Romney's condemnation, made here at the Stein Eriksen Lodge before hundreds of his donors and business partners, highlighted the ill will between the last two GOP nominees for president.
The former Massachusetts governor harshly criticized Republican candidates such as Ohio Gov. John Kasich and Texas Sen. Ted Cruz, as well as super PACs such as Jeb Bush's well-funded Right to Rise group, for not stopping Trump in the primary. The two candidates largely avoided attacking Trump for much of their campaigns. He made the comments before many of the individuals who had helped fund those very candidates.
"Ted Cruz was basically praising Donald Trump through the whole process until the very end," Romney told CNN's Wolf Blitzer, who was hosting the discussion. As for Kasich, "he was in well after the time there was no possible pathway to becoming the nominee."
Romney's broadsides were warmly received by many of his allies, earning a 21-second round of applause when he wondered aloud about the future of the GOP.
"I find this so troubling, and I know a lot of folks are saying, 'Mitt just get off your high horse on this and get behind the guy.' But these things are personal. 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. The 2012 nominee was visibly emotional and appeared to tear up when making the remarks.
Yet Romney still preached tolerance. He declined to criticize previous speakers, including House Speaker Paul Ryan and Republican National Committee Chairman Reince Priebus, who pitched Trump to the well-heeled crowd this weekend, and said he would not try and sway the GOP elites assembled here to abandon their nominee. And he recognized as legitimate the notion that some Republicans may choose to back Trump solely to prevent Hillary Clinton from appointing Supreme Court nominees, calling it a "darn good reason."
The day before, Romney had told Blitzer
in an interview that he worried about the moral fraying of society should Trump become the nominee: "I don't want to see trickle-down racism," he said.
And before the crowd here on Saturday, Romney used another former president as an example of how society is shaped by his example.
"Bill Clinton's dalliances in the White House affected the sexual inclinations and practices of a generation, and probably beyond," he said.
But Romney was also challenged by some questioners who were trying to whip up support for Trump. Romney has pledged to never support Trump, and many of his fund-raisers feel similarly.
"We've got to get behind him," one man implored the crowd. "These are the cards we've been dealt."
Romney was also pressed as to why he accepted the endorsement of Trump during his 2012 presidential run given Trump's zest for "birtherism," or the idea that President Barack Obama was not born into the United States and is thus ineligible to be president. Romney said he saw Trump's comments as "nutty" but not disqualifying.
Now, the pair are using one another as political foils, with Trump blasting his GOP predecessor. On Saturday in Tampa, Florida, he called Romney someone who "let us down" and writing on Twitter that Romney "choked like a dog."
The former Massachusetts governor brushed off the attacks.
"I have dogs. I don't know dogs choking," Romney said to laughs. "That's an insult that somehow doesn't work."
Romney did, though, express some regret over his failed 2012 campaign, saying that he, like Bush, had failed to connect his economic vision with average, middle-class voters. But for now, Romney said he was trying to remain focused on the future, though he has now ruled out serving in the next White House.
"Had there been a President Bush or a President (Marco) Rubio or a President (Scott) Walker, I might've been happy to be a part of their administration," Romney said.