Eight years ago on a Saturday morning in September, a few hundred New Yorkers marched to Manhattan’s financial district and set up a defiant encampment on Wall Street’s doorstep.

Three years earlier, millions of Americans had lost their savings, their pensions, their jobs, or their homes in the 2008 financial meltdown. Yet no major Wall Street executives went to prison for their role in the debacle. Indeed, the loudest proponents of market liberalization and financial deregulation—the very policies that led to the crash—used the catastrophe to consolidate their own wealth and power.

Despite this institutional failure to hold anyone accountable for the 2008 financial meltdown or address the causes of one of the worst recessions of all time, no one in the professional political class saw Occupy Wall Street coming. The movement’s unlikely explosion shocked the political establishment. GOP strategist Frank Luntz said he was “frightened to death” of the effort. House majority leader Eric Cantor decried the “growing mob” of Wall Street protesters.

Meanwhile, Democratic Party leaders scrambled to figure out how to relate to a movement that was picking a popular fight with corporate power that party elites had been avoiding for decades.

For 30 years, Democrats parroted Republican talking points about “free trade” and “welfare reform.” They failed to muster a coherent counterstrategy to the GOP’s dog-whistle racism and culture war, passed devastating trade deals like NAFTA, and marched in line on the disastrous Iraq War. They turned a blind eye as big money corrupted the American political system and finance capital rewrote the rules of the economy. For decades, the party’s leaders neglected to fight visibly and vocally for everyday working people—urban and rural, white, black, and brown—who had once been the party’s core base.

Barack Obama ran a remarkable insurgent campaign in 2008, outmaneuvering first the Democratic Party’s old guard in the primary, then beating McCain and the GOP. But rather than holding on to that anti-establishment momentum, Democrats squandered one of the biggest opportunities in the party’s history. Within the first weeks of the Obama administration, culpable bankers and Wall Street executives could have been paraded in handcuffs before the American people. The president and Democrats in Congress could have called out the unfettered greed of Big Insurance and Big Pharma to frame a popular health care fight. But instead of challenging powerful culprits, the Obama administration opted to appease them, packing the new administration with Wall Street executives and making backroom deals with the insurance and pharmaceutical companies.

Unsurprisingly, the GOP pivoted into full-throttle obstructionism, combined with fomenting and harnessing racism against the nation’s first black president, before he was even sworn in. This posed a serious challenge to the new administration.

But the job of a political party is to outmaneuver opponents and overcome obstacles. The fact that Democrats didn’t, despite a clear mandate, control of every branch of government, and popular support, is indicative of what’s fundamentally wrong with their approach to politics.

By abandoning the populist spirit that had just won them governing power, Democrats left a vacuum that conservatives filled with haste. Ironically, after years of conservative attacks against the institutions that once gave voice to working people, it was the radical right, via the Tea Party, that was initially able to consolidate dissatisfaction with the status quo into political power following the crisis.

Despite the fact that it was largely funded by the billionaire Koch brothers, the Tea Party managed to claim the mantle of anti-establishment politics in a moment when the nation’s mood was profoundly anti-establishment. Critical to the Tea Party’s credibility as political “outsiders” was running an open insurgency against GOP incumbents; their biggest takedown, House Speaker Eric Cantor. And key to the Tea Party’s numerous victories was keeping Democrats and the Obama administration on constant defense in a time when the latter were positioned to accomplish New Deal–scale reforms.

It wasn’t until the fall of 2011, nearly three years later, as the Tea Party’s momentum was waning, that a few hundred audacious young people set up camp in Wall Street’s backyard. They did something the old-guard Democratic Party had refused to do; they named the real culprits of the economic crisis: the rigged financial system, corporate oligarchs, and the bought-and-paid-for politicians that were doing the latter’s bidding.

Then, in 2016, populist strains that grew out of the Tea Party and Occupy movements reemerged in two presidential campaigns—those of Donald Trump and Bernie Sanders—representing two profoundly different visions for America.

The Democratic establishment understood Bernie Sanders about as well as it understood Occupy Wall Street. Senator Sanders had been fighting for the 99 percent long “before it was cool.” For decades, as elites declared that there was no alternative to unfettered capitalism, Sanders stood up for working families and exposed the rapacious greed of powerful corporate interests.

Unlike Sanders, Democratic leadership shied away from popular fights with Wall Street and giant corporations, ceding populist territory that Donald Trump was able to exploit. And the DNC helped stack the deck against Bernie in favor of a candidate who epitomized the out-of-touch political class. Donald Trump campaigned on a gamble that a candidate with an enthusiastic base could defeat a candidate with an ambivalent one. His narrow victory in 2016 proved that it was possible, and shows why Sanders is such a formidable threat to Trump in 2020. (Full disclosure: I am married to the national field director of the Bernie Sanders 2020 campaign.)

First, Sanders has a huge base of support. His political momentum is organic, and not just a reaction to Trump. This will be essential for going head-to-head with an opponent who so masterfully manipulated the media environment in 2016, to the point where Democrats mostly acted as unwitting reactive characters in Trump’s script. Even more important, Sanders’s approach to politics is laser-focused on bringing disaffected Americans into the political process.

The Bernie 2020 campaign has already activated hundreds of thousands of supporters, boasting the largest number of volunteers and small donors of any campaign. It’s not even close: In its map of campaign donors, The New York Times had to make two versions, one including Sanders’s donors and another not, in order to be able to view the other candidates relative to one another.

Bernie’s path to victory does not involve cozying up to the people at the top. He’s not holding fancy fundraisers in the Hamptons, or promising wealthy donors that “nothing would fundamentally change” when he is elected president—as Joe Biden recently did. Sanders understands that when politics becomes an exclusive clubhouse, it’s up to everyday people to bust down the door. When he calls for a “political revolution,” he means it.

This is the heart of what sets Sanders apart from every other candidate, even those who embrace many of his policies. Sam Adler-Bell recently explained the difference between Elizabeth Warren’s “I have a plan for that” mantra and Bernie’s “Not me, us” ethos. The key is that “Warren’s plans can be presented as the product of elite expertise,” whereas “Bernie’s outward allegiance to popular movements over political elites is a provocation in a way Warren’s appeal to ‘the best policies’ is just not.”

We need those popular movements to win. The reality today is that Americans can’t get good policy without a powerful force applying pressure from the outside. Everyone knows the GOP will fight tooth and nail to defeat any policy that would protect workers, rein in Wall Street, or tax the wealthy. Considering the well-oiled machine of GOP obstructionism of the past 10 years, it is beyond naive to imagine any Democratic administration accomplishing anything meaningful in the absence of a massive organized force that is applying consistent grassroots pressure.

Sanders’s policy proposals have changed the terms of Democratic debate. But he also understands that it’s just not enough to have good proposals. The reason that government has failed working people for the past four decades is not some shortage of good policy ideas. It’s not even that our elected leaders have lacked political courage (though for the most part they have). The fundamental reason is that working people have lacked political power.

There’s only one campaign with a plan to confront this central problem, only one campaign that has demonstrated an ability to inspire and organize a massive enthusiastic base of millions of voters, small donors, and volunteers, predominantly from the working class. And that’s the campaign of Senator Sanders. Bernie’s strategy is to organize working people into a formidable political force. He understands that whatever the problem, whatever the crisis, no policy plan is worth a damn if it’s not built upon the cornerstone of people power.

And it’s working.

Sanders is winning key swaths of voters who are essential to Democrats’ taking back the White House. Most obvious is Sanders’s overwhelming popularity among younger voters. What about voters of color though? Despite a media narrative about his supposed struggle to court such voters, a recent Pew Research poll found that Sanders is the only top-tier candidate whose supporters are majority (51 percent) people of color. And poll after poll show Sanders’s support to be overwhelmingly from working-class voters, a demographic that used to be the Democratic Party’s center of gravity.

The question is: Will the old-guard Democratic Party mess it up again? There’s reason for optimism. Today, thanks to a new generation of political candidates and office holders, Sanders is no longer a lone voice in the political wilderness. In 2018, Alexandria Ocasio-Cortez famously ousted 20-year Democratic incumbent Joe Crowley by elevating the interests of working people and calling out the predations of the ruling class. Ocasio-Cortez was sworn in alongside several other progressive freshman House members who have brought with them unprecedented diversity, dynamism, and popular support from young people.

“That’s like five people,” Speaker Nancy Pelosi said dismissively, trying to diminish the rise of the insurgents. But it’s hard to deny that “the Squad” and hundreds of newly elected progressives at every level of government across the country have become the locus of momentum and vision in today’s otherwise milquetoast Democratic Party.

Eight years ago Occupy Wall Street changed the national conversation and put the “1 percent” on defense. It was an important step, but, of course, Wall Street did not roll over and accede to our demands. Occupy hadn’t yet developed the capacity needed to translate its street-level momentum into political power.

So the crisis has only gotten worse. Inequality is even more severe, thanks in large part to the Trump tax cut. Wall Street and billionaires have further consolidated their control over our political system. Campaign finance laws, let alone enforcement, have become a joke.

Occupy gave the country the shared vocabulary of the 99 percent and the one percent. Bernie Sanders is harnessing this profound shift in political common sense, and channeling it into a vehicle for achieving national political power.

Senator Sanders can win because he understands that when you stand up and fight for working people, you give people real motivation to turn out. Millions of Americans believe in Bernie’s message: that health care is a human right, that the minimum wage must be a living wage, that college must be affordable, and that we must address the climate crisis and rebuild our economy in the process. By standing up consistently to powerful interests, Sanders is generating enthusiasm from voting blocs that the Democratic Party has been bleeding out for decades. He’s building the kind of force we need not only to win the nomination and then the White House, but also to accomplish a bold agenda for working people under a Sanders administration.

Politics is broken. The people who broke it aren’t going to fix it. It’s up to us to build the next phase of the movement that started in Zuccotti Park. It’s up to us to occupy the White House.