Story highlights

Ted Cruz and Donald Trump fought over Cruz's eligibility to be President and his citation of "New York Values"

Marco Rubio had a late rally with a hit on Cruz over immigration and his Senate voting record

Rand Paul, invited to the early debate, skipped the proceedings altogether in favor of a media blitz

CNN —  

Donald Trump and Texas Sen. Ted Cruz dropped their buddy-buddy act – trading blows in explosive exchanges over Cruz’s Canadian birth and his denunciation of Trump’s “New York values.”

The two stole the show the Fox Business Network debate in North Charleston, South Carolina, where Republicans met for their second-to-last debate before the Iowa caucuses.

“I guess the bromance is over,” Trump told CNN’s Dana Bash afterward.

Here are six takeaways from Thursday night’s debate:

Birtherism: Cruz wins the battle, Trump wins the war

Cruz was ready to attack Trump over the real estate mogul’s assertion that Cruz’s Canadian birth (to a U.S. citizen mother) makes him vulnerable to accusations he is ineligible for the presidency, pointing out that Trump said in September that Cruz is, indeed, on solid legal footing.

“Since September, the Constitution hasn’t changed. But the poll numbers have,” Cruz said.

He said following Trump’s logic to the furthest possible extent, Trump’s own qualifications could be questioned due to the businessman’s Scottish-born mother.

As Cruz rebutted Trump for raising the issue – effectively winning the moment – Trump essentially held his hands up and said he’s not the one who’s concerned.

“I’m beating you,” Trump said. “I think I’m going to win fair and square.”

And he succeeded in keeping the question alive – a loss, in and of itself, for Cruz. Trump asked: “If you become the nominee, who the hell knows if you can even serve in office?”

That’s the point Harvard law professor Laurence Tribe, the legal source Trump has cited and Cruz has dismissed as liberal, made on CNN after the debate. “If he did put it to bed, he’s certainly sleeping alone,” he said.

Opinion: Who won Trump-Cruz smackdown?

New York, New York

Trump seemed genuinely taken aback by Cruz’s insult of his “New York values.”

Cruz explained that jab, saying: “Everyone understands that the values in New York City are socially liberal, are pro-abortion, are pro-gay marriage, focused around money and the media.”

That led Trump to launch into a lengthy, emotional defense, pointing to New York City’s response to the September 11, 2001, terror attacks.

He said that “the people of New York fought and fought and fought, and we saw more death – the smell of death was with us for months.”

“We rebuilt Downtown Manhattan, and everybody in the world watched and loved New York and loved New Yorkers,” he said.

Trump’s response was moving, but to Cruz it was also predictable. That Cruz stuck with his “New York values” criticism anyway highlights his strategy as the campaign enters its final days: Cruz is heavily courting the evangelicals who dominate the GOP contests in Iowa and South Carolina.

Trump-Cruz ‘bromance’ is over

The real four-man main stage

Trump and Cruz were at the center of the night’s most memorable exchanges, but Florida Sen. Marco Rubio and New Jersey Gov. Chris Christie traded blows as well.