Polling of tomorrow’s South Carolina GOP primary gives Donald Trump a clear lead, so it looks very likely that he will win the Palmetto State. The key question is margin: does he win big, or does he underperform (or even overperform)?

The more interesting race on the Republican side is for second place. The last couple of polls show Marco Rubio overtaking Ted Cruz for second place. This is probably going to be close, but with the recent endorsement of Rubio by Gov. Nikki Haley, I think he does slip past Cruz to take second. Rubio likely will be assisted by the continuing fade of Jeb Bush and the fact that John Kasich appears unable to build on his second-place finish in New Hampshire.

If the South Carolina Republican primary plays out as expected, then it will put Rubio back in front of the establishment pack and probably mark the moment when the Bush and Kasich campaigns begin seriously reassessing the point of staying in the race. Both are polling in the low-double digits to high-single digits, and their prospects continued viability will not look hopeful if, as expected, they end up in a battle for fourth place, far behind the top three finishers. Whoever finishes the lowest between these two may hang around long enough to roll the dice at next Tuesday’s Republican caucuses in Nevada, but the loser (especially if it’s Kasich, who doesn’t have Bush’s financial wherewithal) is probably out shortly thereafter. Whoever performs better in this two-man race likely hangs in, just in case Rubio falters again, but the fifth-place finisher is all but certainly going to be out of the race in a matter of days.

Ben Carson, of course, has no chance to be the nominee; at this point and going forward, he can only hurt other candidates. If he places ahead of Bush and/or Kasich tomorrow, it might well do enough damage to whomever he defeats as to end either or both campaigns right away. More importantly, he now remains the only impediment to Cruz in the evangelical lane. Carson has raised a shocking amount of money, so he may stay in regardless of his performance tomorrow, but if he does, it benefits Trump and Rubio.

My predictions, based on the recent polls and trends:

  1. Trump
  2. Rubio
  3. Cruz
  4. Bush
  5. Kasich
  6. Carson

In the Nevada Democratic caucuses, there has been very little reliable polling, and polling tends to be off for the Nevada caucuses at any rate. I expect Hillary Clinton to win a narrow victory over Bernie Sanders, but honestly, this is an educated guess. There just isn’t much data there. If Sanders has gained significant ground among Latinos, he could certainly prevail. There’s just no reliable way to tell yet.