What did Mitt Romney say about Donald Trump?

Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks during a campaign stop at Lansing Community College May 8, 2012 in Lansing, Michigan. (Getty Images)

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Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks during a campaign stop at Lansing Community College May 8, 2012 in Lansing, Michigan. (Getty Images)

Mitt Romney took to a microphone Thursday to denounce GOP front-runner Donald Trump and urge Republicans to choose anyone but the New York billionaire as the party's nominee.

In a 20-minute speech, Romney said Trump is a phony, is unstable and is a braggart.

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While not endorsing any other candidate, Romney did suggest that anyone in the race other than Trump would be a good bet.

"The only serious policy proposals that deal with the broad range of national challenges we confront today, come from Ted Cruz, Marco Rubio, and John Kasich," Romney said of Trump's GOP rivals. "One of these men should be our nominee."

Here are a few of the things Romeny said of Trump  Thursday:

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

“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.”

“His promises are as worthless as a degree from Trump university.”

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

“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.”

“I am far from the first to conclude that Donald Trump lacks the temperament of be president. After all, 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.”

"Watch, by the way, how he reacts to my speech today. Will he talk about our policy differences or attack me with every low road insult?"

“There’s plenty of evidence that Mr. Trump is a conman, a fake.”

Romney also attacked Hillary Clinton:

“For the last 3 decades the Clintons have lived at the intersection of money and power. They embody the phrase Crony Capitalism.”

Reaction came quickly:

From John Kasich:

 From John McCain:

Before the speech, Trump mocked Romney on Twitter as a "failed candidate" who should not advise on electability:

Hours later, as Trump spoke  before a crowd in Maine, he called Romney "a choke artist" who lost to Barack Obama because he was a poor candidate, and said Romney begged him for an endorsement in 2012 race.

"I could have said, 'Mitt, drop to your knees.' He would have dropped to his knees," Trump said.