Tom Goldstein: “The best candidate politically would probably be Hispanic.  Hispanic voters both (a) are more politically independent than black voters and therefore more in play in the election, and (b) historically vote in low numbers.  In that sense, the ideal nominee from the administration’s perspective in these circumstances is already on the Supreme Court:  Sonia Sotomayor, the Court’s first Latina.”

“On the other hand, I think the President personally will be very tempted to appoint a black Justice to the Court, rather than a second Hispanic.  His historical legacy rests materially on advancing black participation and success in American politics.  The role Thurgood Marshall previously played in that effort is inescapable.  The President likely sees value in providing a counterpoint to the Court’s only black Justice, the very conservative Clarence Thomas.”

“For those reasons, I think the President will pick a black nominee.”

Politico: “The free-for-all unmasked the dynamics that have largely played out by press release or in one-off one-liners on the campaign trail. It’s a sign of the rising stakes in South Carolina, which could define the contours of the race over the next few months as a three-way contest among Trump, Cruz and an establishment-backed candidate like Rubio, Bush or Kasich. Ben Carson, a retired neurosurgeon who has trailed in polls, is also hoping the squabbling helps lift his soft-spoken brand, though he had few opportunities to stand out during the debate.”

“It’s unclear which blows hit their mark and who will emerge at the top of the battered heap of rivals. But each candidate urgently needed a strong showing.”

If Donald Trump wins the GOP nomination, the Republican party as we know it is over.

In tonight’s debate, Trump blamed George W. Bush for 9/11 happening on his watch and confirmed that he would have impeached him for invading Iraq. Polls show that both George W. Bush and the Iraq war are still very popular with Republicans. But if everything we’ve seen over the last nine months holds, it seems likely that Trump will get 30% of the vote in South Carolina no matter what he says.

Jeb Bush was high energy tonight and took every swing he could at Trump. He was fighting like it was his last chance. He even took shots at John Kasich. If this version of Bush had been running for the last year, it might be a very different race today. It was his strongest debate by far.

Ted Cruz stayed away from a much-anticipated battle with Trump until the last half hour when it turned into one of the nastiest exchanges of the debates so far. Cruz attacked Trump hard, but Trump won. Cruz also went after Marco Rubio hard on immigration but didn’t win that exchange either. Perhaps Cruz was thrown off his game at the very beginning when John Dickerson corrected him on facts about Supreme Court nominations.

Rubio was better tonight than the last debate — a low bar, of course — but he still talks on 1.5X speed. It makes him sound like… yes, a robot. He landed some good punches and generally avoided damage by staying out of a fight with Trump.

Kasich is getting better at these debates but unless he has a stronger finish in South Carolina, it’s hard to see where he goes. He seems like a nice guy but he’s simply out of step with his party on too many issues.

Ben Carson needs to end his campaign now. He adds nothing to these debates with his repeated call outs for his website.

The bottom line: I’m not sure any candidate won this debate. It was like, as First Read foreshadowed last month, the final scene in Reservoir Dogs “where everyone has their weapons pointed at each other and, well, a lot of people are going to die.”

One final thought: The audience was an abomination. Letting them hoot and holler after every answer made the debate feel like it was taking place in a Roman coliseum. It was a total embarrassment for the Republican party.

The Republican presidential candidates meet for their ninth debate at 9 p.m. ET in South Carolina.

• Will Donald Trump finally come under fire from his rivals?
• Can Marco Rubio rebound after a disastrous performance in the last debate?
• Will news of Justice Antonin Scalia’s death change the course of the GOP race?

The debate will be broadcast and streamed live on CBS News.