UPDATE: April 8 — Sen. Bernie Sanders (I-Vt.) announced he was dropping out of the presidential race.

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As Sen. Bernie Sanders (I-Vt.) prepared for the third Democratic presidential debate in mid-September, his campaign was publicly facing the problem of what to do about Sen. Elizabeth Warren (D-Mass.), the fellow progressive who was ahead of him in Iowa polls and was picking up national momentum.

But behind the scenes, Sanders’ aides were worried about someone else: former Vice President Joe Biden. Internal polling showed Biden was their main competition for working-class voters of all races ― particularly those in middle age who weren’t yet firmly in any candidate’s corner.

A few days before the debate, Sanders’ pollster Ben Tulchin and speechwriter David Sirota drove up to Boulder, Colorado, where Sanders and his inner circle had holed up to prepare for the event in Houston. The two aides demanded an audience with Sanders to discuss a memo they had drafted with senior adviser Jeff Weaver and campaign co-chair and former Ohio state Sen. Nina Turner, in which they recommended that Sanders draw clearer contrasts with Biden. They wanted Sanders to bring it up in his opening statement in the debate, when he would be able to control the floor uninterrupted and set the tone for the night.

Sanders, who felt Biden had treated him kindly in Congress, had always been reluctant to take a more aggressive approach. He was also attuned to the risk of blowback when a candidate goes on the attack in a crowded field. But he left Sirota and Tulchin with the impression that he was willing to give it a try. A senior aide even followed up with the pair, asking them to draft an opening statement for Sanders.

Senior aides familiar with the debate preparation taking place before Tulchin and Sirota arrived have a different version of events. Sanders had been warming to the idea of going after Biden in the preparatory sessions, but grew more tentative after the visit. He was skeptical of shaping his message based on the advice of any pollster, and had been growing frustrated with Sirota’s shoot-from-the-hip approach for some time.

Regardless, when the moment arrived, Sanders blinked. At the start of the debate, when ABC News anchor George Stephanopoulos turned to him for his opening statement, Sanders, appearing lost in thought, didn’t respond at first. It took a second prompt of “Senator Sanders” to get him to launch into his introductory remarks. Then, rather than take on Biden, Sanders delivered his usual denunciation of the shift toward an “oligarchic form of society where a handful of billionaires control the economic and political life of the country.”

His greatest strength is his greatest weakness, which is that his independence and stubbornness mean he is not agile enough to respond to shifting moods. Pro-Sanders progressive strategist

The moment encapsulated the frustrations of multiple groups of aides ― particularly Tulchin, Sirota and Turner ― who had pushed Sanders to contrast himself with Biden earlier and more consistently.

The flare-up over how aggressively to attack Biden, however, was just one of many schisms that plagued the Sanders campaign. Over the course of just 10 explosive days between the Nevada caucus on February 22 and Super Tuesday on March 3, that campaign cratered, with Sanders going from an unrivaled front-runner to a distant second-place contender, likely due to finish with far fewer delegates than he commanded in 2016.

HuffPost spoke to more than three dozen Sanders aides, allies and critics about why the progressive leader stumbled. Many of them requested anonymity to speak freely.

The answers they suggested are myriad. He failed to erect a campaign nimble enough to overcome the built-in challenges he was bound to face from a skeptical press corps and a hostile party establishment. He hung his electoral success on the relatively risky bet that he could both expand the electorate and do so in a way that would benefit him disproportionately. His staff feuded unnecessarily with Elizabeth Warren, and he failed to make inroads with older Black voters ― a repeat of 2016 dynamics. Perhaps most significantly, Sanders failed to expand his core bloc of support into a coalition capable of winning a majority, and he did not adequately prepare for the prospect that moderates would consolidate behind Biden. “There was a strategy to get to 30% and not to 50%,” one Sanders ally said.

Many of these shortcomings go back to a defining feature of Bernie Sanders’ political career: He is going to do it his way or not at all.

It was that stubborn, independent streak and a contempt for the normal political playbook ― borne of deeply held moral convictions ― that reignited a fearsome grassroots army and powered a shocking political comeback after a heart attack sidelined the senator in early October. In many ways, the mere fact that a 78-year-old democratic socialist who proudly refused to affiliate as a Democrat, even as he sought the party’s presidential nomination a second time, emerged as a primary field front-runner was nothing short of amazing in its own right.

But it was those same characteristics that undermined Sanders’ effort to translate his movement into a White House berth.

“His greatest strength is his greatest weakness,” said a pro-Sanders progressive strategist, “which is that his independence and stubbornness mean he is not agile enough to respond to shifting moods.”

Brian Snyder/Reuters Jeff Weaver, left, speaks with strategist Tad Devine at a Sanders campaign rally in April 2016. For Sanders' second run, Weaver would accept a smaller role and Devine would be gone.

A Campaign Makeover Creates A Vacuum

When Sanders began convening aides to discuss a second White House run in January 2018, Mark Longabaugh, a veteran Washington campaign consultant who ― together with partner Tad Devine ― was behind Sanders’ most memorable ads of the 2016 cycle, had some ideas on how Sanders could correct some of his weaknesses from last time around. Winning a larger share of the Black vote, most observers agreed, would be essential. In a memo he drafted, Longabaugh recommended that Sanders demonstrate a commitment to that goal early on by kicking off his campaign with a high-profile speech on racial justice in Chicago. (He would end up delivering a kickoff speech there, but it did not focus exclusively on race.) He also suggested that Sanders court the leaders of major labor unions ― officials who had shunned him the first time, despite the depth of support for Sanders among their members.

In several subsequent conversations, Longabaugh even recommended he consider formally affiliating as a Democrat. Sanders never seriously entertained the idea, according to a senior aide.

Longabaugh left Sanders’ team in early 2019, citing strategic differences with Sanders. His departure created something of a vacuum in the campaign for experienced operatives unafraid to challenge the senator, regardless of the potential consequences. The 2016 campaign was plagued by accusations that Weaver, then the campaign manager, had run an unprofessional operation and intimidated employees into silence. Weaver also presided over a campaign in which women felt that senior campaign officials did not adequately respond to sexual harassment allegations. In December 2018, women who worked on the 2016 campaign publicly demanded a meeting with Sanders to “discuss the issue of sexual violence and harassment on the 2016 campaign.” Weaver announced the following month that he would not be filling the top job for a second time.

Instead, Sanders tapped Faiz Shakir, a well-regarded progressive advocate and Capitol Hill veteran with little electoral campaign experience, as his campaign manager. Ari Rabin-Havt, another Hill veteran and liberal jack-of-all-trades, would become Shakir’s top deputy. Both men’s most recent experiences working full time on a presidential campaign was for John Kerry’s 2004 White House bid. (Sanders had hired Rabin-Havt to his Senate staff in 2017.)

What’s more, Shakir, like Rabin-Havt, had worked for former Senate Majority Leader Harry Reid (D-Nev.). And he added some ethnic and religious diversity to a campaign leadership team that Sanders and Weaver admitted had been “too white” in 2016. Shakir, the son of Pakistani immigrants, is, by all accounts, the first Muslim to head a major U.S. presidential campaign.

Still, Shakir and Rabin-Havt amassed many detractors inside and outside the campaign who claimed their lack of senior presidential campaign experience hindered them.

“In 2016, Sanders had people who had a lot of experience in Democratic campaigns … he pushed them out and replaced them with people who had no experience running campaigns at any level,” said a Sanders supporter and senior official at a progressive organization. “Those people gained purchase with him because they were not people who would critique his impulses.”

The supporter also noted that none of Sanders’ 2020 advertisements, all produced in house, rivaled the viral success of the “America” ad or anything else the campaign had produced in the previous election cycle.

But a senior campaign aide took issue with that characterization, saying Shakir’s role was much different.

“More than any other staffer on the campaign, Faiz was honest with Bernie and was willing to tell him things Bernie didn’t want to hear,” the aide said. “Frankly, that’s a rarity in politics.”

Like many people on the left, Sanders had always been suspicious of traditional campaign tools with big price tags, including polling. The progressive stalwart generally viewed polling as a suggestion that he campaign on anything other than his principles. In fact, candidates can just as easily use polling to decide how to frame positions and which ones to emphasize most.

Weaver, who served as a senior adviser in 2020, did his best to keep Sanders from jettisoning what was left of the traditional campaign infrastructure. When Sanders was not interested in conducting any more polling in May, Weaver threatened to quit unless he reconsidered, according to multiple campaign aides. Weaver’s ultimatum worked; the campaign funded new polls, helping Tulchin shape Sanders’ message in the campaign’s TV advertisements.

But Longabaugh’s departure still coincided with an aimless period for the campaign as Sanders wandered from one theme to the next ― often driving news cycles that took the focus away from his core economic message.

Sanders puzzled many politics watchers with a speech on “democratic socialism.” The speech itself sought to demystify the term, framing his agenda as an attempt to complete the work of FDR’s New Deal. But some Democrats questioned why Sanders would use a national media platform to reignite attention on one of the more challenging elements of his candidacy, particularly since he gave a nearly identical address during his first run in November 2015.

Around the same time, in other public statements, Sanders appeared to be deliberately casting his agenda as radical. When a Biden aide said in May that the former vice president would seek a “middle ground” on climate change, which the campaign later disavowed, Sanders turned “no middle ground” into a battle cry in speeches and on social media. The phrase became the mantra of a speech that Sanders delivered to the California Democratic Party convention in early June implicitly contrasting himself with Biden, who chose not to attend the event and a nearby candidate forum hosted by MoveOn.

The incidents in themselves likely did little to undermine Sanders’ bid. But they embodied a tendency to conflate the long-term goals of activists with the short-term goals of winning an election that would inform many of the campaign’s decisions.

“Elections are about organizing people where they are at,” said the senior official in a progressive organization, who emphasized their belief in the importance of long-term organizing to shift public opinion. “In the course of an election, indulging the impulse to teach people new ideas and illuminate modes of oppression they don’t yet understand almost always diminishes our chances of winning.”

Alex Wong/Getty Images Sanders campaign manager Faiz Shakir greets Jane Sanders at a March 3 rally. Shakir's critics believe his decision to regularly travel with the candidate hurt the campaign.

Mismanaging The Political Revolution

The campaign’s lurches from one theme to the next stood in stark contrast with the clockwork-like pace of the Warren campaign, which, at the time, was generating well-planned earned media coverage for its policy rollouts.

Sanders trusts a very small circle of trusted advisers and is slow to make decisions, particularly when it comes to considering potential changes in his approach. It’s a tendency that would later be evident in his relatively drawn-out response this month to the COVID-19 outbreak. Biden incorporated fears of the pandemic into his critique of Trump in late January; Sanders began blasting Trump for his response to the crisis about a month later.

Likewise, Warren rolled out her first plan to address the crisis at the end of January, and second, more detailed one, at the beginning of March. But while Sanders convened a roundtable to discuss the topic on March 9, he did not unveil a comparable policy plan until March 17, the day after his first head-to-head debate with Biden.

It did not help matters, according to people familiar with dynamics inside the office, that Shakir insisted on traveling frequently with Sanders, an unusual practice for a chief executive that left some staff grasping for instruction. Rabin-Havt, Shakir’s second-in-command, also accompanied Sanders on all of his travel. This resulted in some aides feeling that the campaign’s leadership was primarily occupied with maintaining their own influence and proximity to the senator rather than empowering and supporting the broader campaign.

Back at the campaign’s headquarters in Washington, Shakir and Rabin-Havt held senior staff meetings once a week, a rate that presidential campaign veterans describe as infrequent. (In recent months, Arianna Jones, a deputy campaign manager based in Washington, began instituting nightly senior staff calls.)

Campaigns are “hard to manage when you’re not sitting in your office with your team,” said Mike Mikus, a Pittsburgh-based Democratic campaign veteran.

Senior campaign aides say that Shakir traveled with Sanders in order to ensure that the campaign got approval for strategic decisions as smoothly and speedily as possible. Shakir was part of a small circle of trusted advisers on whom Sanders, who sometimes needed extra prodding, relied for guidance.

Critically, the campaign never so much as hired a rapid response director ― a standard tool in the modern campaign kit ― to spearhead efforts to beat back negative narratives about Sanders.

What we saw from the Elizabeth Warren campaign was that a progressive candidate could have a big competent operation. The Sanders campaign never had a similar, organized structure and that hurt them in the end. Rebecca Katz, progressive strategist

As a result, the campaign seemed perpetually on its back foot in response to attacks of one kind or another. Some of those news cycles included a ginned-up controversy over why Sanders was delaying until April the release of a decade of tax returns (other rivals who released theirs later did not face similar pressure), and whether, as Hillary Clinton alleged, he “got nothing done” in Congress (he co-authored the bipartisan Veterans Affairs reform legislation of 2014 and passed more amendments during GOP control than any Democratic colleagues in the House).

“What we saw from the Elizabeth Warren campaign was that a progressive candidate could have a big competent operation,” said Rebecca Katz, a progressive campaign consultant who endorsed Warren in January. “The Sanders campaign never had a similar, organized structure and that hurt them in the end.”

In the absence of a nimble communications operation, some aides and surrogates ended up crafting their own messaging that was at odds with the official campaign line.

Briahna Gray, a national press secretary for Sanders who joined the campaign after a career in law and a brief stint in journalism, spent many days tangling with his antagonists on Twitter, including a number of media figures. In one string of late September tweets ripping the Warren campaign, she appeared to back the campaign into a position of publicly blessing a newly contentious stance toward Warren that the campaign never followed through on.

Turner also sometimes initiated assaults on Sanders’ rivals that the candidate himself had not yet engaged in. Ahead of the November debate in Atlanta, for example, Turner took thinly veiled shots at former South Bend, Indiana, Mayor Pete Buttigieg, before clarifying that she did not speak for the campaign.

And Sirota, a journalist with Capitol Hill and campaign experience, launched a Sanders campaign newsletter “Bern Notice” that offered a disclaimer that the newsletter reflected his views and not those of the campaign. He was still admonished for using the newsletter to promote a January op-ed by Sanders-backing law professor Zephyr Teachout on Biden’s “corruption problem.”

The disarray beneath Sanders ― whether on the communications side, or elsewhere ― might have been less harmful if Sanders himself had a sharper grasp of the tools it took to make a campaign succeed.

But at times, he appeared to be penny wise and pound foolish. He was known to complain to aides about the number of advance staffers it took to erect his events, wondering why it was necessary to employ so many people just to put on rallies.

At the same time, Sanders was slow to staff up in Iowa, allowing Warren and Buttigieg with fewer funds to erect a more sophisticated field operation earlier in those states. He finally agreed in October to unlock funding to hire more staff, air TV ads and spend on other campaign priorities.

But after the flood gates opened, Shakir did not keep a close eye on the budget, according to multiple aides. When Shakir realized in mid-December that the campaign was burning through money too rapidly, he admonished senior staff to significantly scale back travel and other expenses in the hundreds of dollars.

The campaign would end up spending over $50 million in the final quarter of 2019 ― about one-and-a-half times the $34.5 million that it raised over that period.

Generally speaking, only presidential campaigns struggling to fundraise burn that kind of cash before January in order to raise still more money, according to Mikus. Otherwise, he said, campaigns generally amass funds to spend more heavily in January ahead of Iowa and the other early states.

“Given the amounts Sanders was raising, they should never have spent more than they were raising prior to the elections,” he said.

Of course, Sanders never encountered the budgetary problems endured by Warren and Sen. Kamala Harris (D-Calif.). Both candidates found themselves short on cash at key moments because of ill-advised investments early on in the campaign.

Top Sanders aides defend Shakir’s handling of the budget, noting that he entered the quarter with $33.7 million in cash on hand. That allowed the campaign to end the period with $18 million on hand even as it spent $50 million.

Kena Betancur/Getty Images Rep. Alexandria Ocasio-Cortez (D-N.Y.), left, endorsed Sanders at a rally in Queens on Oct. 19. Her support sparked a comeback for Sanders who suffered a heart attack weeks earlier.

The Comeback

In the fall of 2019, the Sanders campaign began working to correct some organizational soft spots. Shakir picked Mike Casca, a 2016 campaign veteran who went on to work for New York City Mayor Bill de Blasio (D), to run the communications team.

Although he never managed to enforce message discipline on his staff and surrogates, Casca got overall high marks from reporters for streamlining the campaign’s press shop. Sanders’ policy rollouts, in particular, went from haphazard to well-planned.

“He deserves a hell of a lot of credit for helping reboot the campaign,” said Jared Leopold, who ran communications for Washington Gov. Jay Inslee’s presidential run.

That same month, Shannon Jackson, a 2016 campaign and Senate office alumnus, took over the campaign’s shambolic New Hampshire operation. And in October, the campaign sent a respected press deputy, Bill Neidhardt, to lend a hand as deputy state director in Iowa.

Sanders’ heart attack at the start of October threatened to jeopardize any potential progress from those changes though, just as Warren was overtaking him in the polls. The Warren campaign sent dinner over to Sanders’ headquarters the night after he was hospitalized ― a gesture that campaign staff appreciated but also saw as an ominous sign about the campaign’s direction. Democratic voters immediately began telling pollsters that Sanders’ age and health were a source of concern.

A series of fortuitous events, however, transformed the heart attack from a near-death knell into an upward inflection point. Sanders returned to the national spotlight two weeks after the hospitalization for the debate in Ohio, turning in one of his strongest debate performances all cycle. A joke about how his support for marijuana legalization did not mean he had used the drug before appearing onstage gave a foretaste of the warmth and humor he would bring to campaign-trail appearances in the months that followed.

And of course, later that night, it emerged that Sanders had secured the endorsement of Rep. Alexandria Ocasio-Cortez (D-N.Y.), the most coveted progressive blessing of the presidential race. She went on to headline a comeback rally for Sanders two weeks later that drew the largest crowd of any campaign event all cycle. Her support shifted the narrative of Sanders’ campaign to one about his revival, and ultimately arrested the inroads Warren was making among some of the young and very liberal voters Sanders needed.

“The timing of it was amazing. Literally and figuratively the campaign was on life support,” said Tulchin, the campaign’s pollster. “It showed that the campaign was alive and well.”

There was also a lesser-known, but perhaps even more significant, element of Sanders’ October revival: He began airing television advertisements in Iowa.

Sanders’ decision to continue to fund polls enabled his pollster Tulchin to help decide which themes to hammer home in ads.

The first television ad, “Betrayed by Trump,” was a telling example. The 30-second spot highlighted Sanders’ core economic message of taking on a rigged economy propped up by political corruption. Notably, the spot did not use the phrase “Medicare for All,” a policy popular with Sanders’ base. Instead, the ad described Sanders as “leading the fight to guarantee health care.”

There was one revealing weak point in Sanders’ Iowa results. His poor performance in Iowa’s rural precincts would go on to foreshadow the white working class’s abandonment of his candidacy.

Some analysts speculated that Sanders’ preference for mega-rallies in big cities put him at a disadvantage relative to Buttigieg. For example, Sanders held fewer events in Iowa’s rural 1st and 4th congressional districts than any other candidate except for Warren.

“He let Pete Buttigieg run free in those communities and it was a huge benefit to Pete,” said Jeff Link, a Des Moines-based Democratic consultant not aligned with any candidate.

Unlike Buttigieg though, not all of Sanders’ Iowa schedule was in his control. Some smaller events that the campaign planned to have Sanders attend in Iowa’s rural communities as part of a bus tour in the second half of January fell through because of the need for Sanders to be in Washington to participate in the impeachment trial, according to multiple campaign aides.

Alex Wong/Getty Images Sen. Bernie Sanders (I-Vt.) addresses students at the University of Nevada, Las Vegas. He maintained his edge with young voters, but failed to make inroads with other groups.

A Failed Bet On Expanding The Electorate

After Sanders’ popular-vote victory in Iowa and narrow win in New Hampshire, some people in his orbit began to wonder whether the campaign would hobble into the nominating convention in Milwaukee in July with a bare plurality of the delegates needed to clinch the party’s nod on the first ballot. If so, they feared that failing to win a majority of delegates ahead of the convention could jeopardize Sanders’ road to the White House, since the Democratic elected officials and insiders ― known as “superdelegates” ― were free to vote however they pleased starting on the second ballot. There was reason to worry: Nearly 100 of the superdelegates explicitly told reporters they would stop Sanders if he arrived without an outright majority.

Sanders’ blowout win in the Nevada caucuses on Feb. 22 allayed some of those fears. The result proved Sanders was capable of garnering more than 40% of a state’s vote ― a step closer to the majority marker he’d need to avoid a convention-floor showdown.

But the talk of a brokered convention spoke to a flaw in Sanders’ underlying strategy that the campaign never effectively confronted: Their coalition was considerably smaller than in 2016 and would not be able to withstand a sudden consolidation among moderate voters.

Of course, Sanders’ professed theory of the case did not require him to muse about how he might reach voters outside his demographic and ideological comfort zones. That’s because he insisted that his fortunes rested on bringing in new voters. He planned to expand the electorate by increasing turnout among an allegedly untapped bloc of young and working-class voters with a progressive worldview.

“The mythical voter that stayed home, but if you just give them a progressive candidate, they’ll show up ― it’s a lot like the tooth fairy, you hear about it a lot, but you never see it,” Mikus said.

Sanders’ campaign strategy did not revolve around such a political feat exclusively. Behind the scenes, his TV ads were tailored to persuade voters not yet in Sanders’ corner and his field operation devised sophisticated techniques for speaking to those voters as well.

They walked away with the erroneous conclusion that their support was much wider than it was. Tenoch Flores, former California Democratic Party spokesman

But at the very least, Sanders publicly billed himself as the candidate most capable of juicing turnout. It doubled as an electability pitch for a November showdown with Trump: that Sanders alone is capable of generating the increased turnout among infrequent voters needed to ensure a general election victory.

It also justified the campaign’s apparent view that there were few if any left-wing policies it could adopt that would undermine Sanders’ success at the ballot box.

“It’s a comforting way to think about politics because that way, you don’t have to compromise,” said Ruy Teixeira, a public opinion expert at the Center for American Progress, who donated to Biden after his South Carolina win.

As a result, even when Sanders would win an early state, he suffered from critical coverage of his failure to increase turnout, implicitly undermining the unconventional case for his electability.

Overall turnout barely went up in Iowa. In New Hampshire, where Republicans and independents can vote in the Democratic primary, Sanders’ moderate rivals did better among first-time voters.

Across the country, the white working-class Democrats and independents that had formed a key part of Sanders’ coalition in 2016 were abandoning him. At the same time, turnout among the largely white, upper-middle-class suburbanites who powered Democrats’ takeover of the House in 2018 surged. Their impact was most apparent in South Carolina and the Super Tuesday states where those voters turned out in great numbers and broke decisively for Biden.

Sanders’ bet that he could either reassemble his 2016 coalition or expand the electorate reflected an overly generous interpretation of his strong performance in 2016, according to Tenoch Flores, a former California Democratic Party spokesman who donated to Warren’s campaign.

“They walked away with the erroneous conclusion that their support was much wider than it was,” Flores said. In 2016, “there was a sizable anti-Hillary vote mixed in with his core supporters.”

Michael Tullberg/Getty Images Rep. Jesús "Chuy" Garcia (D-Ill.) speaks at a Sanders rally in Los Angeles. Despite Sanders' strong Latino support, only two Latino members of Congress endorsed him.

A Front-Runner Without The Endorsements To Match

Endorsements rarely make or break a campaign on their own, but they can be an indicator of a candidate’s talent for the “inside game” of wooing colleagues. For a progressive outsider like Sanders, they also serve as a source of mainstream validation.

When Sanders ran for president in 2016, he won just three endorsements from Democratic colleagues in Congress: Sen. Jeff Merkley of Oregon, Arizona Rep. Raúl Grijalva, then-Ohio Rep. Marcy Kaptur and then-Minnesota Rep. Keith Ellison.

To expand the ranks of elected surrogates backing his bid this time around, Sanders tapped Analilia Mejia as his political director. Mejia previously served as head of the New Jersey Working Families Party and worked for organized labor. She had little prior experience working directly on a political campaign, but she had spent years spearheading issue campaigns and labor’s independent efforts for candidates.

The campaign started out strong, announcing a roster of congressional endorsers on day one that was longer than what Sanders had amassed for the entirety of his 2016 bid. Sanders named Rep. Ro Khanna, who represents Silicon Valley and is less associated with the populist left, as one of his campaign’s four original co-chairs. The other two members of Vermont’s delegation, Sen. Patrick Leahy and Rep. Peter Welch, backed Sanders from the outset as well.

By September, though, that figure had not risen. Later that month, notwithstanding Mejia’s professional connections, Sanders lost the contest for the national Working Families Party’s endorsement to Warren. Unlike Warren or former housing secretary Julián Castro, Sanders did not take the progressive group up on the opportunity to address the WFP’s key decision-makers in a private audience.

The endorsement raised the possibility that Warren would supplant Sanders as the progressive standard-bearer in the race.

A pro-Sanders progressive activist described feeling as though the Sanders campaign felt entitled to the support of left-leaning groups and as a result, did not treat activists as respectfully as Warren’s campaign. The campaign sought organizations’ input on multiple policy proposals just a day or two before their rollout, providing little time for input, and did not answer emails from activists on multiple occasions.

“The outward motto of the campaign was ‘Not me. Us,’ but the real motto seemed like ‘Everybody against us’ or ‘Just us,’” the activist said.

Ocasio-Cortez’s endorsement the following month quickly dispensed with that risk, though. Her blessing ― and that of her “Squad”-mates, Reps. Rashida Tlaib of Michigan and Ilhan Omar of Minnesota ― played a role in Sanders’ sweep of endorsements from other progressive groups and members of Congress in the months that followed.

In cases where the campaign knew an endorsement was not forthcoming, Mejia and her small team did what they could to prevent an endorsement of one of Sanders’ rivals. When it came to international labor unions inclined to endorse Biden, for example, the Sanders campaign organized local affiliates and groups of rank-and-file members to publicly express their support for Sanders or privately urge their union leaders not to endorse. It’s an approach that Mejia credits for limiting Biden’s accumulation of union endorsements. While the vast majority of unions got behind Hillary Clinton months before voters went to the polls in the 2016 cycle, Biden only got his second endorsement from an international union in late January.

But as wins in the first three states propelled Sanders’ campaign forward, the pace of his endorsements ― and the credibility they confer ― did not accelerate at the same rate.

The outward motto of the campaign was 'Not me. Us,' but the real motto seemed like 'Everybody against us' or 'Just us.' Pro-Sanders progressive activist

Given Sanders’ big win in Nevada on the back of his strong support among Latinos, it was particularly surprising that he didn’t subsequently pick up more endorsements from Latino lawmakers. Of the 38 members of the Congressional Hispanic Caucus, just two ― Ocasio-Cortez and Rep. Jesús “Chuy” García of Illinois ― would end up endorsing Sanders.

What’s more, Sanders only secured the endorsement of civil rights leader Jesse Jackson, his most prominent Black validator, after Super Tuesday, when Biden had gained unstoppable momentum.

Other would-be validators never came around. Grijalva endorsed Warren in August. Merkley, Sanders’ first backer in the Senate in 2016, has still not expressed a preference in the primary.

A major part of Sanders’ endorsement troubles stemmed from his own aversion to interpersonal politicking. By his own admission, he is “not good at backslapping” or “pleasantries” ― the kind of “bullshit,” as he put it, that typically helps lawmakers develop working relationships with one another and with other influential people.

The most glaring example was Sanders’ failure to seek the endorsement of House Majority Whip Jim Clyburn (D-S.C.), whose last-minute endorsement of Biden played a critical role in Biden’s big win in the Palmetto State. The likelihood that Clyburn, a leader of the party establishment, would ever have endorsed Sanders was exceedingly slim.

But it is impossible to know whether more assertiveness from Sanders might have discouraged Clyburn from coming out for Biden when he did or otherwise influenced his conduct.

Joe Darby, a prominent Charleston pastor who endorsed Biden in December, said he had met or received calls from Biden, Warren, Buttigieg and Sens. Cory Booker of New Jersey and Kamala Harris of California, but not Sanders.

“People will not always be able to do you good, but they are always able to do you harm,” Darby said. “When you pass by the Black political leadership in the state, the Black social leadership, they’re not going to talk good about you.”

Even when it came to Ocasio-Cortez, his biggest endorsement of the cycle, Sanders almost did not do the work needed to win her backing. While Warren had courted her incessantly, Ocasio-Cortez’s aides needed to ask Sanders’ team to have him call her to seek her support.

Sanders wound up squandering opportunities for other potential pickups as well. In Virginia, a Super Tuesday state where Biden ended up winning by 30 percentage points, the Sanders campaign failed to reach out to state Del. Marcia “Cia” Price, a young Black woman and the only state lawmaker to endorse Sanders in 2016. Price did not endorse in the 2020 race.

Del. Sam Rasoul, the state’s first Muslim lawmaker and an outspoken progressive who was unaligned in 2016, ended up endorsing Warren after she personally courted him for over a year. He only heard from members of Sanders’ team in the weeks before the election.

The Sanders campaign also failed to court J.D. Scholten, an Iowa congressional candidate who, with Sanders’ help, nearly unseated racist Rep. Steve King (R) in 2018. Scholten told HuffPost that he spoke to Sanders when the latter had announced his run and met with local campaign officials in July, but the campaign never formally pitched him on the idea and even failed to notify him that Sanders would be holding a rally in his hometown of Sioux City in January. Other candidates, such as Warren and Buttigieg, asked for his support and did several joint events with him.

“The two times I like Bernie the most is when I see him live in person and when Ro Khanna is talking about him. Both times, it’s a message that brings people in,” Scholten told HuffPost. “With just what I saw in our neck of the woods in Iowa, it wasn’t consistent with those two experiences.”

Mejia said she did what she could with a small political team and a candidate who was not always eager to court elected officials and union leaders.

“I accepted that I had the kind of candidate that would skip over the traditional power brokers and go straight to the workers,” she told HuffPost, emphasizing that it was a quality in Sanders that she deeply appreciated. “I created ways to work around it. Some of them worked. And some of them didn’t.”

Scott Olson/Getty Images Sen. Elizabeth Warren (D-Mass.), left, and Sanders, right, have a tense conversation after the Jan. 14 debate as Tom Steyer looks on. The two progressives' rift loomed over the campaign.

Friction With Elizabeth Warren

Warren has not spoken about her decision not to endorse Sanders. She has repeatedly expressed her dissatisfaction though ― during and after her campaign ― with Sanders’ inability to tamp down some of his online supporters’ vitriolic rhetoric and bullying behavior.

Neither spokespeople for Warren nor spokespeople for Sanders would discuss the details of Sanders’ overtures to Warren after she withdrew from the race on March 5.

Some Warren allies were reportedly frustrated that Sanders had not reached out sooner to develop a relationship with Warren before she dropped out, according to BuzzFeed News. BuzzFeed reported ― and HuffPost has confirmed ― that at least one Warren aide sought to begin informal conversations with the campaign after the Iowa caucuses, but made little progress developing a channel for communication.

For their part, top aides to the Sanders campaign told HuffPost that they had been in touch with Warren’s staff over non-endorsement-related matters through February and early March. Out of a desire to not be presumptuous, Bernie’s team never broached the topic of an endorsement until after her withdrawal. For the same reason, they also never entertained communication from people who were not Warren, or one of her senior aides, since they couldn’t be sure who spoke for the campaign. (The Warren campaign declined to comment on the matter.)

Ady Barkan, a prominent Warren supporter who is dying from ALS, was one of the Warren allies who reached out to the Sanders campaign about brokering talks between the two camps, according to two people familiar with his efforts. He began contacting Sanders aides and surrogates two months before Warren’s withdrawal in early March.

The Sanders campaign said it had not received any communication from Barkan about Warren prior to Super Tuesday. A spokesman for Barkan declined to comment on the matter.

The cooling of Warren’s relationship with Sanders began long before that. CNN reported the day before a mid-January debate that Sanders had told Warren in a private December 2018 conversation that he thought a woman could not win the presidency. Sanders immediately denied it.

Initially, the report cited anonymous sources, and the Warren campaign declined to comment on it one way or another. In that void, Shakir denounced the report as a “lie” in a CNN interview. He added: “We need to hear from her directly, but I know what she would say that it is not true, that it is a lie.”

Instead, shortly after Shakir’s interview aired, Warren said that the CNN report was true. Shakir was more nuanced in subsequent comments. But Warren allies still blame his initial reaction for poisoning the well between the two camps.

The following night, at the final debate before the Iowa caucuses, tensions worsened. During the debate, Warren and Sanders stuck to their contradictory accounts of the private conversation. Afterward, Warren angrily refused to shake Sanders hand, accusing him of calling her a “liar on national TV.”

The incident had an immediately negative effect on the relationship between the two campaigns. The day before the CNN report, Shakir had proposed to Warren deputy Dan Geldon that the campaigns split the cost of a charter plane back to Washington after the debate so they could chat. Both Sanders and Warren needed to be back to participate in the impeachment trial and Sanders’ campaign had already reserved the plane. Geldon spoke favorably about the idea to Shakir, but he stopped responding to Shakir’s messages after the CNN story and the ensuing war of words, according to a Sanders aide familiar with the exchange. (The Warren campaign declined to comment on that incident as well.)

The Sanders campaign also believes that the incident inflicted permanent damage on Sanders’ candidacy. Nationwide, Sanders’ support among women dropped by 10 percentage points in the wake of the dustup, according to senior Sanders aides. The aides believe the campaign was able to limit the damage in the early states where it had been on the ground for months, but maintains that it hurt Sanders on Super Tuesday.

eremy Hogan / Echoes Wire/Barcroft Media/Getty Image Joe Biden celebrates his win in the South Carolina primary on Feb. 29. Several of Sanders' advisers wanted him to contrast his record with Biden's earlier and more consistently.

No Plan For The Biden Surge

On the eve of the South Carolina primary on Feb. 29, few would have predicted Biden’s widely anticipated victory all but enabling him to wrap up the nomination in one fell swoop. Biden’s 30-point win over Sanders prompted his moderate rivals Buttigieg and Sen. Amy Klobuchar (D-Minn.), as well as former contender, former Texas Rep. Beto O’Rourke, to get behind his bid almost immediately. The ensuing two days of positive wall-to-wall TV coverage, including live footage of Biden’s rallies, amounted to $72 million worth of media attention.

Even former Senate Majority Leader Reid, whose endorsement Sanders had been courting, got behind Biden the day before the Super Tuesday contests on March 3. Reid informed his former aide Shakir a day before he announced the decision.

The endorsements and the positive attention that followed propelled one of the most abrupt turns of political fortune in decades, setting Biden up for big wins on Super Tuesday despite his lack of campaign infrastructure. That kind of sudden, tidal change would catch any candidate by surprise.

At the same time, the Sanders campaign’s failure to plan for at least something along those lines was “a fundamentally naive proposition,” according to the senior progressive organization official supporting Sanders.

The campaign was woefully unprepared for the size of its loss in South Carolina. Sanders’ internal polling showed him within single digits of Biden, according to a Feb. 27 email obtained by The New York Times.

And within “Bernie World,” Sanders’ broad circle of formal and informal advisers and allies, there were conflicting ideas about the best way to shore Sanders up against such an unforeseen avalanche. Sanders never fully committed to any one of them.

Campaign advisers, including Sanders’ closest aides, pressing for him to take a more confrontational approach to Biden succeeded in getting Sanders to go along only some of the time. For example, Sanders never once used Biden’s comments to donors at a June fundraiser that “nothing would fundamentally change” for them under his presidency. Aides drafted language for Sanders to use in his opening statement during the first debate in June, but he never ended up using it.

On some specific occasions, like Teachout’s and Turner’s respective op-eds blasting Biden for corruption and lack of respect for Black civil rights, Sanders’ lack of trust in Sirota again played a role in stepping away from those lines of criticism. Sanders suspected that Sirota had been involved in authoring the columns, prompting him to reject the arguments, according to aides familiar with the matter.

Sirota had, however, informed Shakir and other senior aides about the Teachout op-ed ― albeit in passing ― a couple days before it went live, according to multiple aides. Those staffers also said that Sanders had read and approved Turner’s op-ed before it went to print as well.

Sanders only fully committed to contrasting himself with Biden after Biden took decisive control of the race on Super Tuesday when he won 10 of the 14 states in contention — a moment when it was too late for Sanders to revive his fortunes. The following day, March 4, Sanders began airing television ads attacking Biden. A spot targeting Michiganders ripped Biden for his support of NAFTA and other international trade agreements. And a spot targeting Florida voters that Sanders had approved in January for use on social media, but not TV, blasted Biden’s past support for Social Security cuts.

The late arrival of those ads “probably was an error,” Mikus said. “Negative attacks often work. And maybe it is a different race if it started earlier.”

Another group of Sanders allies led by Khanna, Weaver, actor John Cusack and former nurses union leader RoseAnn DeMoro, argued that Sanders could better appeal to mainstream Democratic voters if he made a concerted effort to cast his policies as a return to the party’s New Deal-Great Society roots.

Khanna modeled the effort with a series of TV appearances promoting Sanders as an “FDR Democrat.” He also used his public appearances to highlight Sanders’ legislative accomplishments, such as the 2014 VA reform bill.

At least one Sanders ad cast the Vermont senator’s big ideas as part of a tradition of ambitious American thinking exemplified by John F. Kennedy’s mission to put a man on the moon.

But in other key ways the campaign never embraced recommendations that they tailor Sanders’ rhetoric to better appeal to voters outside his base. Sanders, for example, did not incorporate FDR into his regular stump speeches or debate appearances. In the New Hampshire debate in early February, two candidates mentioned FDR: Biden and Klobuchar.

The lack of interest in promoting Sanders’ legislative record was especially remarkable, since Sanders had run television ads promoting his work with then-Sen. John McCain (R-Ariz.) on Veterans Affairs reform during his 2016 run.

This time around, the campaign did not tout his legislative accomplishments on TV. It did produce a 3-minute video in November that described how Sanders got the nickname the “amendment king” for passing the most amendments of any member of the Democratic caucus under the Republican majority from 1995 to 2006. Currently the video has under 37,000 views on YouTube. A digital video highlighting Sanders’ work on VA reform that the campaign released around the same time garnered under 26,000 views on YouTube.

Instead, after a victory in Nevada that solidified his status as a front-runner, Sanders continued to rail against the “Democratic establishment.”

“If you constantly describe yourself as marginalized, people start to think of you as marginalized and that maybe you shouldn’t be in charge,” said the pro-Sanders progressive strategist.

A post-Nevada appearance on CBS’ “60 Minutes” that the campaign specifically hoped would help make him seem presidential and humanize him for older voters turned into a debacle that would suck up precious oxygen in the days leading up to the South Carolina primary. Host Anderson Cooper asked Sanders about past comments defending elements of Cuban dictator Fidel Castro’s governance. In the interview, Sanders reiterated his belief that while Castro’s authoritarianism was reprehensible, his government had made laudable gains in literacy and health care.

Sanders’ nuanced view of the Castro government is common on the activist left. But notwithstanding Barack Obama’s similar comments as president, it remains a third rail for presidential candidates given the strength of the anti-Castro Cuban exile community in Florida. Sanders nonetheless employed identical rhetoric in subsequent media appearances, prompting Florida Democrats in particular to condemn Sanders and warn that his remarks amounted to preemptively conceding the Sunshine State to Trump.

“That was a moment where you could paint a picture for voters that you could lead the most powerful economy and military in the world and instead you were dogged with three days of whether Fidel Castro’s literacy program was good or not,” the pro-Sanders strategist said.

Salwan Georges/The Washington Post/Getty Images Sanders campaign co-chair Nina Turner, right, played a key role in South Carolina operations. Some of Sanders' local endorsers lamented the campaign's reliance on national figures.

Losing Older Black Voters — Again

Sanders did famously poorly among middle-aged and senior Black voters during his 2016 run. Hillary Clinton’s advantage with the Democratic voting bloc helped her win the Southern states by enormous margins, contributing to her accumulation of an insurmountable delegate lead.

The Vermont senator put in work to help change that for his second presidential run. He formed deeper relationships with progressive Black leaders like Rev. William Barber in North Carolina, endorsed several up-and-coming Black candidates for public office, and when he launched his campaign, made sure his campaign staff was racially diverse. He began incorporating racial justice more explicitly into his speeches, calling out a “racist and broken” criminal justice system and decrying the racial wealth gap. He also emphasized his commitment to naming a White House cabinet that reflected the diversity of the country.

In South Carolina in particular, Sanders took steps to signal that he would be mounting a competitive bid for the state. He visited the Palmetto State several times in the period between his runs, including a Medicare for All rally in Columbia in October 2018 and meeting with the state legislature’s Black caucus in January 2019.

Sanders tapped Turner, a Cleveland native and his closest Black confidante, to serve as his political emissary in the state. She began courting endorsements for Sanders early in 2019, helping him line up support from nine state lawmakers ― all of them Black. Sanders himself would go on to hold 70 events in the state over the course of his run.

But behind the scenes, the campaign was not investing the kind of resources in the state to indicate that it was a priority on par with other early states. The campaign spent just over $1.1 million on television ads in South Carolina in the month before the state’s primary, compared with a $6.9 million investment in ads in Iowa that funded over eight times as many ads over a four-month period, according to data collected by Kantar Media/CMAG.

“The fundamental challenge for the progressive movement is to build a much deeper alliance and relationship with the African-American community,” said Khanna. “There is no path to the nomination without African-American voters, nor should there be.”

The operation it did have on the ground in South Carolina suffered from mismanagement that rose to the surface when the campaign fired state director Kwadjo Campbell in November. At one point, Turner considered moving to South Carolina to embed permanently in the state’s campaign headquarters.

“It had a lot of challenges,” Turner said. “It was very hard from beginning to end.”

Some of Sanders’ local Black backers were troubled by the smaller role that the campaign felt they afforded them relative to Turner and an array of left-wing Black Sanders allies from outside the state ― a cast that included philosopher Cornel West, film star Danny Glover and former Berkeley, California, Mayor Gus Newport.

Turner, for example, rather than a local lawmaker, authored the January op-ed in a state newspaper blasting Biden’s record on civil rights matters.

One state lawmaker who endorsed Sanders expressed frustration with the campaign’s unwillingness to provide political support for lawmakers who were in swing districts and faced political blowback for endorsing Sanders in such a conservative state. The legislator noted that the campaign’s literature in the state seldom featured images of the state lawmakers alongside Sanders. Other elected officials, the lawmaker claimed, reconsidered the possibility of endorsing Sanders when they saw how little the campaign took advantage of, and elevated, its endorsers.

“The motto was ‘Not me. Us,’ but sometimes the feeling of ‘us’ became questionable,” the lawmaker said.

Turner conceded that the campaign only included the state lawmakers on one mailer, but noted that the campaign featured them in radio ads as well.

The campaign accepted the state lawmakers’ support with the understanding that they had “endorsed the senator because they really believed in his vision and his mission,” she said. “There were no roadblocks in their way to work with the campaign team in South Carolina to do what was necessary in their districts.”

In the end though, Sanders’ posture as a left-wing candidate likely did more to hurt his chances among South Carolina’s older Black voters than any single decision his campaign made.

Older Black Democrats, especially in the South, typically prioritize a Democrat’s electability above all else, since they believe protecting the freedoms they have won depends on keeping Republicans out of power, according to Darby. Biden’s perceived electability vis-a-vis the more radical Sanders was thus a critical factor.

Although Sanders racked up wins in the first three states to vote, he never managed to convince Black voters in South Carolina that he was the strongest contender against Trump in November. Clyburn’s endorsement of Biden three days before the primary was particularly powerful in this respect, according to polling.

“If the house is on fire, you put out the fire first, then you figure out what to do with the house,” Darby said. “I think Joe was the best person to put out the fire.”

CORRECTION: An earlier version of this story omitted then-Rep. Marcy Kaptur from the list of members of Congress who endorsed Sanders during his 2016 run.