Romney set the tone for the debate with his morning address at the University of Utah, where he methodically litigated the case against a Trump presidency.
"Donald Trump is a phony, a fraud," Romney said. "He's playing members of the American public for suckers."
Romney, himself a onetime business titan worth hundreds of millions of dollars, sought to rub away at Trump's golden sheen.
"His bankruptcies have crushed small businesses and the men and women who work for them," Romney said. "Whatever happened to Trump Airlines? How about Trump University? And then there's Trump magazine and Trump Vodka and Trump Steaks and Trump Mortgage. A business genius he is not."
Romney said the president helps define the values and principles of the United States for the world and sets an example for young Americans. He asked his audience of roughly 700 students and other guests to ponder Trump's "personal qualities": "The bullying, the greed, the showing off, the misogyny, the absurd third-grade theatrics."
Trump fired back with a verbal tirade a couple of hours later at his Maine rally. He bemoaned Romney's "nasty" critique and dismissed him as a "choke artist" who, in Trump's assessment, botched an easy chance to turn President Obama out of office.
Trump has won 10 of the first primaries and caucuses, including dominating this week's Super Tuesday contests, and has a significant lead in the race for Republican convention delegates.
But in a divided field, Trump still has fewer than half the delegates awarded so far. That leaves his opponents with a viable, if risky and destructive, strategy. The only way to stop Trump from winning the nomination may be to stop anyone from winning it - dividing up the delegates so that no one has a majority.
Then, the theory goes, the party would head into a chaotic convention - the first true "floor fight" for any party in decades - and hope that a candidate other than Trump emerges.
This is just the scenario Romney encouraged when he recommended that Floridians cast ballots for Rubio, Ohioans cast ballots for Kasich, and everywhere else, voters back the candidate best positioned to deny Trump a victory in that state.
It was unclear whether Romney's speech would move any voters away from Trump. It could have the effect of intensifying support for the rebellious outsider.
But within the Republican establishment, Romney's speech drew immediate and enthusiastic praise. Within minutes, McCain issued a statement effectively joining forces with Romney.
"I want Republican voters to pay close attention to what our party's most respected and knowledgeable leaders and national security experts are saying about Mr Trump, and to think long and hard about who they want to be our next Commander-in-Chief and leader of the free world," McCain said.
But not every member of the establishment was speaking out against Trump. Christie has been Trump's most visible endorser of late, standing stone-faced behind Trump at his victory event on Wednesday in Palm Beach. It has sparked mocking memes on social media and laughs on late-night television.
Christie addressed that at his news conference in Trenton yesterday.
"I want everyone to know for those who were concerned: I wasn't being held hostage, I wasn't upset. I wasn't angry. I wasn't despondent," said Christie, who ended his candidacy last month after a disappointing finish in New Hampshire.
- Bloomberg
