The 5 most likely outcomes in the South Carolina primary

After Saturday, the campaign goes WAY national, with 14 states and American Samoa voting on Super Tuesday.

So what's going to happen? Here are my five most likely scenarios -- ranked.

5. Buttigieg overperforms: In Iowa and New Hampshire, the former South Bend, Indiana, mayor overperformed polls and expectations. (He won Iowa and placed a surprisingly strong second in New Hampshire.)

Could that happen again in South Carolina? Polling puts Pete Buttigieg in fourth, but there's absolutely a scenario where he passes wealthy businessman Tom Steyer as voters make final decisions.

Is a third place finish for Buttigieg good enough? Especially with Super Tuesday -- where he has no obvious wins waiting -- right over the horizon?

4. Sanders wins: If this happens, the race is essentially over. Not just for Joe Biden, who has to win in South Carolina. For everyone.

That's not to say that everyone not named "Bernie Sanders" will immediately drop out. They won't. But Sanders would springboard from a huge South Carolina upset into Super Tuesday just three days later -- and would likely build an insurmountable delegate lead.

He would have also shown an ability to win white voters (Iowa, New Hampshire), Hispanic voters (Nevada) and black voters (South Carolina). That would be curtains for everyone else.

3. Steyer underperforms: The "other" billionaire businessman in the Democratic race is currently running a solid third behind Biden and Sanders in South Carolina polling.

But Steyer's poor showing in the first three votes makes him an uncertain bet for South Carolina voters. Human nature suggests that people like to vote for someone they think can win -- and Steyer doesn't look like a winner (or even close) right now.

Do voters swayed by Steyer's long-running TV ad campaign in the state stay in his camp? Or do they go hunting for a candidate that looks more like a winner?

2. Biden wins by single-digits: Polling in the final days of the race here have been all over the place. They all show a Biden lead but disagree whether it is a big or small one.

While Biden would take any sort of victory in South Carolina -- he is done unless he wins -- there's no question that a single-digit victory is less than ideal.

If Sanders comes anywhere close to beating Biden in South Carolina, it would almost certainly soften any bounce for the former vice president heading into Super Tuesday.

1. Biden wins by double-digits: The former vice president has not only been ahead for months and months in the state but also has gone all out to win big here -- from spending New Hampshire primary night in South Carolina to his work to win the endorsement of Rep. Jim Clyburn.

A double-digit win for Biden would likely mean an absolutely dominant performance among the state's black community, which will comprise roughly 60% of the electorate tomorrow.

And that would bode well for Biden's chances on Tuesday, with a number of southern states -- Alabama., Virginia, North Carolina -- with major black populations set to vote.

Biden badly needs a jolt of momentum and a clear win in South Carolina would give it to him.