7 Moments That Mattered at the South Carolina GOP Debate

With the Republican presidential field whittled down to just six candidates, the first presidential debate since the New Hampshire primary and the last one before the Palmetto State's Feb. 20 nominating contest turned into a rollicking attack-fest that left virtually no contender unscathed.

During one of the debate's feistiest exchanges -- a shout-out between Donald Trump and Ted Cruz -- the moderator, John Dickerson of CBS News, invited the Texas senator to "pick from the buffet" of jabs that had just been leveled.

And the debate, held at the Peace Center in Greenville, South Carolina, was exactly that: A smorgasbord of sharp volleys that were as often about policy as they were personal.

Here are seven moments that mattered:

1. Supreme Court Vacancy: What Would You Do?

The unexpected death of U.S. Supreme Court Justice Antonin Scalia on Saturday generated the first question of the debate with the candidates weighing in on what they would do if they were in President Obama's position.

Trump said if he were president he would "certainly want to try and nominate a justice," but added he hoped the GOP-controlled Senate would be able to block Obama's pick.

Ohio Gov. John Kasich argued that Obama should let the next president decide on a replacement: "I really wish the president would think about not nominating somebody."

Sen. Marco Rubio agreed: "It's been over 80 years since a lame duck president has appointed a Supreme Court justice."

Cruz, called on the U.S. Senate to "stand strong" when President Obama nominates a replacement for Scalia as he said he intends to do.

"We're not gonna give up the U.S. Supreme Court for a generation by allowing Barack Obama to make one more liberal appointee," Cruz said.

2. Jeb vs. Trump Round One: Bush Gets His Exclamation Point

Trump and Jeb Bush have long been rivals in this campaign and in debates they often spar, but tonight Bush earned his exclamation point, taking on the real estate mogul. The two went back and forth for several rounds, but it all began when the former Florida governor jabbed Trump, accusing him of being accommodating to Russia in the fight against ISIS.

"Jeb is so wrong," Trump said.

As the audience began to boo him and as he did last week at the ABC News debate, Trump took on the crowd, saying, "Just so you understand? That's Jeb's special interests and lobbyists talking."

"I only tell the truth, lobbyists," he added. The two went back and forth sparring on the right way to beat ISIS, with Trump saying, "You've got to fight ISIS first. You fight ISIS first."

Bush interrupted, firing back at Trump: "This comes from a guy who gets his foreign policies from the shows."

Trump responded by noting his big win in New Hampshire this week, as well as mentioning Bush backer former presidential candidate South Carolina Sen. Lindsey Graham.

"Lindsey Graham, who backs him, who had had zero in his polls," Trump said, digging in.

3. Jeb vs. Trump Round Two: Family Feud

The fight between the two rivals got even nastier minutes later when Bush declared himself "sick and tired" of Trump's attacks on his family.

"While Donald Trump was building a reality TV show, my brother was building a security apparatus to keep us safe," Bush said.

Trump fired back: "The World Trade Center came down during your brother's reign. Remember that?" His remark elicited boos from the crowd inside the debate hall.

During the same exchange, Bush assailed the billionaire businessman for having "gall to go after my mother." Trump has mocked Bush for having his 90-year-old mother, former First Lady Barbara Bush, campaign for him.

"She should be running," Trump deadpanned.

4. Jeb vs. Trump Round Three: Let's Talk About Weakness

But it didn't end there. When the conversation turned to immigration reform, Trump attempted to deliver yet another body blow to Bush.

"The weakest person on this stage by far on illegal immigration is Jeb Bush," he said.

The former Florida governor was having none of it.

"You want to talk about weakness?" Bush asked. "It's weak to disparage women. It's weak to disparage Hispanics. It's weak to denigrate the disabled. And it's really weak to call John McCain a loser because he was a P.O.W."

5. Things Get Caliente Between Rubio and Cruz

An argument over immigration records between the two senators on stage became so heated that it turned into a fight over who speaks Spanish.

Cruz criticized Rubio's immigration reform bill he helped write with Democratic Sen. Chuck Schumer as part of the "Gang of Eight" and argued the Florida senator was for amnesty.

"In addition to that, Marco went on Univision in Spanish and said he would not rescind President Obama's illegal exclusive amnesty on his first day in office," the Texas senator said.

"First of all, I don't know how he knows what I said on Univision because he doesn't speak Spanish," Rubio shot back.

Cruz responded in Spanish, challenging Rubio: "My friend, if you want to tell them now, tell them now in Spanish."

Rubio continued his attack on Cruz.

"Ted Cruz has just been telling lies," Rubio said. "He lied about Ben Carson in Iowa. He lies about Planned Parenthood, he lies about marriage. He is lying about all sorts of things and now he makes things up."

6. The 'Biggest Liar'

After Rubio called Cruz a liar, Trump upped the ante, calling the Texas senator the "single biggest liar."

It happened when Cruz accused Trump of supporting policies that "have been very, very liberal."

"You are the single biggest liar," Trump said. "You probably are worse than Jeb Bush."

Cruz went on to say Trump would appoint liberals to the Supreme Court, and this: "Donald, adults learn not to interrupt each other."

7. Trump Says He Will Cut Back on the Profanity

Trump is known for telling it like it is on the campaign trail, but also for letting loose in the profanity department. Tonight, he said he would stop.

When asked if he would be willing to cut out the bad language, Trump answered that on "occasion, in order to sort of really highlight something, I'll use a profanity."

But he promised to cut back.

"I have said I will not do it at all, because if I say a word that's a little bit off color, a little bit, it ends up being a headline," Trump said. "I will not do it again. I was a very good student at a great school. By the way, not using profanity is very easy."