Since her victory last summer over powerful Democratic Party incumbent Joe Crowley, Alexandria Ocasio-Cortez has been subject to relentless attacks from the right and center. She’s also become a hero to both the progressive left — which recognizes the democratic socialist congresswoman as a political challenger to the ruling elite — and many mainstream liberals captivated by her charisma and empowering personal story. Love her or hate her, nobody can deny that she’s emerged a singular force in American politics.

Rachel Lears’ new documentary film Knock Down the House winds back the clock, opening on a scene of Ocasio-Cortez midway through her congressional run, applying makeup at a bathroom mirror. She wonders aloud, “How do you prepare for something you don’t know is coming?”

The film follows four progressive women who ran primary campaigns against established centrist Democrats in the 2018 congressional midterms: Ocasio-Cortez in New York, Amy Vilela in Nevada, Cori Bush in Missouri, and Paula Jean Swearengin in West Virginia. None of them knew for certain what their chances were or the extent of the difficulty they would face. But they all knew one thing: the time had come for people like themselves — ordinary working-class people from diverse backgrounds — to vie for state power.

Vox calls the film a “liberal, feel-good movie,” and indeed the last half-hour is an emotional rollercoaster, brimming with tears and cheers. But the film is much more than that. It is a forceful polemic. It makes three arguments effectively: first, that working-class people can and should run for office; second, that while it’s not easy, it is possible to run successful insurgent campaigns against establishment politicians; and third, that there is something wrong with the Democratic Party.

The progressive political organizations Brand New Congress and Justice Democrats culled the featured candidates from a long list of crowdsourced nominees. It was important to these groups to identify potential candidates with typical jobs and relatable stories, people the film calls “political outsiders.” The theory, as Isra Allison of Brand New Congress says early in the film, is that “if we elect working people, working people can have representation in Congress. We can change the way we see government, and change the way we see politics in this country.”

The average congressperson has a net worth of nearly a million dollars and the average senator over three million dollars. Working-class people typically don’t see themselves as potential political leaders, and if they do find the inspiration and confidence to run, they don’t often have the personal resources to launch a competitive campaign.

The film is committed to a more expansive vision of who can be a politician. “Everyday Americans,” says Ocasio-Cortez in between footage of her donning latex gloves as she transports buckets of ice to her bartending station, “deserve to be represented by everyday Americans.”

In one scene, Paula Jean Swearengin drives through Coal City, West Virginia pointing out houses where people she knows have had cancer. Swearengin comes from a long line of coal miners, and many of her neighbors and family members have died young. She gestures to a vista scarred by mountaintop removal and says, “If another country came in here and blew up our mountains and poisoned our water, we’d go to war. But industry can.”

The film advances the theory that a political representative who has lived a typical working-class life in coal country, and has herself been exposed to industry-driven pollution and its toxic effects, is a superior representative of people dealing with those concerns than someone like Swearengin’s opponent, Joe Manchin, whose personal wealth is derived from the coal industry.

The principle holds for working-class black life in St. Louis. Cori Bush’s district in Missouri is where Mike Brown was killed by police, sparking Black Lives Matter protests across the country in 2014. The district is the state’s murder capital, and is devastated by poverty and mass incarceration. Its current representative, Lacy Clay, is black, but that doesn’t necessarily mean he can personally relate to his constituents’ struggles — in 2001 he took over the Congressional seat from his father, William Clay, who held it for decades starting in 1969.

Bush, a registered nurse, became an activist when she volunteered to provide medical assistance during the Ferguson protests. In one scene, Bush tells a group of constituents, “It’s gotta be about us, thinking about us, caring about us, speaking about us.” In another scene, when a black man whose family has always voted for the Clay dynasty pushes back about the Clays’ “seniority,” Bush responds, “But who does it count for? Is it definitely counting for us? Do we feel the seniority?” The us here is not just black people — it’s working-class black people, whose parents are not Congressmen but cooks or teachers or unemployed.

At a doorstep in Las Vegas, Amy Vilela describes herself as “someone who should not be able to run for Congress. I was a single mom. I was on Medicaid, WIC, food stamps.” The woman at the door nods vigorously in recognition. This is one of the film’s central contentions: that not only can average people can be political leaders, but that they make better political leaders than career politicians, because they understand the realities on the ground.

The film also makes a strong argument for mounting primary challenges to establishment politicians. The political machine relies on widespread popular resignation, a false sense of political immutability. But the foundation of the house is shakier than we think. “The entire New York political establishment, they have no idea what’s going on,” Ocasio-Cortez tells the audience at a a Democratic Socialists of America event. “This race is winnable. And don’t let anyone tell you any different, because the power out there, I’m telling you, is an illusion.”

The film brings a sober perspective to the difficulties of running an insurgent progressive campaign. One scene depicts Amy Vilela making fundraising calls from behind a laptop with an Our Revolution sticker on it: after a string of denials, she’s overjoyed when she can put one person down for a hundred dollars. Elsewhere, Ocasio-Cortez struggles to get ten times the required number of signatures, knowing that the political machine controlled by her opponent is likely to throw many of them out on technicalities.

But the film’s tone is hopeful: with old-fashioned organizing, the seemingly impossible becomes possible. The thesis is that while establishment politicians may have name recognition, professional connections, and personal money, that doesn’t mean they have people on their side. In fact, many of them are so habituated to paying their way to victory that they’ve forgotten how to speak and listen to constituents.

During Ocasio-Cortez’s race, Crowley was living full-time in Virginia, not New York. In one incredible scene, she debates a Crowley surrogate at a community center. Ocasio-Cortez condemns Crowley’s absenteeism, and tells the crowd, “For so long, we haven’t had these forums. The only reason we are here is because we organized for the first primary election in fourteen years.”

When the faux-debate ends, Ocasio-Cortez stays behind to talk to African and Yemeni immigrant constituents. Crowley’s surrogate is nowhere in sight. The message is clear: while Crowley had money and influence in abundance, he lacked basic organizing skills. With tireless canvassing and genuine community engagement, a young working-class woman from the Bronx could take on one of the most powerful Democrats in Washington.

Finally, the film levels a forceful indictment of the Democratic Party establishment — this at a time when the progressive base of the party is more antagonistic toward the party elite than perhaps ever before.

Amy Vilela got involved in politics after her daughter died, denied necessary treatment because she didn’t have health insurance. Inspired by Bernie Sanders’ vision for a Medicare for All system, she became an activist. She soon decided to run for Congress against Steven Horsford, a professional lobbyist turned Democratic congressman with a history of cozying up to insurance and pharmaceutical companies.

One telling scene takes place at a Democratic congressional candidate forum in Nevada. The moderator asks the candidates collectively whether they support various social justice causes, and they all unanimously raise their hands indicating that they do. But when the moderator asks them if they refuse corporate PAC money, only Vilela raises her hand — with a determined stare.

This is the crux of the film’s criticism of the Democratic Party establishment: it is unwilling and unable to represent working people’s interests because it is saturated with corporate money. Furthermore, it’s tightly controlled to protect the careers of corporate Democrats against a progressive insurgency. At one point in the film, it’s revealed that Joe Crowley himself was a major donor to Steven Horsford campaign. Party insiders look after their own.

Justice Democrats and Brand New Congress have a particular perspective on how to approach the Democratic Party. Their project is “to change the Democratic Party from the inside out.”

For socialists, this is an open question: is the Democratic Party salvageable, or do we need to form a new party dedicated to representing working-class interests against capitalist-class interests? Even if we see an independent party as an eventual necessity (a possibility that, to their credit, Justice Democrats explicitly entertains), the system is currently designed to repress third-party activity, making third-party campaigns a poor vehicle for mass politics in most scenarios. At present, progressives and democratic socialists don’t have a dedicated base big enough to stage an exodus into a new party formation, at least on a scale sufficient to overcome those deliberate obstacles. The short-term goal needs to be building that base.

For those of us who desire an explicitly socialist mass political party, candidates like Ocasio-Cortez, Vilela, Bush and Swearengin are creating ample opportunities for organizing toward that goal — even if, in the process, they risk offering false hope about the redeemability of the Democraic Party. They create those opportunities by condemning capitalist-class greed and raising working-class expectations.

Speaking of her daughter’s death, Vilela says with tears in her eyes, “No one in this great country should be dying because they don’t understand the intricate system of insurance.” And why is it so difficult to navigate? “Because the CFOs that work in that field are sitting there figuring out ways to make optimum profit for their shareholders.” She holds up her iPhone. “This is a commodity. My daughter’s life wasn’t.” This is what we need right now — a critique of capitalism, leveled in human terms, messaged to as many ordinary people as possible.

From a socialist standpoint, the film has one other tricky aspect. Its first thesis, that working-class people need to be represented in office, is undoubtedly true — but representation is not enough. As the case of Bush’s opponent Clay makes evident, racial representation in the halls of power is not by itself a solution to racial injustice. The same is true for class. While a politician may be more likely to understand working-class pain and hardship if they’ve experienced it firsthand, they will still be under immense structural pressure to compromise and capitulate.

Subjective understanding is only half the battle. The other half — indeed the greater half — is objective and structural, having to do with the balance of class dynamics in society at large. As the history of social democracy has repeatedly shown, personal allegiances are a poor match for impersonal social forces. The only way to ensure that a candidate with a high degree of subjective fidelity to the working class can resist the objective pressures imposed by capitalism is to organize people outside the state en masse.

“We meet a machine with a movement,” said Ocasio-Cortez, and it’s true. But the movement can’t be strictly electoral. The first job is to build a strong labor movement composed of working people most of whom will never will run for office — people who can, through collective action, bring the profit system to a halt in order to wring concessions from the ruling class. (Lears’ previous documentary, The Hand that Feeds, demonstrates that she knows full well the critical importance of the labor movement.)

We also need mass movements of ordinary people built around the demands that candidates like these hope to advance in a hostile legislature: Medicare for All, fully-funded public education at all levels, workers’ rights, climate justice, and more. Representatives like Ocasio-Cortez have little hope of achieving ambitious reforms that harm corporate profits, like the Green New Deal, without activists staging sit-ins and filling the streets in protest.

Still, an electoral movement for pro-worker representatives is a major component of the long-term project. Knock Down the House inspires hope that, at least on the electoral front, things are moving swiftly in the right direction, aerating the soil in which socialist ideas can take root and flourish.

“After 2016,” says Vilela’s field operations director Joz Sida in the film, “nothing is predictable. Nothing.” That’s exactly right. Insurgent democratic socialist Bernie Sanders nearly beat establishment boss Hillary Clinton. Hillary Clinton unexpectedly lost to long-shot Donald Trump. Nothing can be taken for granted, and we should mine that unpredictability for all it’s worth.