At a rally in Manheim, Pa., Oct. 1, Republican presidential nominee Donald Trump mocked Democratic rival Hillary Clinton stumbling during a 9/11 ceremony after she had been diagnosed with pneumonia. "She's supposed to fight all these different things, and she can't make it 15 feet to her car," Trump said. (The Washington Post)

At a rally in Manheim, Pa., Oct. 1, Republican presidential nominee Donald Trump mocked Democratic rival Hillary Clinton stumbling during a 9/11 ceremony after she had been diagnosed with pneumonia. "She's supposed to fight all these different things, and she can't make it 15 feet to her car," Trump said. (The Washington Post)

Republican leaders and strategists are unnerved by Donald Trump’s erratic attacks on a Latina beauty queen and other outbursts this week, increasingly fearful that the GOP nominee is damaging his White House hopes and doing lasting harm to the party in the campaign’s final stretch.

Party officials said they are newly embarrassed by Trump’s impulsive behavior and exasperated by his inability to concentrate on his change message and frame the race as a referendum on Democratic nominee Hillary Clinton, according to interviews with more than two dozen of them.

Senate and House candidates are ducking questions about Trump and distancing themselves, while Senate Majority Leader Mitch McConnell (R-Ky.) has refused to talk about him. And few elected leaders are counseling him.

“Maybe every two weeks,” House Speaker Paul D. Ryan (R-Wis.) said to a business crowd about how often he speaks with Trump.

Trump went into the first presidential debate Monday night in Hempstead, N.Y., with swagger, ahead or tied in some national and battleground-state polls and, momentarily at least, relatively disciplined on the stump. But his performance was widely panned and revealed his thin skin. In the days since, he has become distracted by old grudges and picked new fights, often involving female or minority targets.

At a rally in Coral Springs, Fla., Sept. 30, Democratic presidential nominee Hillary Clinton attacked her opponent Donald Trump for tweets he sent out in the early hours of the night before. (The Washington Post)

Trump plunged into a feud with Alicia Machado, a Miss Universe winner he mocked and humiliated for her weight gain two decades ago. He punctuated his campaign to discredit her with a series of tweets around 5 a.m. Friday maligning her and referring his followers to Machado’s “sex tape.” There is no evidence that such a tape exists; he appears to have been referring to racy footage of her from a reality television show.

Also this week, Trump raised former president Bill Clinton’s past extramarital affairs as a campaign issue, delivered his most direct attack yet on Hillary Clinton’s health and waged war with news organizations over alleged bias.

[Trump stirs old Clinton sex scandals, to the dismay of some allies]

Reflecting upon Trump’s actions, Matt Borges, the Republican Party chairman in battleground Ohio, said, “Can this thing just end — please?”

“My God,” he sighed, “what a nightmare.”

Borges said he has personally urged Trump to run “a very disciplined, different kind of campaign,” although he remains confident that Trump will carry Ohio regardless.

Former Virginia congressman Thomas M. Davis, for decades one of the GOP’s top national campaign tacticians, said there is mounting concern that Trump’s lack of restraint is an anchor on him and the party.

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“You’ve got the nomination of the party, and you’ve got a certain responsibility to the party to try to win this thing, but he gets sidetracked very easily,” Davis said. “He goes off on personal vendettas, and it’s just not helpful if you want to win. The tragedy is he has every opportunity to win.”

Polls show Clinton beginning to pull away in several states, with seven-point leads in the latest polls from Michigan and New Hampshire, and ticking up in national surveys. A Fox News national poll released Friday showed Clinton ahead of Trump 43 percent to 40 percent in a four-way race.

In private conversations this week, Trump’s high command has sought to reassure party figures, including Senate and House leaders, that there is no reason to be alarmed by the debate or by Trump’s ensuing theatrics, explaining them away as part of his appeal to the masses.

Publicly, the candidate’s top allies angrily batted away all criticism and said they consider it a betrayal of the nominee. Former New York mayor Rudolph W. Giuliani, a confidant of Trump’s who spent much of the week traveling at the candidate’s side, blasted fellow Republicans for widespread disunity that he does not see in the rival party.

“Republicans are a bunch of frightened rabbits,” Giuliani said. “Unfortunately, we have a party made up of a bunch of people who get frightened very easily, and their hands start to shake whenever something happens that they don’t like.”

[Donald Trump’s weight problem: He can’t stop talking about ‘fat’ people]

Jason Miller, a senior adviser on Trump’s campaign, said, “There’s always going to be some degree of Beltway chatter, no matter how perfectly things are going.”

But, he added: “I think the party will be very united going into November because of the desire to beat Hillary Clinton and elect a true agent of change like Donald Trump. Mr. Trump is always going to be his own most effective spokesperson.”

The Republican National Committee, chaired by Reince Priebus, remains one of Trump’s staunchest boosters within the party, with its strategist Sean Spicer working many days from Trump Tower in New York and Priebus joining Trump for fundraisers and rallies.

But as members of Congress prepared this week to disperse to their home states for the remainder of the campaign, there was an acute sense of anxiety about Trump on Capitol Hill.

At an intimate fundraiser Wednesday for Rep. Joseph J. Heck (R-Nev.), who is running for the Senate, McConnell asked the group of about a dozen supporters how many of them think Trump can win. About half of the attendees raised their hands. But when McConnell then asked how many thought Trump would win, no hands went up, and the room fell silent, according to a person familiar with the scene who spoke on the condition of anonymity to discuss a closed event.

[Trump’s attacks on her weight are a ‘bad dream’ for former Miss Universe]

Few Republicans were keen on discussing Trump’s debate performance or defending the personal dramas he has reignited. McConnell bluntly swept aside questions about Trump.

“This is not something that I am going to discuss today,” the Senate leader told one reporter who asked about Trump’s impact on Senate races.

Pressed by another reporter about why he would not speak about Trump, McConnell replied, “Because I choose not to.”

When Ryan was asked to comment on Trump’s attacks Tuesday on Machado, the Wisconsin Republican demurred: “I was working out and working this morning. I didn’t watch.”

Embattled GOP senators found various ways to avoid evaluating Trump’s debate turn.

“I didn’t see it, guys. I was on an airplane,” Florida’s Marco Rubio told reporters.

“I have no idea. I’m not a pundit,” Wisconsin’s Ron Johnson said.

“I think he did fine, and I look forward to watching the next debate,” New Hampshire’s Kelly Ayotte said.

Terry Sullivan, a veteran GOP consultant who managed Rubio’s presidential campaign, said: “He’s definitely hurting the party if for no other reason than these candidates keep getting asked about stupid Trump crap. At best, he is a distraction for these candidates — and at worst, he’s a huge drag on the ticket.”

Some of Trump’s most ardent defenders said after the debate that he ought to turn his attention to the issues that will affect the country and show he can govern effectively, not become stuck in quarrels.

“When Hillary lays traps, or the moderator asks questions, get it focused,” Rep. Tom Reed (R-N.Y.) said as he left a weekly meeting of loyal Trump backers this week. “Get it focused on what really moves the needle in regards to how you deliver your message and vision for the American people.”

[Ivanka Trump stars in new ad to help her father appeal to women]

Still, Trump dug in on Machado, creating discomfort for fellow Republican politicians. On Friday morning, when Rep. John L. Mica was asked on MSNBC about Trump’s tweets lashing out at her and calling her “disgusting,” the Florida Republican said awkwardly, “I don’t tweet, and I don’t retweet.”

Former Virginia governor Jim Gilmore, a Trump supporter and former Republican National Committee chairman, refused in an interview Friday to answer questions about Trump’s Machado feud.

“I won’t engage the discussion,” Gilmore said. “It’s outside of what the main focus of the campaign should be, a diversion created by the Democrats and the media. I would not address the lady at all, to you or anybody else.”

Robin Hayes, chairman of the Republican Party in North Carolina, a crucial battleground state for Trump, said the nominee must tether his pitch to his promise to disrupt Washington and make the case against Clinton’s judgment.

“I don’t mean to be a critic, but a coaching tip would be, ‘Stay on the message and drive it home,’ ” Hayes said. “Whatever the other stuff is, it doesn’t matter.”

Among Trump’s backers on Capitol Hill, there is an acceptance of Trump’s style, even if it makes them anxious.

“Donald Trump is Donald Trump,” Rep. Peter T. King (R-N.Y.) said. “The reality is he’s operating in a separate world from politicians, the rest of us. He gets away with things no one else would. People are willing to accept someone who’s not close to being perfect because of the anti-establishment mood.”

Rep. Jason Chaffetz (R-Utah) said, “I’m sure there are some nervous Nellies, but he seems to win, and win big.”