Earlier in the day, Trump, 69, claimed that he was the only one who can defeat Clinton in the November presidential elections. You have now viewed your allowance of free articles.

"I wouldn't vote for Donald Trump, and I wouldn't vote for Hillary Clinton", Romney said. But the idea is still quite different than his pledge to support Trump if he becomes the party's nominee.

It started about the personal attacks Rubio has made on Trump.

Ted Cruz, Florida Sen.

"You're not going to stop the corruption and the cronyism by supporting someone who has used government power for private gain", Cruz said. On immigration policy, Trump said that he had changed his mind, and is interested in bringing in skilled workers from overseas.

The former governor said Trump's economic policy would be detrimental to the country.

Asked if he would support the Republican nominee if it's not him, Trump said, "Yes I will".

The bad blood among the candidates flowed freely.

Rubio on why he made a decision to insult Trump on the trail: "For the a year ago Donald Trump has mocked everybody with personal attacks". And you know what they say about men with small hands? Trump said. "And [Marco Rubio] referred to my hands, 'If they're small, something else must be small.' I guarantee you there's no problem".

His campaign took advantage of this to market #DumpTrump yoga trousers, calling the senator's joke "the moment of the night".

"I'm not playing to anyone's fantasies", Trump argued. Trump essentially acknowledged the flip-flopping, telling Kelly that he's flexible and that when he better understood these issues, he changed his position: "I've never seen a successful person who wasn't flexible, who didn't have a certain degree of flexibility.... If somebody tells them something, can they believe it?"

As for Texas Sen.

The Detroit debate was one more opportunity for Rubio and Cruz to try to slow Trump's momentum.

"So I would like to take that back", Trump said.

Donald Trump is preparing to face his biggest rival for airtime in Thursday night's debate.

Cruz demanded Trump release an audiotape of an off-the-record session he had with New York Times editorial writers on January 5.

"He's trying to do to the American voters what he did to the people that signed up for this course", Rubio declared.

Republican front runner and billionaire real estate mogul Donald Trump defended his previous comments calling for the killing of innocent family members of Islamic terrorists. "It's a minor civil case!" I will give it to you tomorrow.

Trump called Rubio a "con artist" for missing a lot of Senate votes.

Romney readily conceded that he's out to prevent Trump from winning a majority of delegates in the primaries, so that Republicans can replace him as their nominee at their convention in July.

Trump swung back at the moderators-three times interrupting a question from Megyn Kelly about his now-defunct Trump University with a derisive "give me a break"-and at Cruz and Rubio, whom he nicknamed "Lyin' Ted" and "Little Marco".