A somber Republican presidential candidate field took the debate stage in Greenville, South Carolina Saturday night, hours after learning of Supreme Court Justice Antonin Scalia's death.

The winnowed field of six - Donald Trump, John Kasich, Ted Cruz, Marco Rubio, Ben Carson, and Jeb Bush - stood in a moment of silence beforehand. CBS News moderator John Dickerson's first question to Donald Trump was whether President Obama should nominate Scalia's successor during the remainder of his term.

"If the president, if I were president now, I would certainly want to try and nominate a justice and I'm absolutely sure that President Obama will try and do it," Trump said. "I hope that our Senate is going to be able - Mitch (McConnell) and the entire group - to do something about it in times of delay."

Trump added, "This is a tremendous blow to conservatism. It's a tremendous blow, frankly, to our country."

The other candidates recommended Obama delay filling Scalia's vacancy. Rubio, for one, believed Scalia "defended consistently the original meaning of the Constitution," adding that rulings today are often made by fads of the moment.

"Someone on this stage will get to choose the balance of the Supreme Court and it will begin by filling this vacancy now that's there now," Rubio said. "We need to put people on the bench that understand that the Constitution is not a living and breathing document. It is to be interpreted as originally meant."

Trump and Bush spar over foreign policy, 9/11

Asked about Russia's involvement in fighting ISIS, Bush said Russia is attacking the U.S. and its affiliates in Syria. He brought up the fact that Trump wants to accommodate Russia's involvement in the Middle East, reigniting debate of whether President Vladimir Putin can be considered an ally.

Trump's unfinished response - "Jeb is so wrong, Jeb is absolutely so..." - drew a chorus of boos.

"You know who that is? That's Jeb's special interest and lobbyist talking," Trump replied, reminiscent of a similar moment during last weekend's New Hampshire debate.

Dickerson asked Trump if former President George W. Bush should have been impeached for the Iraq war, specifically comments that it would have been "a wonderful thing."

Trump said the war was "a big, fat mistake," a conclusion he accused Jeb Bush of flip-flopping on. Asked again if the former president should be impeached, Trump emphasized that "They lie, they said there were weapons of mass destruction and there were none, and they knew there were none."

Bush defended his brother's record and said he could care less about Trump's insults towards him. "While Donald Trump was building a reality TV show, my brother was building a security apparatus to keep us safe, and I'm proud of what he did," Bush said.

In response, Trump insinuated that 9/11 was George W. Bush's fault.

"The World Trade Center came down under your brother's reign."

Rubio defends tax and immigration plans, says Cruz can't speak Spanish

One weekend after New Jersey Gov. Chris Christie called him out for canned responses, Rubio seemed to win over the South Carolina crowd by defending his proposed 35-percent tax plan; a plan that would increase parents' refund under the Child Tax Credit.

"If you're a parent that's struggling you know that $50 a month is the difference between a new pair of shoes this month or not getting a new pair of shoes for your kids," Rubio said. "I'm going to have a tax plan that is pro-family because the family is the most important institution in society. You cannot have a strong country without strong families."

When the subject turned to immigration, Rubio defined amnesty as "the forgiveness of the wrongdoing without forgiveness," something he claimed to never support. He favors consequences for violating immigration laws.

Rubio said the only way to prove that immigration laws work is by following through on promises to hire more border agents, build a wall along the U.S.-Mexico border, and implement an entry-exit tracking system.

"I think the American people will be very reasonable, but responsible, about how you handle someone who's been here a long time. Who can pass a background check, who pays a fine and starts paying taxes, and all they want is a work permit," Rubio said. "But you can't do any of that until you prove to people that illegal immigration is under control once and for all."

Cruz, who promised to overturn President Obama's executive action on immigration, was asked whether he would deport undocumented immigrants he knows of. The Texas senator reverted back to his record of opposing amnesty, and reminded viewers that Rubio supported the Gang of Eight bill.

Rubio, as he's done following Cruz's attacks in previous debates, restated his argument that Cruz has flip-flopped on immigration too.

"We're going to have to do this again," Rubio said, before recalling that Cruz proposed doubling the number of green cards and guest workers. "Now he is a passionate opponent of all those things. So he either wasn't telling the truth then or he isn't telling the truth now. But to argue he is a purist on immigration is just not true."

When Cruz reference an interview Rubio had with Univision, Rubio asked "I don't know how he knows what I said on Univision because he doesn't speak Spanish."

South Carolina polls

A pair of surveys released Friday each had Trump with double-digit leads over Cruz.

The August Chronicle had Trump up 36-20, followed by Rubio at 15 percent and Bush at 11 percent. In an SC House GOP survey, 34.5 percent of respondents chose Trump, compared to 15.5 for Cruz; Rubio earned 12.5 percent.

Kasich placed fourth and Carson came in dead last in both polls.