Voters in South Carolina are going to the polls today to have their say on the Democratic presidential nominee, and it is a must-win primary for the former US Vice President Joe Biden.
Once the frontrunner in the race, Mr Biden has struggled in the first three contests of the primary season. He came fourth in Iowa, fifth in New Hampshire and finished in a distant second-place in Nevada.
He is hoping that South Carolina will be different.
The state has a large African-American population and Biden has traditionally polled well among black voters.
He received a boost in recent days when the influential African-American Congressman James Clyburn endorsed him.
"I'm voting for Joe Biden, and South Carolinians should be voting for Joe Biden," he said.
"I know Joe. We know Joe. But most importantly, Joe knows us."
During the most recent Democratic debate on Tuesday, Biden said he was confident he will win South Carolina.
"I've worked like the devil to earn the vote of the African-American community, not just here, but across the country. I've been coming here for years and years, creating jobs here," he said.
According to the polls, Biden is still the favourite to win South Carolina but today's vote is a make-or-break moment for the Biden campaign.
Losing the state would deliver a major blow to his candidacy, winning would send out a strong signal that he is still in the race.
Joe Biden says victory would be a springboard for future primaries, but a better description might be a lifeline for a struggling campaign.
The early primaries are all about momentum and right now that momentum is with Vermont Senator Bernie Sanders.
He won the popular vote in Iowa and secured a narrow victory in New Hampshire, but his best result came in Nevada.
A big win there showed that he could appeal to a diverse range of voters, something he has struggled with in past campaigns.
But if the early states are about momentum, 'Super Tuesday' is all about delegates.
At least 1,991 pledged delegates are needed to win the Democratic nomination on the first ballot at the party’s convention in July.
Just days from now, on 'Super Tuesday', Democrats will vote in 14 US states and in the US territory of American Samoa. Democrats abroad will also begin voting.
There are a massive 1,357 delegates up for grabs on Super Tuesday - that's more than a third of the total delegate count.
Big states will be voting like California, where 415 pledged delegates are up for grabs, and Texas with its 228 delegates.
To put those numbers in context, only around 100 delegates have so far been allocated and just 54 are available today in South Carolina, so even if Joe Biden is declared the winner later tonight, he's facing a long road ahead with lots of challenges.
One of the biggest threats will come from billionaire Michael Bloomberg, who has skipped the early voting primaries and has instead been pumping millions of dollars into advertising and campaigning in bigger states.
For Joe Biden, before he can even think about Super Tuesday, he needs today to be his 'Salvation Saturday'.
