Mitt Romney's Epic Trump Take-Down: 'He's a Phony!'

Former Republican presidential nominee Mitt Romney spoke out in an epic take-down of Republican frontrunner Donald Trump, calling him a "phony" and rallying Republicans around the country to stand against him.

"Here's what I know: Donald Trump is a phony, a fraud; his promises are as worthless as a degree from Trump University," Romney said in a speech to a University of Utah audience.

CBN News Senior Political Correspondent David Brody gives his take on Romney's speech and Trump's response. Click play to watch.

Romney has commented on Trump a few times over the past few days, but nothing as forceful as his statements Thursday.

"Let me put it plainly: if we Republicans choose Donald Trump as our nominee, the prospects for a safe and prosperous future are greatly diminished," warned Romney. "He gets a free ride to the White House, and all we get is a lousy hat."

Romney called on Republicans in states yet to vote in primaries or caucuses to extend their support to the other three remaining candidates. Specifically, he asked voters to support whichever candidate they believe has the best chance of defeating Trump in their home states. 

"I believe we can nominate a person who can win the general election and who will represent the values and policies of conservatism," said Romney.

"Given the current delegate selection process," he continued, "this means that I would vote for Marco Rubio in Florida, for John Kasich in Ohio, and for Ted Cruz or whichever one of the other two contenders has the best chance of beating Mr. Trump in a given state. One of these men should be our nominee..."

Watch what Romney had to say about a potential Trump nomination.

Click below to see Trump's response from the campaign trail in Maine.

Frantic GOP leaders say they still have options for preventing Trump from winning the nomination, but not many they're confident in.

Romney says a Trump nomination would almost guarantee a victory for Hillary Clinton in the general election.

"A person so untrustworthy and dishonest as Hillary Clinton must not become president. But a Trump nomination enables her victory," he said.

Romney says Trump "has neither the temperament nor the judgment to be president."

"This is an individual who mocked a disabled reporter, who attributed a reporter's questions to her menstrual cycle, who mocked a brilliant rival who happened to be a woman due to her appearance, who bragged about his marital affairs, and who laces his public speeches with vulgarity," said the former Massachusetts governor.

Romney also questioned if Trump truly is the smart businessman he claims to be.

"But wait, you say, isn't he a huge business success that knows what he's talking about? No he isn't...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.

Romney argues that Trump's "domestic policies would lead to recession and that his foreign policies would make America and the world less safe."

"His personal qualities would mean that America would cease to be a shining city on a hill," he warned.

"Donald Trump tells us that he is very, very smart. I'm afraid that when it comes to foreign policy he is very, very not smart," Romney insisted. "The only serious policy proposals that deal with the broad range of national challenges we confront, come today from Ted Cruz, Marco Rubio, and John Kasich."

Trump will give an official response at 1:30 p.m., but in true Trump fashion, the Twitter rant has long since begun.

"Just another desperate move by the man who should have easily beaten Barrack Obama," said Trump on Twitter. "Why can't the leaders of the Republican Party see that I am bringing in new voters by the millions - we are creating a larger, stronger party!"