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.

“Knocking out Biden was job No. 1. And even when he was down, no one went for a knockout blow,” said a top aide. “That was the problem.”

Sanders’ unwillingness to go for Biden’s jugular is just one of the decisions campaign aides are wrestling with since he exited the primary Wednesday. Despite being the best fundraiser in the Democratic field, having near universal name ID, and leading a massive volunteer army, Sanders performed worse in many ways in 2020 than in 2016. 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.

According to interviews with more than 20 of Sanders’ aides, surrogates and top allies, many believe he should have been more aggressive in taking on Biden, including over the idea that he was more electable in November. They also complained about the campaign’s organizing strategy and its inability to win over black and senior voters. Though nearly everyone in Sanders’ circle felt that the media and political establishments played critical roles in taking him down, they still think the nomination was in his reach.

“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.”

***

It’s difficult to remember now, but Sanders was once seen as unstoppable.

After winning Nevada, where he won 50 percent of Latino voters and finished only 10 points behind Biden among black voters, moderate Democrats panicked that Sanders would roll into Super Tuesday with unrelenting momentum. And since he had shown significant strength among voters of color, they worried he might even take South Carolina.

Instead, Sanders lost there by 29 percentage points. In an epic display of political strength and coordination, moderates then rushed to consolidate behind Biden, a feat capped by his rivals Pete Buttigieg and Amy Klobuchar dropping out and endorsing him.

Some Sanders aides think he should have used the period between Nevada and South Carolina to appear presidential and broaden his appeal, including to seniors. That was the idea behind a sit-down interview he did with Anderson Cooper on “60 Minutes.” Instead, he spent much of his time doubling down on defending positive comments he made in the 1980s about Cuban dictator Fidel Castro’s education program.

Aides said that weakened his case on the single-most important issue to Democratic voters: beating President Donald Trump. Some suggested he strongly condemn the Cuban regime and get off the subject quickly. He didn’t take their advice and instead drew out the exchange at the South Carolina debate, arguing that “Cuba, Nicaragua, authoritarianism of any stripe is bad,” but that former President Barack Obama had also praised Cuba’s educational program.

“Should we have spent basking in the sun of our Nevada win by talking about Fidel Castro? Not what I would have done,” said one aide. “Should we have used that time to really open up and become a much bigger tent or were we focused on continuing to shore up the progressive vote?”

Some staffers believe Sanders also should have done more to break through on electability, an issue that was even more important to older and African-American voters among whom he was weakest. He never conducted focus groups on the issue — or any issue — because of a dislike of such campaign tactics, aides said.

A few top advisers felt that Sanders would be seen as more electable once he won early states and that the matter would take care of itself, while others argued that the campaign should have more directly made the case.

One option they said worked well at the doorsteps was arguing that when Democrats nominated “safe,” establishment choices, such as Hillary Clinton and John Kerry, they lost — and that Biden was the latest in a long line of mainstream nominees whose appearance as a sure winner was a mirage. But instead, the candidate typically used his go-to lines on the subject — that he defeated Trump in nearly every poll, and winning in November would require unprecedented turnout and excitement — which failed to stick.

Jane Sanders, the senator’s wife and closest adviser, acknowledged that there was more they could have done to persuade people that he was as electable as Biden: "The facts were on our side. We didn't do it well enough. That is something we should have done better."

Bernie Sanders had expected to spend more time in South Carolina — where African-Americans cast more than half the vote in Democratic primaries — in the weeks before the primary there. But the senator had to scale those plans back due to the impeachment proceedings, said people familiar with his schedule. Some of Sanders’ advisers and allies felt that especially hurt him because he tended to do better with voters who saw him up-close.

“We’ve got to do better at building relationships with the African-American community,” said Ro Khanna, Sanders’ campaign co-chair, of the progressive movement. “I don’t think we have done enough.”

Ja’Mal Green, a former Sanders surrogate, said that while the senator brought on a more diverse group of aides than in 2016, and his 2020 team included African-American advisers such as campaign co-chair Nina Turner and national press secretary Briahna Joy Gray, Sanders needed additional senior black staffers.

“The problem was in 2016 and 2020 he had some of the same top aides that made the campaign make some wrong decisions,” he said. “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.”

Around the same time that Biden was consolidating moderates behind him, Sanders attempted to bring the progressive wing of the party fully behind him. He talked to Warren over the phone multiple times after she dropped out after Super Tuesday, a top aide said. He asked for her endorsement, as well as for a nod from Andrew Yang and Tom Steyer, the staffer said. (Yang said Sanders “called the night I suspended, congratulated me and invited me to meet with him,” but did not directly request an endorsement.) None threw their weight behind him.

“He was deeply disappointed that she didn’t endorse afterward,” said a person familiar with his talks with Warren. “It made him question her progressivism. Now maybe that was temporary, but I think he was very hurt by that because he would have endorsed her in a heartbeat if it was the other way around.”

Some Sanders staffers said the campaign’s polling made a bad situation worse. A Tulchin survey showed a close race in South Carolina in the weeks before the primary. At one point, Sanders grew so frustrated with Tulchin’s polling that he considered moving polling in-house, said an aide.

***

In total, Sanders’ team reported knocking on more doors and calling more voters than any other candidate in the race — and yet he still lost to Biden, who didn’t even campaign in some states where he coasted to victory.

That lopsidedness has led to soul-searching among progressives about the value of field organizing. But some Sanders aides argue that the impressive voter contact numbers the campaign released concealed deep disagreements over organizing.

Some senior staffers were skeptical about the organizing team’s experiments. Iowa aides said they mostly stopped using the “Bern” app, an organizing tool made in-house, for some time because it wasn’t fully developed and lacked precinct matching information. Staff also complained that some canvassing scripts in the days before primaries were focused on persuasion for undecided voters, instead of solely getting out the vote.

At a meeting with top aides a few months before the Iowa caucuses, senior adviser Chuck Rocha raised concerns about the fact that they lacked precinct captains for hundreds of caucus sites in the state. Some staffers felt that was partly due to the fact that they required captains to go through in-depth training. On the day of the Iowa caucuses, while the vast majority of caucus sites were covered, the campaign had no precinct captains in some rural areas, said several aides.

“We had a lot of last-minute work in shipping out-of-state volunteers to act as precinct captains in rural areas,” said an Iowa Sanders staffer.

Buttigieg’s ultimate victory in rural parts of the state helped him run up the delegate score and win Iowa. Claire Sandberg, Sanders' national organizing director, felt that campaign leadership should have hired more field staff earlier in 2019 across states, including Iowa, according to a person familiar with her thinking. Others said that Sanders should have visited more rural areas there. A planned campaign swing in rural Iowa was scrapped because of impeachment.

Conflict between senior aides and the organizing operation culminated in February when Sandberg was layered by Misty Rebik, the former Iowa state director who was named the team’s national director of organizing and field.

Even critics of the organizing program concede that the best-run field operation can only move a few points in a close race. But Sanders lost to Biden by double-digits in at least a dozen states.

Many in the campaign partly blame cable TV for that, with the media-tracking service Critical Mention estimating that Biden enjoyed nearly $72 million in almost completely positive earned media in the days between South Carolina and Super Tuesday. But some of Sanders’ aides and allies also think they could have done a better job handling the press.

They think the campaign should have had more surrogates on MSNBC and other cable news channels. Staffers were also told at times not to pitch opposition research on rivals — a standard job for the communications shop on most campaigns — due to the fact that Sanders disliked negative campaigning. And Sanders sometimes rebuffed the press: According to an MSNBC spokesperson, the network had a longstanding invitation for Sanders to participate in a town hall, but he declined.

Some of Sanders’ allies felt he should have brought on longtime professionals who knew and could better deal with the mainstream media.

“He needed to hire somebody who could talk to the corporate media and could call in favors,” said a surrogate.

Sanders’ team zeroed in on the liberal network MSNBC early on in the campaign as a particular problem. Even more than CNN or Fox News, his aides felt that its pundits were extremely negative and unfair toward Sanders. Over the summer, Sanders and his top brass sat down with network president Phil Griffin in what MSNBC described as an off-the-record editorial board meeting.

“I thought we walked out of there without a good common understanding,” said Shakir. “My big point to them was this is Bernie Sanders, the human being. This is not the angry, yelling, finger-up-in-the-air Bernie Sanders as you guys often portray. Here he is, the human being. Talk to him.”

But any optimism was short-lived. “It just didn’t feel like it ever fundamentally changed,” said Shakir. “We tried that approach. Didn’t change.”

Mike Casca, an experienced operative who had worked for Bill de Blasio and Sanders in 2016, was brought onboard in September as the communications director to improve the operation, and he became a respected figure among the press corps that covered Sanders.

In August, Sanders’ campaign also talked with his former TV ad firm, Devine Mulvey Longabaugh, about returning. In addition to being behind the famous 2016 spot “America,” the business had served as a link between the Sanders movement and more mainstream Democrats and the press. But an aide said Sanders balked at what he saw as too steep a price, leading him to believe that the firm was more concerned with money than the cause.

“It was Bernie’s campaign that reached back out to us,” said Mark Longabaugh, a partner at the business. “We put a pretty standard contract on the table. It was not out of bounds in any way. It was in fact a smaller commission than we actually received in ’16.”

Despite the campaign’s attempts to deal with MSNBC, the network’s hosts and pundits blasted Sanders the day he won the Nevada caucuses — the type of campaign development that might have resulted in other candidates winning a slew of positive media. Chris Matthews compared Sanders’ victory in the caucuses to the Nazi invasion of France. James Carville said a Sanders nomination would be political suicide, and that Russia President Vladimir Putin was “the happiest person right now” about the news.

“The media between Nevada and Super Tuesday was more negative than anybody could have ever anticipated," said Jane Sanders. "That's something I hope the media would look at."

Shakir contacted Griffin after the show and demanded an apology for Matthews’ remarks, which Sanders was deeply offended by as a Jewish man whose family members died in the Holocaust. Matthews admitted on air it was a mistake and later parted ways with MSNBC on the eve of Super Tuesday.

But by then, the damage had been done.