Biden once described speaking to a group of students back when he was a rookie senator, many years ago, and telling them he had no plans to seek the White House.

He got called out by a sister.

«I could see a nun at the back of the room stand up. ‘You know that’s not true, Joey Biden,’ she said as she pulled from the folds of her habit a paper I’d authored in grade school,» Biden wrote in Promises To Keep, the memoir he released for his second presidential run, not to be confused with Promise Me, Dad, released for this, his third presidential run.

«I’d written that I wanted to be president when I grew up, she said. So I was caught red-handed.»

Nearly half a century later, following two unsuccessful presidential runs spanning four decades, his aspirations so notorious his denials became their own punchline, he’s finally won one presidential contest.

And boy did he need this one.

Biden hurtled into Super Tuesday with momentum and a message: for voters hoping to stop Sen. Bernie Sanders, he’s now the best bet.

Barack Obama’s former vice-president rode a wave of nostalgia for the former administration and won decisively in the first state where the majority of voters were black.

Biden won by nearly 30 percentage points, and came close to wiping out the lead in convention delegates Sanders had amassed in earlier states.

Biden himself alluded to South Carolina’s history of backing winners: It’s chosen the eventual Democratic nominee in four of five competitive cycles since 1992.

«You launched Bill Clinton, and Barack Obama, to the presidency,» Biden told a victory rally Saturday night.

«For all those of you who’ve been knocked down, counted out, left behind, this is your campaign.

«Just days ago the press and the pundits had declared this candidacy dead.… We are very much alive.»

Another candidate, billionaire Tom Steyer, quit the race Saturday.

Other candidacies will be made and broken this Tuesday.

More than one-third of the delegates in this nomination cycle are up for grabs in a single day — with 14 states voting.

The good news, bad news for Biden

The good news for Biden is that a few Super Tuesday states are similar to South Carolina — in geography, demography, and voting history.

Five of the 14 states are also in the South; also have large black populations; have more centrist voters; and they all rejected Sanders in 2016.

«A strong turnout in South Carolina will send signals to all the other southern states,» said Todd Shaw, associate director of African-American studies at the University of South Carolina.

One South Carolina Democrat emphasized the ripple-effect potential with a personal anecdote.

Jaime Harrison, running for the U.S. Senate this fall against incumbent Lindsey Graham, called it a «springboard» effect across the South. People in nearby states look at South Carolina, he said.

«As my grandma said, ‘We’ve got relatives all across the South. And they look at what we do in South Carolina.'» Harrison said in a podcast chat.

«And that has a factor in what happens on Super Tuesday. We saw it with President Obama [in 2008], we saw it with Hillary Clinton [in 2016], and you’ll probably see it again with the winner of our primary.»

That’s the good news for the former VP. Now a word of caution for those in the throes of Bidenmania.

It’s still an uphill battle.

It’s important to note Biden will face an important new rival on Super Tuesday: billionaire Mike Bloomberg is set to enter the race, competing for the anti-Sanders vote with limitless resources at his disposal, as evidenced by the generous selection of free barbecue he’s doling out to people who attend his rallies.

Bloomberg isn’t the only competitor with deeper pockets than Biden.

Biden started February with $7 million US left of $69 million raised. Sanders had almost $10 million more in the bank, on $134 million raised. Even Pete Buttigieg raised more than the former vice-president. And that was before Biden’s catastrophic showings in the first two states, followed by a more respectable second place in Nevada.

Then there’s his California problem.

The most populous state in America holds 415 delegates — by far the biggest prize on Super Tuesday, with more than 10 per cent of this year’s overall total.

He’s polling dismally there. If he, and other candidates, fail to win the minimum 15 per cent of the vote, Sanders could conceivably walk off with most or even all of those massive electoral spoils. It’s no accident Sanders headed straight for California this weekend.

So Biden and his team will begin making a more emphatic case to the large cross-section of Democrats who oppose Sanders.

The message: It’s Biden or bust.

Sanders has already begun efforts to unite the Democratic Party around him with general-election-style campaign messaging.

In South Carolina, Sanders focused almost exclusively on attacking President Donald Trump in a tease of what he’d sound like as a candidate this fall.

Sanders mentioned, barely in passing, that he’d be likelier to beat Trump than Biden, because of his lifelong progressive record and ability to fire up young voters and get them to turn out.

Biden’s crowds this week in South Carolina weren’t as large as Sanders’s.

But he spent lots of time with people at his smaller events, taking questions and lingering afterward to sign autographs.

Biden did so in a school gymnasium where a smallish crowd of a few dozen people lined up to meet the former vice-president in Sumter, S.C.

He took subtle digs at Sanders. As he did in his victory speech Saturday, Biden suggested that what Americans voters want after Trump is competent, stable government — not systemic overhaul.

«This nation isn’t looking for a revolution. We’re looking for progress. For results,» he said in Sumter.

When asked what would be his first three priorities as president, Biden promised to re-enter the Paris climate accord on Day One of his presidency; send Congress an immigration plan; and tackle education reform.

But one wavering voter appeared to suggest he might try emulating Sanders a bit. She asked Biden what motivates him.

«You see Bernie and you see Elizabeth Warren and you see that fire,» Marybeth Berry asked at the Sumter event.

«What is your fire?»

Biden’s reply: «Decency and honour.»

In a lengthy response, the ex-VP said that just because he doesn’t scream like Sanders and wave his arms like Warren doesn’t mean he lacks passion.

Biden went on to mention fighting inequality and injustice, abuse of power, men who hurt women, and he spoke of lessons learned from his father.

After the event, Berry said she was still wavering between Sanders and Biden, though inching closer to the Biden camp.

But what if Sanders wins?

The vast majority, but not all, Democrats tell exit pollsters they’d vote for whoever becomes the party nominee. Given the closeness of most U.S. presidential races, the party can’t afford to fragment this fall.

Berry said she’d vote for anyone against Trump — literally anyone. She pointed to a CBC reporter and said: «I’d vote for you.»

But, she was reminded, it’s illegal for non-Americans to run for president.

Berry shrugged, «Whatever.

«At this point,» she said, «what we have in the White House is a disgrace.»