaign announcement video. “We need proven fighters who know how to win.”

Far from rattled, Ms. Stefanik, the No. 3 House Republican, is standing by Mr. Paladino, whom she endorsed moments after the district’s current congressman, Representative Chris Jacobs, announced last week that he would not seek re-election in the face of furious backlash for his embrace of gun control measures after mass shootings in Buffalo — near his district — and in Uvalde, Texas.

Representative Elise Stefanik, a member of House Republican leadership, has endorsed Mr. Paladino and is helping him qualify for the ballot.Credit…T.J. Kirkpatrick for The New York Times

Ms. Stefanik’s team spent the week helping Mr. Paladino collect signatures to qualify for the ballot. And privately, she and her allies are fanning discontent for Mr. Langworthy among midlevel party leaders and lawmakers, a growing number of whom believe his congressional run could prove a costly distraction for the party if he does not resign as chairman.

Needless to say, a rough-and-tumble primary battle on the banks of Lake Erie is not what Republicans had in mind ahead of critical midterm elections that were shaping up to be the most promising for the party in two decades.

After the redistricting fiasco for Democrats, party leaders planned to compete seriously in as many as a dozen House districts across the state.

And in a likely race for the governorship against Ms. Hochul, a Democrat who has seen her job performance ratings sag in the face of concerns about crime and the economy, Republicans are hoping for a serious shot at breaking a lengthy losing streak in a state in which registered Democrats outnumber Republicans by more than two to one.

Four Republicans are facing off in the June 28 primary for governor, with Representative Lee M. Zeldin of Long Island receiving the party’s blessing. Andrew Giuliani, the son of the former New York City mayor; Rob Astorino, the former Westchester County executive; and Harry Wilson, a corporate turnout expert, are also all on the ballot and will meet for their first debate on Monday.

“This is a distraction in a battle that nobody needs at all,” Thomas Doherty, a former top aide to Gov. George Pataki, the last Republican elected statewide in New York, said about Mr. Paladino and the debris spinning off his campaign.

“You have the leading Republican in the House supporting a guy who has a ton of baggage against the Republican chairman,” Mr. Doherty added. “It just doesn’t make any sense.”

Since Mr. Paladino entered the race last Friday, Media Matters, the left-leaning watchdog group, has already unearthed a Facebook post amplifying conspiracy theories about the mass shootings in Buffalo and Texas and a 2021 radio interview in which Mr. Paladino praised Adolf Hitler as “the kind of leader we need today.”

Mr. Paladino, 75, who was soundly defeated in the governor’s race by Andrew M. Cuomo in 2010, has long been known for racist and homophobic comments. He partially apologized for the Hitler remarks on Thursday, calling them a “serious mistake” that he nonetheless claimed had been twisted by the news media.

On Friday, Mr. Paladino’s campaign said it would not comment on Mr. Langworthy’s candidacy, but it said he planned to file more than 3,000 petition signatures to qualify for the ballot, more than his opponent.

“I am so grateful for the outpouring of grass-roots support from thousands of Republicans across NY-23 in such a short amount of time,” Mr. Paladino said in a statement. “Onward to victory!”

In her own statement, Ms. Stefanik said she was “focused on winning back the majority this November,” while serving her constituents and the House Republican Conference she leads in Washington.

But some Republican state leaders were apoplectic about Mr. Paladino, including Keith H. Wofford, a Black corporate lawyer who was the party’s 2018 nominee for attorney general. He issued an unsparing statement on Friday saying that his personal experience left no room for doubt about who Mr. Paladino was.

“There are many times where people have called one Republican or another a racist, and I have explained to those accusers why they were wrong,” Mr. Wofford said. “But Carl Paladino is a racist. Not ‘racially insensitive’; not ‘unsophisticated’; a straight-up, old-school racist.”

He added: “If he wins the primary, I hope he loses in November.”

Democrats have chosen Max Della Pia, an Air Force veteran and community activist, as their nominee in the district.

Nick Langworthy, who chairs the New York State Republican Party, is running against Mr. Paladino in a House primary. “We don’t just need people who like to make noise,” he said in a video announcing his candidacy.Credit…Johnny Milano for The New York Times

Mr. Langworthy’s decision to run — after he pushed Mr. Jacobs to step aside — has not been without controversy. A series of county party leaders have criticized him for trying to run for Congress and lead the state party simultaneously, raising concerns about conflicts of interest.

“It has to be all hands on deck and our state chair can’t be hunkered down in the 23rd Congressional District running a primary while we are simultaneously trying to elect a governor,” said Lawrence A. Garvey, the party chairman in Rockland County.

He called on Mr. Langworthy to resign.

“The potential is very much there to squander what good options we have this year,” Mr. Garvey added, clarifying that he was not trying to boost Mr. Paladino either: “No person in their right mind could defend some of the things he has said.”

That sentiment was echoed by Susan McNeil, the Republican Party chair in Fulton County, northwest of Albany, and Mike Rendino, her counterpart in the Bronx.

“You can’t serve two masters,” said Ms. McNeil, who is close with Ms. Stefanik. “I’m not arrogant enough to think I could do both.”

Mr. Rendino said Mr. Langworthy would make a fine congressman, but said “we need a state chair committed to raising the money necessary for ballot security and protecting the party in the upcoming statewide elections.”

In an interview, Mr. Langworthy, 41, argued that he was advancing the party’s interests by taking on Mr. Paladino and said that he maintained the support of the “vast majority” of county G.O.P. chairs in the state.

He also predicted he would have no trouble focusing on winning the governor’s race for Republicans in the general election after defeating Mr. Paladino in the primary.

“There’s naysayers and people who have self-interest in any organization, and perhaps they are egged on by certain elected officials, but I won’t take the bait,” he said. “The most destructive thing that can happen is for us to have a leadership election.”

Mr. Langworthy’s run for office comes after a career as a party operative, including a stint in Mr. Pataki’s office and time spent working for two Republican House members. In 2010, he became the chairman of the Erie County G.O.P., a position he used to boost Mr. Paladino’s raw and rambunctious campaign for governor.

Both he and Mr. Paladino urged Donald J. Trump to run for governor against Mr. Cuomo in 2013, ultimately failing to convince him. Both stumped for Mr. Trump in his 2016 presidential run.

In 2019, Mr. Langworthy helped oust the party’s longtime chairman, Edward F. Cox, with the then-president’s support and took the job himself, promising a new face for the party.

The 23rd District, which was redrawn by a court-appointed mapmaker last month, should be safely Republican. It runs from the Buffalo suburbs to the Southern Tier, on the New York-Pennsylvania border, and includes some of the state’s most conservative counties.

Still, after suffering a brutal spring — with their carefully crafted redistricting plan shredded by the courts and their lieutenant governor indicted on bribery charges — Democrats seemed delighted on Friday to sit back and let the Republicans share the glare of scrutiny.

“I would not call the past few months perfect for my team, and it worried me as a Democrat,” said Christine C. Quinn, a state party leader.

But she called the G.O.P. strife an ongoing “train wreck.”

“Republicans seem committed to messing this thing up so badly,” she added.