5 Moments That Mattered in the Republican Debate

NORTH CHARLESTON, South Carolina -- The first Republican presidential debate of 2016 was also one of the feistiest. Seven candidates -- the fewest of any of the previous debates -- took the stage in North Charleston, South Carolina and took the gloves off.

The debate was indicative of a Republican primary that is fast reaching its boiling point just less than three weeks before the Iowa caucuses, and the most intense sparring took place between the two candidates locked in a neck-and-neck race in that state: Donald Trump and Ted Cruz.

Here are five moments that mattered at tonight's GOP debate:

1. Trump and Cruz Dive Into 'Natural Born Citizen' Argument

In recent weeks Donald Trump has brought up the "natural born citizen" argument about Ted Cruz, questioning whether he is constitutionally able to run for president since he was born in Canada to an American mother. This evening, the moderators asked about the issue and Cruz said it wasn't an issue for Trump in September.

"Back in September, my friend Donald said he had his lawyers look at this from every which way and there was no issue there," Cruz said, noting Trump "is dismayed that his poll numbers are falling in Iowa."

2. Cruz Confronts Goldman Sachs Loan

When moderators asked Ted Cruz about a recent New York Times piece on Cruz not disclosing a loan on a federal form, Cruz hit back.

After bashing the media and Hillary Clinton, he admitted: "I made a paperwork error." Cruz told voters that he did file the loan on a state form. "But if that is the best hit New York Times has got, they better go back to the well."

3. Cruz Throws Trump's "New York Values" Back At Him

When asked about his hit earlier this week on Trump's "New York values," Cruz clarified that they are "socially liberal or pro-abortion or pro-gay marriage."

He then turned around a Trump attack on him, saying, "Not a lot of conservatives come out of Manhattan," an apparent reference to Trump telling crowds that "not too many evangelicals come out of Cuba."

Trump turned serious in his response, though, citing New York's response to the 9/11 attacks and telling his rival: "That was a very insulting statement that Ted made."

4. Rubio Throws Kitchen Sink at Cruz

Tonight's debate was without a Ted Cruz-Marco Rubio showdown for most of the evening, but after 11 p.m. the two finally went head to head with the Florida Senator throwing the kitchen sink at the Texas Senator.

Rubio accused Cruz of flip flopping on immigration, birthright citizenship, crop insurance, trade legislation, ethanol subsidies, and even said Cruz wanted to cut military spending.

Rubio jabbed: "That is not consistent conservatism. That is political calculation."

Cruz hit back saying the allegations are "absolutely false" adding he appreciates "your dumping your research folder on the debate stage."

5. Rubio Spars With Christie Over Record

Chris Christie and Marco Rubio went head-to-head over Christie's record in New Jersey.

"I like Chris Christie but we can not afford to have a president of the United States that supports common core," Rubio said, also hitting Christie on gun control.

But sparks flew as Christie hit back. "I like Marco too. And, two years ago he called me a conservative reformer that New Jersey needed," Christie said. "That was before he was running against me. Now that he is he's changed his tune."