Here are 5 things to watch in the South Carolina primary on Saturday

Key Points
  • The Democratic presidential primary will head to its first Southern state on Saturday for the South Carolina primary, the fourth nominating contest of the 2020 cycle.
  • While Sen. Bernie Sanders has racked up a delegate advantage in the first three states, the race remains very much in flux.
  • Former Vice President Joe Biden is leading in polls of South Carolina, and he is favored to win his first primary.
Supporters cheer as Democratic presidential hopeful former Vice President Joe Biden arrives to speak at a rally in Conway, South Carolina, on February 27, 2020.
Jim Watson | AFP | Getty Images

The Democratic presidential primary will head to its first Southern state on Saturday for the South Carolina primary, the fourth nominating contest of the 2020 cycle.

While Sen. Bernie Sanders, I-Vt., has racked up a delegate advantage in the first three states, effectively tying former South Bend, Indiana, Mayor Pete Buttigieg in Iowa and then carrying New Hampshire and Nevada, the race remains very much in flux.

In part, that's because of just how few delegates have been awarded so far. Only about 100 of the nearly 4,000 pledged delegates have been won so far, and Sanders' lead over Buttigieg remains less than 20.

In addition, a historically crowded field has complicated the path to obtaining a majority of the delegates in the states to come.

Polls will open early Saturday morning and close at 7 p.m. ET, after which results are expected to start coming in.

Here are five things to watch.

Can Biden collect enough momentum?

Former Vice President Joe Biden has called South Carolina his "firewall" and said during the Democratic debate in Charleston this week that he expected to win first place.

That finish is quite possible: According to public polling average, Biden is ahead of his nearest challenger, Sanders, by double digits, and the lead is growing.

But even if Biden snags his first first-place finish, his campaign faces steep odds for capitalizing on the victory in time to make a comeback by Super Tuesday, just three days after the South Carolina primary.

Biden was the last contender to devote substantial advertising money to the Super Tuesday states, announcing a six-figure spend on Wednesday. On Thursday, the campaign upped the spend to just over $2 million, which is still less than Sanders and even Sen. Amy Klobuchar, D-Minn. A pro-Biden super PAC has also stepped up its investment in Super Tuesday markets.

The 14 states that vote on Super Tuesday will collectively award about a third of the primary's total delegates. For Biden, turning a South Carolina victory rapidly into momentum in those states will be a heavy lift — and essential.

A test for Sanders' popular appeal

Sanders faces the toughest state for his candidacy yet after winning the most votes in the first three early states of the primary.

During his 2016 battle against former Secretary of State Hillary Clinton, Sanders took only a quarter of the vote in South Carolina, getting beat by nearly 50 points.

During the 2020 cycle, Sanders has improved his standing among black voters and is looking to perform better in the state. He is polling at about 22% in state polls, or about 12 points behind Biden.

That gap has widened in recent days after a somewhat rocky debate performance from Sanders on Tuesday, the first debate in which he was targeted as the clear front-runner by his rivals. On Wednesday, Biden received the endorsement of South Carolina's most powerful Democrat, Rep. James Clyburn, the House majority whip.

The question for Sanders appears to be whether he can finish in a strong enough second place to preserve his momentum heading into Super Tuesday, where he has devoted more resources than any candidate who is not a billionaire.

Black voters finally weigh in on Buttigieg

Buttigieg has faced questions since the start of his presidential bid about his record on race and policing.

But his flagging support among black and other minority voters did not hurt him in the largely white states of Iowa and New Hampshire. He received just 2% of the black vote in Nevada, where black voters made up about 10% of the electorate, which dinged his bid.

In South Carolina the black vote is a different story.

Black voters made up more than 60% of the state's Democratic electorate in 2016. Last cycle, Clinton beat Sanders by about 70 points among black voters in the state, according to CNN exit polling data, contributing to the belief that the self-described democratic socialist lacked appeal to a key Democratic constituency.

Buttigieg has long said that he underperforms among black voters because he is new on the scene and will do better once they get a chance to know him. He is running out of time to make his introductions.

Will Steyer's millions matter?

There are two billionaires running for the Democratic nomination, but only one of them will be on ballots in South Carolina.

Tom Steyer, the former hedge-fund manager, has spent $14 million on television and radio ads. Steyer also spent heavily in the previous states that voted, including more than $10 million in Nevada.

Former New York Mayor Mike Bloomberg, in contrast, is spending hundreds of millions of dollars on his bid but is targeting the states that vote on Super Tuesday. Bloomberg did not run in the first four states of the primary race.

While it remains to be seen what kind of return on investment is waiting for Bloomberg, for Steyer the evidence is somewhat bleak.

The businessman and philanthropist has not secured a single delegate in the states that have voted so far. He may not do better in South Carolina.

Candidates will need to receive at least 15% support at the congressional district or state level in order to be viable in South Carolina. At the moment, after sliding in recent days, Steyer's average in state polling is just under that threshold, according to RealClearPolitics.

Dropout calls will intensify

The Democratic primary field has remained surprisingly large headed into Super Tuesday.

After Saturday, it's likely that candidates who have not performed well in the first four states to vote will be called on to drop out. Of course, they might not do so.

The pressure is particularly acute on the race's moderates, such as Biden, Klobuchar, Buttigieg and Bloomberg.

That's because it is looking increasingly likely that Sanders could emerge from Super Tuesday on track to build an insurmountable lead in delegates, effectively securing the nomination.

The moderate contenders may be limiting each other from receiving delegates, a problem compounded by the 15% threshold to receiving delegates. This conundrum is particularly evident in a state like California, the biggest delegate prize of the entire primary, which votes on Tuesday.

There, Sanders is averaging just over 31% in state polls, followed by Sen. Elizabeth Warren, who is hovering above the 15% viability level. Biden, Bloomberg and Buttigieg are each just below that threshold, somewhere between 10% and 15%.

That leaves the potential that Sanders could run away with more than 400 pledged delegates just from California, despite not winning even a majority of the state vote.

While the calls for some candidates to drop out will likely escalate, none of the contenders still in the race have signaled that they intend to go away any time soon.

"I am going to stay right to the bitter end," Bloomberg told NBC News in a Thursday interview, "as long as I have a chance."