Everything You Need to Know About Thursday's Fox News GOP Debate

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In a speech at University of Utah today, Mitt Romney called Donald Trump a "phony" and a "fraud."

The 2012 GOP nominee argued that Trump, if nominated, would enable Hillary Clinton to be elected president; and that his policies, if implemented, would sink the country into a prolonged recession.

The former Massachusetts governor slammed the frontrunner's business acumen, saying that he is not the business genius he purports to be.

"But wait, you say, isn't he a huge business success that knows what he's talking about? No he isn't, and no he doesn't. His bankruptcies have crushed small businesses and the men and women who worked for them. He inherited his business, he didn't create it. And what ever 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."

He also criticized Trump's temperament and said that "dishonesty is Trump's hallmark."

"His is not the temperament of a stable, thoughtful leader. His imagination must not be married to real power."

Romney concluded: "Donald Trump is a phony, a fraud. His promises are as worthless as a degree from Trump University. He's playing the American public for suckers: He gets a free ride to the White House and all we get is a lousy hat.

“His domestic policies would lead to recession. His foreign policies would make America and the world less safe,” Romney is expected to say. “He has neither the temperament nor the judgment to be president. And his personal qualities would mean that America would cease to be a shining city on a hill.

"America has greatness ahead. This is a time for choosing. God bless us to choose a nominee who will make that vision a reality."

Watch the full speech above.

Meanwhile, Trump has been hitting back against the 2012 GOP nominee on Twitter.

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