COLUMBIA, S.C. — Most Joe Biden admirers Axios interviewed in South Carolina, where he's vowed to win today's primary, said they're unfazed by his embarrassing losses in Iowa, New Hampshire and Nevada.

Why it matters: Biden has bet it all on South Carolina to position himself as the best alternative to Bernie Sanders — his "good buddy," he tells voters before skewering Sanders' record and ideas.

The state of play: If Biden wins South Carolina commandingly, he lives to fight on Super Tuesday, three days from now. But if Sanders manages to even come close, it'll fuel his juggernaut.

Polls show Biden leading here by 20 points, but his supporters feel the weight of his national political survival on their shoulders — and Sanders is whittling away at Biden's lead.

The Democratic primary is still a crowded field, and that has hurt moderates and boosted Sanders. Billionaire candidate Tom Steyer has spent and campaigned enough in the state to also impact results.

By the numbers: Real Clear Politics polling averages have Sanders in the lead in California, Virginia, Texas and North Carolina — all crucial Super Tuesday states.

FiveThirtyEight estimates that if Sanders were to win in South Carolina, he could end up with a little more than half of all the pledged delegates after Super Tuesday — and be in strong shape to win the nomination.

What we're seeing: Most people at the rallies we attended here were staunch supporters the day before the primary. Unlike in Iowa and New Hampshire, where voters are still shopping around, here in South Carolina you meet people who’ve voted early and still show up to their candidates' events.

Joe's hand: Many voters we talked to described feeling a personal connection with Biden because of his longtime ties to the state.

Biden has vacationed there for years, and his friendship with Rep. Jim Clyburn gives him credibility with older African-American voters.

In South Carolina, where a majority of Democratic voters are African-American, you can't talk to a Biden supporter without Barack Obama's name also coming up. "He trusted Biden," said Sue Gibbs, 68.

But some worry about Biden's gaffes and memory lapses, and what Trump would do to him in a general election.

"He doesn't seem as sharp as I would like, and that concerns me," said Mary Beth Berry, an undecided voter who loves Pete Buttigieg but doesn't think he has enough national support to win.

Bernie's' hand: Sanders is establishing himself as the one to beat for the nomination. And the fact that he's in second place in South Carolina — after being crushed there in 2016 — shows how fast Democratic Party politics are changing.