Mitt Romney leaves the funeral services for former senator Bob Bennett in Salt Lake City on May 14. (Scott Sommerdorf/Salt Lake Tribune via AP)

Mitt Romney warned that a Donald Trump presidency could normalize racism, misogyny and bigotry in the national conscience. Businesswoman Meg Whitman compared the presumptive Republican presidential nominee to Adolf Hitler. House Speaker Paul D. Ryan (R-Wis.) was asked, uncomfortably, how he could explain his endorsement of Trump to a young child.

Then came Trump’s boosters, awkwardly imploring about 300 business executives and GOP establishment donors and strategists gathered here for Romney’s annual ideas festival to unite for the fall campaign. In a stroke of defiance, Republican National Committee Chairman Reince Priebus declared that Trump and the GOP would win in November “with or without you,” according to attendees.

So went the three-day Romney-hosted E2 summit that concluded here Saturday in this luxurious mountaintop resort. The confab put on stark display the Republican Party’s moral and philosophical divisions over its new standard-bearer and underscored the difficulty that Trump and allies such as Priebus will have to consolidate forces at the start of a general election in which Democrat Hillary Clinton is favored.

[At Romney summit, anti-Trump Republicans in exile ponder party’s future]

Anthony Scaramucci, a New York financier who was one of Romney’s top funders in 2012, came to Park City seeking to galvanize his old friends to help him raise money for Trump. He likened the atmosphere here to the hit HBO series “Game of Thrones.”

Republican presidential candidate Donald Trump went after former Republican presidential nominee Mitt Romney who had suggested the billionaire was a racist. (Reuters)

“I feel like Jon Snow, trying to get the Wildlings to team up with the kings of the castles,” Scaramucci said.

Recalling what he told Romney loyalists, Scaramucci said: “Your father just got slayed by your uncle, whom you don’t really like, and your uncle is now in charge. You’ve got the White Walkers descending from the north and they’re coming to hunt you and all the living. What do you do? Do you fight with your uncle or band together and fight the White Walkers?”

Romney made clear he would rather fight his uncle, figuratively speaking. The 2012 GOP presidential nominee was emotional here Saturday as he delivered an impassioned case against Trump. He said the business mogul’s campaign rhetoric — the latest example being his accusations of bias by a federal judge because of his Mexican American heritage — is so destructive that it is fraying at the nation’s moral fabric and could lead to “trickle-down racism.”

“I love what this country is built upon, and its values — and seeing this is breaking my heart,” Romney told summit attendees, according to the Associated Press.

Trump punched back at Romney at his Saturday rally in Tampa, calling him “poor, sad, Mitt Romney” and a “stone-cold loser.”

Scaramucci and other Romney associates supportive of Trump, including Ron Kaufman, a longtime RNC member from Massachusetts, have pleaded with Romney to tone down his opposition in the interest of party unity.

“If Joseph Stalin and Franklin Roosevelt could get together to defeat Adolf Hitler, we can end the schism in our party,” Scaramucci said. “We’ve got to change the rhetoric and the nonsense that’s going on in the party right now. We have to unify this party.”

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Priebus, Scaramucci and restaurant executive Andy Puzder, another Romney ally raising money for Trump, were in Park City to try to build out Trump’s fundraising operation, which got off to a late start and has been slow to ramp up. They sought to allay worries about Trump’s discipline, electability and character — and even joked with prospects about overseas ambassadorships being available in a Trump administration.

Scaramucci said that summit attendees were “going nuts” about Trump’s attacks on Judge Gonzalo Curiel but that he told them privately: “I understand that sometimes when he’s speaking it can send a charge signal. But I’ve known him for two decades and I know his children. He is not a racist.”

While Romney spent nearly a decade cultivating relationships with party benefactors, Trump is only now trying to attract major financial support, after largely self-financing his primary campaign. It was not until this past week that Trump’s joint fundraising operation with the RNC had put together a full slate of finance events for June. By comparison, Romney had already raised $140 million in conjunction with the party by the end of June 2012.

Veteran fundraisers acknowledge that the Trump and RNC team has a dwindling amount of time to organize the kind of lavish events that are usually held to solicit six-figure checks, but the team is optimistic. Supporters think that Trump will attract a new cadre of wealthy figures he knows through his real estate developments who had never before given to the party.

[Ryan grilled at Romney summit as Meg Whitman compares Trump to Hitler]

Among Romney loyalists, however, the appeals from Trump’s team have had limited success.

“They would like to see a unified party, but if I hear anything consistently, it’s country before party,” said Spencer Zwick, a Romney confidant and his former national finance chairman, who helps run the E2 summit.

That was the argument Whitman, the chief executive of Hewlett-Packard, made when she questioned Ryan about his endorsement of Trump and compared the candidate to fascist leaders Hitler and Benito Mussolini, according to attendees.

Texas businessman L.E. Simmons, a close Romney friend who helped raise millions of dollars for his last campaign, said he was in no rush to decide whether to support Trump.

“He couldn’t have done a worse job in his first month” since securing enough delegates to claim the nomination, Simmons said of Trump. “I think he missed a golden opportunity to pivot. There’s a lot of people who really want it to work, but they’re not going to say, ‘Trump at any cost.’ ”

Dan Balz in Park City and Matea Gold in Washington contributed to this report.