Before Sen. Bernie Sanders (I-VT) lost South Carolina to former Vice President Joe Biden, the socialist candidate was told to attack the long-presumed inevitable candidate and newcomer Mike Bloomberg.

Sanders didn’t listen.

Just before the South Carolina primary – which Biden swept – the remaining Democrat candidates participated in a televised debate. Politico reported that advisers to Sanders told him to go after Biden’s record and Bloomberg’s support of stop-and-frisk policies:

Two of Sanders’ top advisers — pollster Ben Tulchin and speechwriter David Sirota — told Sanders that he should pointedly take on Biden at the Feb. 25 debate in South Carolina, which the former vice president saw as his firewall state. They also said Sanders should use billionaire Mike Bloomberg as a foil, and attack him over his record of supporting stop-and-frisk, in order to deflect from the onslaught he would no doubt face as the newly anointed frontrunner. The stakes were high: In an email to senior staff, Tulchin said that moderate voters were beginning to unify behind Biden and that the consolidation would intensify if he won South Carolina, according to people familiar with the message. But on the stage that night, Sanders didn’t take his aides’ advice. Instead, he largely gave Biden a pass, bashed Bloomberg sometimes — but not over stop-and-frisk — and mostly stuck to his standard talking points. It wasn’t the first nor the last time Sanders eschewed his staffers’ suggestions to be more aggressive with his top rival. Their warnings proved prescient: Biden went on to sweep the day in South Carolina, unify moderates, and then carry Super Tuesday.

One top aide told the outlet that “Knocking out Biden was job No. 1.”

“And even when he was down, no one went for a knockout blow,” the aide continued. “That was the problem.”

This, according to Politico, is just one of the ways that led to Sanders’ campaign failure. The outlet said Sanders performed worse with some demographics in 2020 than in 2016, even though he was more well-known and had a loyal following. “He badly lost among African-Americans yet again, and the rural and working-class white voters who were with him four years ago abandoned him,” the outlet reported.

Sanders campaign manager Faiz Shakir also blamed the media for its role in squashing the Vermont senator’s chances.

“Sadly, we did not get to a place of convincing a large number of people that he was the most quote-unquote the electable choice,” Faiz Shakir, Sanders’ campaign manager, told POLITICO this week. “It turned into a superficial media perception of ‘safe, electable Biden’ versus ‘revolutionary Bernie Sanders.’ And I think that dynamic kind of hurt.”

Other aides told Politico that Sanders should have acted presidential after his win in Nevada, but instead he spent that time defending his positive comments about Cuban dictator Fidel Castro. Some aides said Sanders never conducted focus groups to determine how to attract black or elderly voters.

Former Sanders surrogate Ja’Mal Green also said the candidate needed to hire more diverse staffers.

“The problem was in 2016 and 2020 he had some of the same top aides that made the campaign make some wrong decisions,” Green told the outlet. “There wasn’t enough money put into talking to black older voters who didn’t have an opinion on Bernie or didn’t like Bernie.”

In a major sign of defeat, Sanders tried and failed to get high-profile progressives to endorse him, such as Sen. Elizabeth Warren (D-mA), Andrew Yang and Tom Steyer, though Yang said Sanders only asked to speak to him, not endorse him.

The most embarrassing part of Sanders’ loss is probably this line from Politico: