Joe Biden was the big winner as New York billionaire Mike Bloomberg suspended his presidential campaign and endorsed the former vice-president while Massachusetts Senator Elizabeth Warren was reassessing her candidacy.

Mr Bloomberg quit the race that will determine Donald Trump’s opponent in November just over 100 days after he got in despite pouring more than 500 million US dollars of his personal fortune into his campaign.

The massive investment only netted him a win in American Samoa.

Mr Bloomberg joined Amy Klobuchar, Pete Buttigieg and Beto O’Rourke as former Democratic presidential contenders to endorse Joe Biden.

The development came just hours after a resurgent Mr Biden scored Super Tuesday victories from Texas to Massachusetts, revitalising a presidential bid that was teetering on the edge of disaster just days earlier.

Mr Biden and Mr Bloomberg spoke Wednesday morning, according to two people familiar with the situation.

Mr Biden’s rival Bernie Sanders seized the biggest prize with a win in California that ensured he, and his embrace of democratic socialism, would drive the Democrats’ nomination fight for the foreseeable future.

Ms Warren, Mr Sanders’ progressive ally, was huddling with advisers on Wednesday to determine if there was a reason to stay in the race after her Super Tuesday wipe-out.

She did not win a single state and finished in third place, after Mr Biden and Mr Sanders, in her own home state of Massachusetts.

Suddenly, the Democratic Party’s presidential field, which featured more than a half-dozen candidates a week ago, transformed into effectively a two-man contest.

Mr Biden and Mr Sanders, lifelong politicians with starkly different visions for America’s future and who are older than the current president, were locked in a delegate fight a day after 14 states and one US territory held a series of high-stakes elections that marked the most significant day of voting in the party’s presidential primary.

It could take weeks, or months, for Democrats to pick one of them to take on President Donald Trump in the November general election.

But the new contours of the fight between Mr Biden and Mr Sanders crystallised as the former vice president and the three-term Vermont senator spoke to each other from duelling victory speeches delivered from opposite ends of the country Tuesday night.

US Election
Joe Biden was Barack Obama’s vice-president (Nick Potts/PA)

“People are talking about a revolution. We started a movement,” Mr Biden said in Los Angeles, knocking one of Mr Sanders’ signature lines.

Without citing his surging rival by name, Mr Sanders swiped at Mr Biden from Burlington, Vermont.

“You cannot beat Trump with the same-old, same-old kind of politics,” Mr Sanders declared, ticking down a list of past policy differences with Biden on Social Security, trade and military force.

“This will become a contrast in ideas.”

The Sanders campaign announced Wednesday that it would begin airing three new campaign ads in Arizona, Florida, Idaho, Illinois, Michigan, Mississippi, Missouri, Ohio and Washington, states that hold primaries March 10 and March 17.

One of the new ads features archived footage of former President Barack Obama praising Mr Sanders.

It was a not-so-subtle attempt by the Vermont senator to undercut Mr Biden’s frequently spotlighting his closeness to Mr Obama.

Mr Trump went on Twitter on Wednesday to call Mr Biden’s strong Super Tuesday showing “a perfect storm” and amplify his long-running argument that the Democratic Party would move to stop Mr Sanders from winning the nomination.

“The Democrat establishment came together and crushed Bernie Sanders, again!” Mr Trump tweeted.

Mr Trump also called Warren “selfish” for staying in the race because it “hurts Bernie badly”.

Mr Biden’s victories were powered by Democratic voters who broke his way just days before casting their ballots, a wave of late momentum that scrambled the race in a matter of hours.

In some states, the late-deciders made up roughly half of all voters, according to AP VoteCast, surveys of voters in several state primaries.

He drew support from a broad coalition of moderates and conservatives, African Americans and voters older than 45.

Mr Sanders’ success proved he could deliver in perhaps the greatest test of his decades-long political career.

His success was built on a base of energised liberals, young people and Latinos.

But he was unable to sufficiently widen his appeal to older voters and college graduates who make up a sizeable share of Democratic voters, according to AP VoteCast.

The balance of Super Tuesday’s battlefield, with Mr Biden winning at least nine states and Mr Sanders four, raised questions about whether the Democratic primary contest would stretch all the way to the July convention or be decided much sooner.

Mr Biden’s strong finish punctuated a dramatic turnaround in the span of just three days when he leveraged a blowout victory in South Carolina to score sweeping victories on Tuesday that transcended geography, class and race.

And lest there be any doubt, he cemented his status as the standard-bearer for the Democrats’ establishment wing.