PARK CITY, Utah (AP) -- Donald Trump can be an effective president, and he's going to win with you or without you, Republican Chairman Reince Priebus told several hundred of the party's top donors and strategists Saturday.

Trump is setting a dangerous example for Americans by promoting "trickle-down racism," and the party must look beyond this presidential election to find its future, the 2012 nominee Mitt Romney told the same group later that morning.

Delivered within moments of each other at Romney's annual business and politics summit at a five-star ski resort, those opposite messages were enough to cause whiplash. That's a hazard of being a Republican this year, as the party struggles to figure out what to do with its controversial presumptive presidential nominee.

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Blinking back tears as he spoke, an impassioned Romney said many have asked him to get off his "high horse" and back Trump, seeing presumptive Democratic nominee Hillary Clinton as unacceptable. "Either choice is destructive," Romney said. "I love this country. I love the founders. I love what this country is built upon, and its values. And seeing this is breaking my heart."

Romney said he would not spend time campaigning for or against Trump and predicted 90 percent of Republicans would vote for Trump.

The attendees, about 300 of Romney's longtime donors and friends, provided a snapshot of the wide range of GOP sentiment about Trump. While most are eager to keep Clinton out of the White House, Trump keeps giving many of them pause, the latest example being his comments that a federal judge's Mexican heritage prevents him from fairly overseeing a lawsuit against him.

Behind closed doors at the summit, Hewlett Packard President Meg Whitman likened Trump to Mussolini and Hitler and suggested she might vote for Clinton. GOP strategists and vocal Trump skeptics Stuart Stevens, Ana Navarro and Kristen Soltis Anderson told attendees to brace for a Clinton White House because Trump doesn't appeal to growing voter blocs, including Latinos.

"It's very difficult to envision" how Trump can win, Anderson said in a rare on-the-record session.

House Speaker Paul Ryan squirmed as he was asked how he could support Trump after denouncing the candidate's comments about the judge. He demurred, as he did during Whitman's Trump tirade, saying his leadership position means he must convey the will of Republican representatives, not just his own.

Spencer Zwick, Romney's former finance chairman and the current one for Ryan, tried to navigate the complex terrain between the two men, the former presidential nominee and his running mate.

"I would love to see the Republican Party come together," Zwick said. "At the same time, with comments like the one Donald Trump have made recently, I don't subscribe to that type of rhetoric. And I'm not an elected official. I don't have to make an endorsement. There's no pressure."

Yet many Republicans at the summit want to find a way -- and some can't.

"For me to jump in, this pivot has to come. We're still in primary mode, I guess because it has a reality TV feel. But the pivot has to happen, and it's not," said John Rakolta Jr., a former fundraiser and family friend of Romney who lives in Michigan. "I'm an optimist by nature, and I keep hoping and hoping and hoping that there will be a reason to support him."

Lanhee Chen, Romney's former policy director, had been feeling the same way -- until recently.

"The last two weeks have given me serious doubts as to whether he could beat Hillary Clinton," said Chen, a research fellow at the Hoover Institution. He said he is particularly bothered by Trump's personal attacks on Romney, but also sees red flags in Trump's comments about the judge and seeming unwillingness to build out his campaign infrastructure.

And there were those now firmly on Team Trump. Anthony Scaramucci, a New York investor, and Andy Puzder, a California fast-food chain executive, shook the money trees for their candidate. "This is not a rabidly anti-Trump crowd," Scaramucci said. "If anything, people are trying to find ways to diplomatically support the candidate."

Puzder said potential donors left him feeling encouraged. He said he respected people, including Romney, who might not get there. His pitch on Trump was to stay positive, reminding anyone who would listen that Trump has great children, which says something about his character.

Most of the three-day conference's sessions were closed to reporters, but described in detail by multiple attendees. Called the Experts and Enthusiasts summit, the gathering is sponsored by Solamere Capital, a private equity firm co-founded by Zwick and one of Romney's sons.

Missing from the gathering was Trump himself; he has never been invited to speak to the Romney crowd. (Last year, half-a dozen presidential candidates attended, but Trump hadn't announced his bid and wasn't taken seriously by almost anyone in the party.)

Trump weighed in from afar, saying at a Saturday rally in Tampa that Romney is bitter because he's a failed presidential candidate who "choked like a dog."