An emboldened Joe Biden is trying to cast himself as the clear moderate alternative to progressive Bernie Sanders as the Democrats’ shrinking presidential field races toward Super Tuesday.

One of Mr Biden’s leading moderate rivals, former South Bend, Indiana, Mayor Pete Buttigieg, dropped out of the campaign on Sunday just 24 hours after Mr Biden scored a resounding victory in South Carolina, his first of the 2020 roller coaster nomination fight.

While other rivals appeared undeterred, Mr Biden pressed his case during a round of national television interviews that reflected a stark reality a day after his resounding primary victory in South Carolina.

The former vice president was forced to rely upon free media coverage because he was understaffed, underfunded and almost out of time as he fought to transform his sole win into a national movement.

US Election
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Mr Biden vowed to improve his campaign operation, his fundraising haul and even his own performance in an interview on ABC’s This Week.

He warned of a “stark choice” between him and Mr Sanders, while making the case he was the candidate who could win up and down the ballot and in states beyond those voting next week.

Mr Biden added a swipe at one of Mr Sanders’ signature lines during an appearance on Fox New Sunday: “The people aren’t looking for revolution. They’re looking for results.”

The newfound confidence came at a crossroads in the Democratic Party’s turbulent primary season.

Mr Sanders remained the undisputed front-runner.

Election 2020 – Bloomberg
Michael Bloomberg will be on the ballot on Super Tuesday (Daily Memphian/PA)

But the rest of the field was decidedly unsettled, even after Mr Biden’s South Carolina success and Mr Buttigieg’s sudden departure.

Most notably, New York billionaire Mike Bloomberg could create problems for Mr Biden as the race speeds toward Super Tuesday, when 14 states from Maine to Alabama to California hold Democratic elections as the 2020 primary moves into a new phase.

No longer will individual states hold primaries every week.

Starting Tuesday, and most Tuesdays through early June, batches of states will vote at the same time in what has essentially become a national election.

US presidential election 2020; Super Tuesday
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Mr Biden claimed a handful of new endorsements and fundraising successes on Sunday in his quest to project strength.

Perhaps the most powerful endorsement would come from former President Barack Obama, who has a relationship with most of the candidates and has talked with several in recent weeks as primary voting has begun.

He spoke with Mr Biden after his South Carolina victory, but still has no plans to endorse in the primary at this point.

But a handful of high-profile political strategists with ties to the former president encouraged Mr Biden’s rivals, including Mr Bloomberg, to quit the race to allow anti-Sanders’ Democrats to unify behind Mr Obama’s former vice president.

“Most of them have seen the writing on the wall for at least the last week,” said Rufus Gifford, who held top fundraising posts on both of Obama’s campaigns and was part of Biden’s fundraising operation.

“It’s clear the Democratic alternative to Bernie Sanders is Joe Biden.”