Something was wrong with the voting technology, but it was clear Bernie Sanders had once again had a good night in Iowa.

It was not as good as four years earlier, when he’d chased and harried Hillary Clinton to within less than a single point. Nevertheless, it was enough for him to claim victory, of the popular vote, if not the delegate haul.

“I’ve a good feeling the results would be released at some point,” he said. ”I have a good feeling when they are, we’ll be doing well in Iowa.”

It would be the same in New Hampshire and then Nevada. With so many candidates occupying the moderate ground and thus diluting the anti-Sanders vote, the 78-year-old was rapidly emerging as the Democrats' presumptive challenger to Donald Trump.

Democratic candidates compete on the campaign trail: In pictures Show all 18 1 /18 Democratic candidates compete on the campaign trail: In pictures Democratic candidates compete on the campaign trail: In pictures Jessica Canicosa, a precinct captain for Bernie Sanders, waits to greet caucus voters at Liberty High School in Henderson, Nevada REUTERS Democratic candidates compete on the campaign trail: In pictures Hotel workers at the Bellagio in Las Vegas get to grips with voting papers during the Nevada caucuses AFP via Getty Images Democratic candidates compete on the campaign trail: In pictures A caricature of Bernie Sanders is projected on to a tree during a rally in Las Vegas EPA Democratic candidates compete on the campaign trail: In pictures A woman waits to have a photo taken with Elizabeth Warren during a town hall meeting in Las Vegas REUTERS Democratic candidates compete on the campaign trail: In pictures The threat of coronavirus and other germ-borne illnesses was on some voters' minds at the Democratic caucuses in Henderson, Nevada Getty Images Democratic candidates compete on the campaign trail: In pictures Former vice-president Joe Biden takes a selfie with a voter in Las Vegas ahead of the Nevada caucuses REUTERS Democratic candidates compete on the campaign trail: In pictures Amy Klobuchar changes her shoes backstage after giving a speech in Exeter, New Hampshire AFP/Getty Democratic candidates compete on the campaign trail: In pictures A warmly-wrapped-up dog attends an Elizabeth Warren event at Amherst Elementary School in Nashua, New Hampshire AFP/Getty Democratic candidates compete on the campaign trail: In pictures Bernie Sanders, who romped to victory in New Hampshire against Hillary Clinton in 2016, talks to the media in Manchester Getty Democratic candidates compete on the campaign trail: In pictures Joe Biden was hoping to improve on his poor showing in Iowa in the New Hampshire primary Reuters Democratic candidates compete on the campaign trail: In pictures Elizabeth Warren, renowned for giving time to supporters for selfies, works the crowd at the University of New Hampshire in Durham Getty Democratic candidates compete on the campaign trail: In pictures Joe Biden takes a selfie with a supporter and his child outside a campaign event in Somersworth, New Hampshire on 5 February Reuters Democratic candidates compete on the campaign trail: In pictures Elizabeth Warren and Bernie Sanders quarrel after a confrontation in a TV debate in which Sanders claimed that Warren was not telling the truth about a conversation in which she claimed he had said a woman could not win the presidency on 14 January AP Democratic candidates compete on the campaign trail: In pictures Supporter Pat Provencher listens to Pete Buttigieg in Laconia, New Hampshire on 4 February Getty Democratic candidates compete on the campaign trail: In pictures Pete Buttigieg speaks at a campaign event in Concord, New Hampshire while awaiting the results of the Iowa caucus Reuters Democratic candidates compete on the campaign trail: In pictures Elizabeth Warren is presented with a balloon effigy of herself at a campaign event in Nashua, New Hampshire on 5 February Reuters Democratic candidates compete on the campaign trail: In pictures A Trump supporter rides past a rally for Amy Klobuchar in Des Moines, Iowa on 14 January AP Democratic candidates compete on the campaign trail: In pictures A man holds up a sign criticising billionaires in the presidential race in front of Michael Bloomberg in Compton, Califronia. The former New York mayor skipped the first caucus in Iowa and instead campaigned in California on 3 February Reuters

Then everything appeared to go wrong. Firstly Joe Biden, 77, secured a landslide in South Carolina, persuading several other candidates to drop out and endorse him. That was followed by another solid performable by Biden on Super Tuesday, and on two successive rounds of primaries.

After he was trounced in Florida and Illinois, campaigning by then having been largely suspended because of the Covid-19 emergency, many assumed Sanders would drop out of the race.

Now he has. On Wednesday morning, a day after the Wisconsin primary, also overshadowed by the coronavirus crisis, the Vermont senator could not with “good conscience” stay in the race.

“Please note that I do not make this decision lightly. In fact, it’s a very difficult and painful decision,” he said, his face for once looking tired and deflated.

Plenty were quick to praise Sanders, among them young progressives, such as Alexandria Ocasio-Cortez. Others said he should have vacated the stage some time earlier, better to allow Biden to focus on challenging Trump.

Sanders, who was first elected to office in 1981 when he become mayor of Burlington, Vermont, certainly deserves credit for making mainstream policies that were once limited to the fringes. On issues such as access to healthcare, climate change and reform of the criminal justice, Sanders’s success in energising and engaging with young voters, obliged other candidates to reframe their own platforms, Biden among them.

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“Sanders exits the race having changed what’s possible in American politics. He defended the idea of a country built around a government that ensured meaningful equity better than anyone has,” says Matthew Schmidt, associate professor of political science at the University of New Haven. “He made millions understand that government could effectively create a nation with radically fairer access to healthcare, wealth, and political representation.”

As it is, Sanders is not giving up entirely. He said on Wednesday his name will remain in the ballot in the remaining races and he will hold onto his delegates in order to better put pressure on the policy platform process this summer.

“As you all know, we have never been in just a campaign. We are a grassroots multiracial multi generational movement,” he said.

In that decision was contained much that delighted and inspired his supporters and confounded his critics. To those who packed out stadiums to be part of his “revolution”, the man from Brooklyn was an unbending, incorruptible beacon. Others saw him as arrogant and inflexible and unwilling to do what was needed to appeal to a broader audience.

Observers say one of Sanders’s biggest mistakes was his failure to reach out sufficiently to African American voters, especially older voters. Decisions such as the skipping of the annual civil rights memorial walk at Selma, Alabama, now appear misguided, even as he built support among Latino voters.

As it was, it was Biden who secured key black endorsements, such as congressman Jim Clyburn of South Carolina, among the most powerful elected black officials in the nation.

“I think that he definitely focused on Latinx populations, as his path to victory,” says Christina Greer, professor of political science at New York’s Fordham University. “But there is no path to a Democratic victory without African American voters. If you don’t understand that or appreciate, that and try and cultivate that, then you have zero chance.”

Larry Sabato, professor of politics at the University of Virginia, suggests this was Sanders’s gravest error

“Sanders should have spent far more time between 2016 and 2020 cultivating African-American support,” he says. “The lack of black votes knocked him out cold in South Carolina, enabling Biden to sweep almost any state with a large black vote in Democratic primaries.”

An irony is that while Joe Biden is now the Democrats’ presidential nominee in all but official pronouncement, he will need Sanders and his support more than ever. While Biden will secure money and official help now he is the last man standing, he will not necessarily win the votes of Sanders’ supporters.

Four years ago, estimates suggest as many as 12 per cent of those who voted for Sanders in the Democratic primary, voted for Trump rather than Clinton in the general election. Given Trump only secured the White House by just 70,000 votes across three states, it is unclear what impact those die-hard supporters of Sanders played.

Some Sanders grass roots supporters see Biden in similar terms to the way they viewed Clinton – an establishment politician who would do little for them. Biden will hope that confronted by the prospect of another four years of Trump, most of Sanders’s base will not back the incumbent.

But he cannot take that for granted, something he appeared to recognise in the tribute his paid on Wednesday to Sanders.

“To your supporters I make the same commitment: I see you, I hear you, and I understand the urgency of what it is we have to get done in this country,” he said. “I hope you will join us. You are more than welcome. You’re needed.