US Election debate: ‘Donald, you can get back on your meds now’

US senators Marco Rubio of Florida and Ted Cruz of Texas aimed a ferocious pincer attack at Republican front-runner Donald Trump in the final debate before next week’s bumper ‘Super Tuesday’ of 11 state contests.

The two trailing candidates hit the billionaire repeatedly with criticisms during an explosive 10th debate, held in Texas, as they try to make up ground on a runaway Mr Trump after his three straight victories in the first four qualifying rounds in the race to the Republican presidential nomination.

Mr Cruz, who won Iowa in the first nominating state but who has come third in each of the three state contests since then, jabbed Mr Trump for his past support of Democrats.

He also questioned his conservatism and said he was not the best candidate to face Hillary Clinton in the November election.

Mr Rubio, showing a new aggressive streak against Mr Trump as he needs a victory in at least one state after four unconvincing finishes, rounded on Mr Trump for his employment of illegal Polish workers, his sketchy healthcare plans and his loose grasp on Middle Eastern policy.

The exchanges at times descended into moments of chaos with candidates shouting over each other and slinging personal insults, behaviour more suited to a schoolyard than to an American presidential debate stage as CNN news anchor Wolf Blitzer, one of four moderators, struggled to maintain order.

Mr Trump shot back at the tag-team assault against him from the two first-term senators, calling Mr Rubio “a choke artist”and Mr Cruz “a liar,” and repeatedly pointing out that he was leading both candidates in the polls.

One of the debate’s more bizarre incidents came when the Texas senator, debating on home ground in Houston, noted that Mr Trump had funded “liberals Democratic politicians for 40 years.” The tycoon fired back that he had given Mr Cruz money and Mr Rubio had sent him an autographed book.

“Yeah, you gave me $5,000,” replied Mr Cruz. “I gave him a cheque,” said Mr Trump, before the two proceeded to talk over each other.

“He never funded me,” said Mr Rubio, interjecting.

“You know why? I didn’t want you,” said Mr Trump.

“Donald, you can get back on your meds now,” said Mr Cruz, trying to calm the businessman down to continue making a point.

“This is a lot of fun up here tonight, I have to tell you,” said Mr Trump, continuing. “Thank you for the book. I really appreciate it,” he said to Mr Rubio.

“Donald - Donald, relax,” said Mr Cruz, again trying to interrupt to speak.

“Go ahead. I’m relaxed - you’re the basket case,” replied Mr Trump. “Go ahead. Don’t get nervous.”

“I promise you, Donald, there’s nothing about you that makes anyone nervous,” Mr Cruz responded.

For the first time in a debate, Mr Rubio took on Mr Trump after months of resisting going where other candidates have fallen, notably former Florida governor Jeb Bush who dropped out of the race last weekend.

The Floridian’s new-found belligerence comes as he must find a way to out-manoeuvre Mr Trump as the four trailing candidates head into next Tuesday’s 11 state contests needing to halt his march towards the nomination.

A new Bloomberg poll showed the billionaire is supported by 37 per cent of likely Republican presidential primary voters in seven southern states voting next Tuesday, ahead of Mr Rubio and Mr Cruz who are tied on 20 per cent.

Debating the topic of immigration, the 44-year-old Rubio accused Mr Trump of being “the only person on this stage that has ever been fined for hiring people to work on your projects illegally” and of lying about it.

The property developer dismissed Mr Rubio’s incident as “such a cute sound bite” and an incident that happened 38 years ago.

“Oh, he lied 38 years ago. All right, I guess there’s a statute of limitations on lies,” said Mr Rubio, to laughter from the audience.

Stamping his own conservative credentials on the topic, Mr Cruz said that in 2013 he was fighting the Senate’s “amnesty” immigration bill, co-authored by Mr Rubio.

"Where was Donald? He was firing Dennis Rodman on Celebrity Apprentice," he said, referring to Mr Trump's reality TV career.

Ironically, one of the highlights for Mr Rubio was his own reference to one of the lowlights of his debate performances in the campaign: his exchange from the New Hampshire debate with one-time candidate Chris Christie when he was accused of repeating canned lines from his stump speech.

Questioning Mr Trump’s healthcare policy, Mr Rubio pushed the billionaire to provide more details.

“Now he’s repeating himself,” he said when Mr Trump made reference to a stock phrase about his plan a number of times.

“I don’t repeat myself. I don’t repeat myself,” said Mr Trump, attempting to make himself heard over cheers and applause from the crowd.

On the Israeli-Palestinian situation, Mr Trump described himself as a negotiator in contrast to Mr Rubio.

“I watched him melt down and I’ll tell you: it was one of the saddest things I’ve seen,” the businessman said, referring to his spat with Mr Christie.

Mr Rubio counterpunched, telling that Mr Trump that “the Palestinians are not a real estate deal.”

The senator also questioned the businessman’s willingness to fight trade wars with China and Mexico when he bought clothes made in those countries.

“So you’re gonna be starting a trade war against your own ties and your own suits,” said the senator.

Opening up a potentially vulnerable front for the New York businessman, Mr Trump was questioned by Mr Blitzer about former Republican nominee Mitt Romney calling on him to release his back tax returns and saying there was “good reason to believe there is a bombshell in them.”

Mr Trump tried to block the avenue of attack, saying that he was routinely audited and that he would release his tax returns once they were audited.

Mr Blitzer asked Mr Trump about a comment by former Mexico president Vicente Fox that he was “not going to pay for that f**king wall,” referring to the businessman’s election promise to make Mexico pay for a wall at the border to stop migrants entering the country illegally.

“I will,” said the billionaire repeating the promise, “and the wall just got 10 feet taller, believe me.

“I saw him use the word that he used,” Mr Trump added, about Mr Fox’s choice of language.

“I can only tell you, if I would have used even half of that word, it would have been a national scandal.”