Rubio, Cruz throw everything they can at front-runner Trump

Marco RubioMarco RubioObama plans 'aggressive' blitz for Clinton in campaign's final days One way or another, 2016 was all about Donald Trump's hands Poll: Clinton has 4-point lead over Trump in Florida MORE and Ted CruzTed CruzDemocrats pounce on Cruz's Supreme Court comments Brent Budowsky: An epic battle for the future of Congress Cruz: Precedent exists for keeping Supreme Court short-staffed MORE threw everything they had at Donald TrumpDonald TrumpThird-party candidate McMullin: We can win Idaho and Wyoming Pence's plane skids off runway in New York Trump lashes out over 'illegal' Access Hollywood tapes MORE at Thursday night’s Republican debate, hoping to find some way to stop the clear front-runner for the party’s presidential nomination.

Rubio in particular came out hot, seemingly dumping his opposition research on Trump as he attacked the billionaire on his eponymous university, his business record and his core political beliefs.

Trump, for his part, mostly kept his cool through the two-hour debate in Houston even as he was the focus of relentless attacks from Cruz and Rubio.

Both Cuban-American senators are trailing Trump badly in the delegate race, and need to do something fast to turn around the race.

A dozen states and U.S. territories will hold contests on Tuesday in the biggest day of the primary yet. Trump is leading polls in a majority of states, and has dominated the last three contests, in New Hampshire, South Carolina and Nevada.

As a result, Cruz and Rubio were desperate on Thursday to take Trump down a peg. The front-runner, for his part, dished out a series of counter-attacks while repeatedly returning to a singular theme: that he was the one non-politician on the stage who could provide answers for the nation.

He also largely dialed back his stage presence, seemingly content to run out the clock and protect his lead.

Rubio had the best attack line of the night while badgering Trump about his plan is to replace ObamaCare.

Trump responded by repeatedly saying the centerpiece of his plan would be to allow insurers to cross state lines.

“Now he's the one repeating himself,” the Florida senator said, cracking a big smile as the crowd erupted in cheers and laughter.

In the GOP debate days before the New Hampshire primary, New Jersey Gov. Chris Christie, has has since dropped out of the race, accused Rubio of repeating scripted lines on stage, in a moment that hurt Rubio.

On Thursday, it was Rubio who turned the tables on an opponent. 

Trump responded, calling Rubio’s previous debate performance a “meltdown”: “I watched him repeat himself five times four weeks ago.”

“I saw you repeat yourself five times five minutes ago,” responded the senator.

The crowd again hollered its approval for a beaming Rubio, who piled on from there: “He says five things: Everyone is dumb, he's going to make America great again, win, win, win, he's rising at the polls, lines around the state.”

Rubio dredged up scores of past scandals that have touched Trump in his decades in business, some of which will likely be new to viewers tuning in to Thursday’s debate.

Rubio bashed Trump for having a line of clothes manufactured in Mexico and China. He brought that argument home after Trump said he’d make Mexico pay for a wall along the southern border by declaring a trade war.

“You’re declaring a trade war on your own ties and suits,” Rubio said. “Why don’t you make them in America?”

He savaged the real estate mogul for “bankrupting four companies,” running a “fake university” that he’s now being sued over, and for being born into a wealthy family.

“If he hadn’t inherited $200 million you know where he’d be right now?,” Rubio asked. “Selling watches in Manhattan.”

Cruz also got into the action, alleging that Trump had paid a $1 million fine for hiring illegal immigrants and accusing him of “funding” the Gang of Eight immigration bill by donating to the senators who crafted the legislation.

The Texan blasted Trump for donating to Democrats “who advocate for far left judicial activists,” and accused Trump of supporting “socialized medicine.”

It was far from clear that the attacks by Rubio and Cruz would hurt Trump, who was quick on his feet an on several occasions, delivering his own stinging comebacks.

Responding to Rubio’s accusation that he had hired illegal immigrants, Trump said: “I've hired tens of thousands of people, you've hired nobody."

And after Cruz bashed Trump for donating to some of the lawmakers who crafted the Senate immigration bill, Trump shot back by noting that Cruz has not been endorsed by even one of his colleagues in the upper chamber.

“You should be ashamed of yourself,” Trump said.

In one exchange, Trump stood stoically as Cruz rebuked him for “funding liberal politicians for 40 years.”

“I funded you,” Trump said dryly.

That provoked a shouting match and one of the few points in the night when Trump went for the kill, calling Cruz a “basket-case.”

“You’re losing so bad and you don’t even know what’s happening,” Trump said, shaking his head.

The celebrity businessman also seemed to have an eye on the general election, delivering a strong case about his electability by citing the droves of first-time voters and independents who have delivered him three consecutive victories in the race for the GOP nomination.

“We are building a new Republican Party,” Trump said. “A lot of new people are coming in. I will do really well with Hispanics. I’m tell you also, I’m bringing Democrats over and independents over and we’re building a much bigger and a much stronger Republican Party.”

John Kasich and Ben Carson were also in the debate but were invisible for much of the night as Trump, Rubio and Cruz went at it.

“Can somebody attack me, please,” Carson pleaded at one point.