“Bernie! Bernie!” the crowd chanted in Council Bluffs, Iowa on the campaign trail last week. But Bernie Sanders demurred. “It ain’t Bernie, it’s you. It’s not me, it is us.” The crowd responded with a new chant: “Not me, us! Not me, us!”

A similar exchange took place at each of the two campaign kick-off rallies the previous weekend, first in Brooklyn and then in Chicago. In Iowa, Bernie gave a rationale for his response. “The truth is that the powers that be,” he said, “they are so powerful, they have so much money, that no one person, not the best president in the world, can take them on alone. The only way we transform America is when millions of people together stand up and fight back.”

No viable presidential campaign has ever been so encouraging of agitation from below.

Bernie is often compared to Franklin D. Roosevelt, but while Roosevelt inveighed eloquently against inequality, he was nowhere near as consistent in calling for for mass political activity from below. It was his contemporary, the socialist leader Eugene Debs, who spoke of the power of working people to change the world despite the considerable political advantages of elites.

“Employers, who are the beneficiaries of the wrong, have hitherto been able to crush, in most of the states, all remedial legislation,” Debs wrote, but “labor may be induced to unify, and taking the aggressive in politics, bring about the reform required.”

The language is old-fashioned, but the formulation is almost identical to Bernie’s in Iowa: an acknowledgement of the ruling class’s formidable power, paired with an insistence that ordinary people can break that power by uniting and fighting back.

In the few weeks since he announced his 2020 run, Bernie has made it clear that he plans to emphasize the importance of political activity outside the established channels of state power.

At his Chicago rally, the first speaker to appear before the crowd was Destiny Harris, an eighteen-year-old local Black Lives Matter activist. Harris is active with the No Cop Academy campaign, which aims to prevent the construction of a $95 million law enforcement training center on Chicago’s West Side, arguing that the city already spends far too much on policing and should spend that money on youth and community services instead.

But the project is strongly backed by Mayor Rahm Emanuel and the rest of the city’s political class. Opposition from elected leaders has become nearly unthinkable in Chicago — so much so that local alderman and Democratic Socialists of America member Carlos Ramirez-Rosa was expelled from the city council’s Latino Caucus as a result of his lone votes against the academy. Few local elected officials will touch the No Cop Academy campaign, yet Bernie chose a No Cop Academy activist to open up his rally.

Joining Harris on the bill was Ashley Galvan Ramos, a twenty-one-year-old anti-gentrification activist in Chicago’s Logan Square, a formerly working-class, Latino neighborhood that has gentrified in recent years at rapid speed. By inviting Harris and Ramos to the stage to make their cases to a captive audience of over twelve thousand people, Bernie was lending his platform to the construction of extra-parliamentary political movements. Chicago’s local movements against over-policing and gentrification were stronger when he left than when he arrived.

When he took the podium, Bernie gave a new speech, this one centering on racial injustice and detailing his own early political history. He focused on a time before he became a mayor, a congressman, a senator, or a potential president — when he was an activist with no formal state power. He spoke about coordinating a sit-in to protest racially segregated housing owned by the University of Chicago, where he was a leader of the campus chapter of the Congress on Racial Equality (CORE). And he also spoke about being arrested by police and bailed out by the NAACP after a civil disobedience action protesting racial discrimination in the Chicago education system.

“My activities here in Chicago taught me a very important lesson that I have never forgotten,” he said. “Real change never takes place from the top on down. It always takes place from the bottom on up.”

Bernie then spoke about traveling in 1963 to Washington, DC to attend the March on Washington for Jobs and Freedom, where Dr Martin Luther King — one of Bernie’s two biggest personal heroes, the other being Eugene Debs — gave his most famous speech.

Many Americans remember the line from that speech about not judging people by the color of their skin but instead by the content of their hearts. Few remember that King praised the “marvelous new militancy which has engulfed the Negro community” and warned that “the whirlwinds of revolt will continue to shake the foundations of our nation until the bright days of justice emerge.”

Because Bernie’s politics were forged in that era of mass protest, it comes as little surprise that he values extra-parliamentary politics on principle. But there’s a very good strategic reason for him to value grassroots left-wing and working-class movements as well. If he becomes president, he will need them to accomplish anything ambitious.

In a different, perhaps more ideal scenario, an openly socialist presidential candidacy would be the culmination of an intensive decades-long political project. The candidate would rise organically through the ranks of a dynamic and powerful organized Left. That Left would consist of, among other things, strong left-wing unions, innumerable community groups knitted into tight coalitions, and a mass political party with a democratic membership structure and credible means of candidate discipline. The candidate would emerge as the leader of a substantial movement made up of rock-solid working-class institutions.

But that’s not how things have played out. Instead, the socialist idea morphed in the late twentieth century from a powerful taboo to a tacit impossibility, unions were hollowed out and hamstrung, and the organized Left was placed on the back foot. Without a unified mass movement to represent, Bernie marched to the beat of his own drum for decades.

But in that time, stagnating wages and rising living costs have tested millions of people’s patience with the status quo. The 2008 financial crisis, Occupy Wall Street, and Black Lives Matter further eroded popular tolerance for business as usual, creating new openings for left-wing politics. In a happy historical coincidence, Bernie Sanders happened to have stayed politically consistent, to be in good health, and to be personally willing to provide electoral leadership to a movement getting back on its feet.

One problem with this sequence of events is that there are very few serving politicians who are sympathetic to Bernie Sanders’ politics, and even fewer who are also skilled at standing up to capitalists. He therefore can’t rely on many allies within the state to move major parts of his agenda through the legislature.

In the face of a Medicare for All proposal, for instance, the private insurance industry will inevitably use every tool at its disposal to “crush all remedial legislation,” as Debs put it, and most politicians will be inclined to cave.

The only way out of this unfavorable predicament is for a mass movement of ordinary people to exert its own pressure on politicians, rivaling the pressure exerted by capitalists. This can be accomplished in a variety of ways: political strikes that tank profits or halt the normal functions of society, disruptive mass protests, successful media campaigns that create new moods in the electorate and threaten politicians’ careers.

When Bernie says that he can’t deliver the needed reforms by himself, that he needs help from millions of people who themselves have no formal power, he’s not just flattering us. He’s insisting that extra-parliamentary movements are the key to political success. This is the underlying meaning of the slogan he has revived for his 2020 campaign: “Not Me, Us.”

While the scenario leading up to a viable socialist presidential candidacy may not have played out precisely as socialists had envisioned, it has one distinct benefit. In order to make change, Bernie will be forced to wield the office of the presidency in a very different way, using his platform to encourage rather than stifle mass action.

United Electrical Workers (UE) Local 506 went on strike this month at the giant Wabtec locomotive plant in Erie, Pennsylvania. Last week, Bernie’s campaign text-banked his contact list to turn people in the region out in support.

This outreach wasn’t a public relations stunt; in fact, there’s been almost no coverage of it in national media. Instead it was a powerful act of solidarity, demonstrating that while Bernie never hesitates to tweet his support for workers, his commitment runs much deeper than campaign optics. It’s about building the muscle of the working class in preparation for the struggles ahead.

At his kickoff rally in Brooklyn, Bernie invited UE 506 president Scott Slawson to speak to a crowd of thirteen thousand people. At one point during Slawson’s speech the crowd began to spontaneously chant, “Strike, strike, strike!”

That has, without a doubt, never happened before in any presidential campaign rally of recent decades. And if it’s any indication, then some people are ready to do what Bernie asks of them — not simply to support his vision of redistribution, democracy, and equality, but to fight for it.