He added: “You cannot beat Trump with the same old same old kind of politics.”

Yet millions of people on Tuesday night disagreed with the Vermont senator. While polls in California continue to be counted, we know at least 4,477,262 voted for the “same old kind of politics” on Super Tuesday when they cast their ballots for Joe Biden, handing him at least 433 delegates.

By contrast, Sanders, who had gone into the race as the de facto frontrunner after wins in Iowa, New Hampshire and Nevada, received the 3,647,154 votes, bringing his delegate hall to 380.

It may be, by the time the counting is done, the 78-year-old Sanders emerges with a similar delegate haul to the 77-year-old Biden. What is certain is that momentum lies with the younger man.

On Wednesday morning, Michael Bloomberg, the former New York mayor who spent $500m of his own money to insert himself into the democratic process, said he was dropping out and endorsed the former vice president.

“I’ve always believed that defeating Donald Trump starts with uniting behind the candidate with the best shot to do it,” he said. “After yesterday’s vote, it is clear that candidate is my friend and a great American, Joe Biden.”

By contrast, while there is pressure on progressive Elizabeth Warren to end her campaign, it is unclear if she would endorse Sanders, Biden or neither.

The battle for the nomination is far from over. There are many more states to vote. Is there anything Sanders could do to stop the surge of the centrist “establishment” politician many of his supporters have little time for?

“The issue has always been about electability and that is because of Donald Trump,” said Jeanne Zaino, Professor of Political Science at Iona College in New York.“There was a realisation among many Democrats that for all his flaws Joe Biden was probably the best chance. But certainly Bernie Sanders was not a viable option for beating Trump.”

She added “The more Trump tweeted about Bernie being robbed it became clear he does not want to run against Biden.”

Ms Zaino said Mr Sanders could try to expand his appeal by diluting some of the policies many believe to be too progressive – Medicare For All and free college education – but that he was unlikely to do so.

“Those things he won’t do and because of that it’s going to hurt him in terms of getting the nomination, and even if he gets it he won’t win in those swing states that decide to hold their nose and vote for Trump,” she said. “It’s just not possible.”

Data collated by Politico suggests Biden won the support of large swatches of the electorate, as he claiming victory in ten states, compared to four for Sanders.

A week ago in South Carolina, Biden managed to secure 61 per cent of the American American vote. On Super Tuesday he repeated similar figures in North Carolina (62 per cent, Alabama (70 per cent) and even Virginia.

It said while Sanders won college-educated white Democrats in Vermont and two states with significant early voting, California and Colorado, Biden swept at least nine other states among that group of voters.

Super Tuesday: Jo Biden talks about campaign turn-around

Meanwhile, Biden won non-college-educated white voters in eight Super Tuesday states, compared with four for Sanders. Politico said many of Sanders strongest performances were in places where early voting took place.

As a result, they may have failed to reflect the major shake-up that followed Biden’s landslide win in South Carolina last weekend, which in turn led Pete Buttigieg and Amy Klobuchar to drop out and back Biden.

On his plus side, Sanders continued to secure the support of younger voters and Latinos, two groups that helped him win his own blow out in Nevada last month. Yet, those people did not turn out in enough numbers to win Texas, a huge, diverse state and the second most sought-after win in terms of delegates, other than Texas.

“Sanders has consistently promised he’d expand the Democratic electorate by motivating millions of young people and new voters to show up at the polls. It hasn’t happened,” said Larry Sabato, professor of politics at the University of Virginia.

“And if it hasn’t happened now, it’s unlikely to occur in a general election after he has a billion dollars of negative ads dropped on him by the Trump campaign.”

Asked whether Sanders was capable of diluting his stance on issues such as universal health care, he said: “Sanders can’t afford to compromise on Medicare for All. I doubt he’s going to pull back from much of anything.”

On Wednesday, Sanders not appear to be backing down.

In comments to supporters in Vermont, but directed at Biden, he said a presidential campaign funded by the rich could not produce president who put working people first

“Are you on the side of working people, and are you willing to stand up against the greed and corruption of the corporate elite,” he said.

“Or are you on the side of the billionaires and corporations that are trying to buy the election?”