In the week since the election, political pundits and everyone who didn’t vote for Donald Trump have been trying to wrap their heads around how he emerged victorious as president-elect.

Are the 60 million Americans who voted for Trump as ignorant, racist, and misogynistic as he proved to be during his campaign? Are they so disenchanted with the political establishment that they chose a con artist over a flawed but objectively more qualified candidate whose very name is synonymous with that establishment?

Of the many complicated factors that motivated the electorate, there’s evidence that the anti-establishment movement was a big one. We knew this when Bernie Sanders, an anti-establishment politician with very little name recognition, came close to beating Hillary Clinton during the primaries.

Early on, many progressive millennials admitted they preferred Sanders to Clinton. Now, that same demographic--joined by older supporters of both Sanders and Clinton—are marching to protest Trump’s election in cities across the country and calling for a political revolution.

They were marching down Manhattan’s Fifth Avenue on Tuesday when Becky Bond and Zack Exley, who spearheaded the grassroots volunteering efforts that helped Sanders surge ahead in the primaries, were at Civic Hall promoting their book, Rules for Revolutionaries: How Big Organizing Can Change Everything.

“We have to translate this energy into work that will actually blunt some of the worst abuses of the Trump administration, and also begin working to build the base of mass organizing that we’ll need to sweep the elections in 2018,” Bond said of the anti-Trump movement, while protesters chanted “not my president” outside.

I met the authors in a conference room at Civic Hall, ahead of a Q&A with Civic Hall co-founder Micah Sifry.

Bond worked for the CREDO—a mobile phone company that raised tens of millions of dollars for progressive groups—for 15 years before quitting her job to work full time for the Sanders campaign. Both authors are 46.

Having worked on Howard Dean’s presidential campaign in 2003, John Kerry’s in 2004, and Obama’s in 2008, Exley parlayed his knowledge of what made a campaign successful—particularly the Obama campaign’s strategy of forming “neighborhood teams” in battleground primary states—into efforts to mobilize and organize volunteers for the Sanders campaign.

Like Sanders himself, Bond and Exley aren’t interested in debating whether the Vermont senator could have beaten Trump had he been the Democratic nominee.

Yet they are certain the only way to fight the Trump administration now is to galvanize volunteers through “big organizing” for a revolutionary mass movement, just as they did for the Sanders campaign, pushing revolutionary progressive agendas through tech-enabled, peer-to-peer participation in politics.

Rules for Revolutionaries outlines 22 “rules” in chapters—from “The Revolution Will Not Be Staffed” to “People New to Politics Make the Best Revolutionaries”—and highlights major goals of big organizing: free public college, universal health care, an end to the drug war and the mass incarceration of racial minorities, and an anti-globalization industrial policy which, Bond and Exley argue, will create more jobs at home.

Many readers will recognize these goals from the Sanders campaign, but the book stresses that mass revolutionary organizing is bigger than the 2016 election: it’s what powered “virtually every transformational movement in US history from anticolonial rebellions up through the civil rights, women’s rights, and gay rights movements,” the authors write.

Indeed, the concept of big organizing isn’t new, but it’s especially appealing now to those who are fed up with establishment politics. There’s no big money in big organizing, and volunteers act as campaign staff.

In Rules for Revolutionaries, Bond and Exley explain that “big organizing is what populists used to simply call organizing but with the potential for much greater scale thanks to new and accessible technology for connecting people.”

Small organizing, by contrast, has risen recently with the liberal establishment’s attempts to address radical problems through incrementalist politics, putting power “in the hands of an increasingly small number of mega corporations and institutions,” they write.

Clinton’s campaign relied on small organizing, which Bond and Exley say works just fine when the goal is maintaining the status quo. But it’s not big enough to challenge the establishment.

“People are beginning to understand that the problems we face now, like climate change and racial injustice, are too big for incrementalist solutions,” Bond said on Tuesday. “We need to address these problems urgently and make huge changes before it’s too late.”

Both Bond and Exley noted that they were working on the fringe of the Sanders campaign in its early months, and that their big organizing tactics were considered so politically unorthodox at the time that it would have been irresponsible for the campaign to invest in them.

“The tragedy of these insurgent presidential campaigns is that hundreds of thousands of people want to come out and work but we don’t have the resources to put them to work,” Exley said, comparing the early grassroots movement of the Sanders campaign to a start-up with millions of customers and no product.

But their movement gained momentum over time: Sanders went from having only 3 percent name recognition at the start of his campaign to capturing 46 percent of pledged delegates—many of them pulled into politics for the first time—at the Democratic National Convention.

Kenneth Pennington, who was national digital director for the Sanders campaign, praised Exley and Bond’s big organizing efforts in an email to The Daily Beast.

“What Becky and Zack brought to Bernie 2016 was a strategy for organizing millions of volunteers that required fewer staff and less resources,” Pennington wrote, adding that they “built a network of largely self-sufficient volunteer teams that produced invaluable work for Bernie’s campaign.”

That invaluable work included 75,000 volunteer-run events around the country during the campaign, 8 million peer-to-peer text messages to supporters and voters, and 81 million phone calls to voters.

“Those kind of numbers only happen when you trust volunteers as leaders like Becky and Zack did,” Pennington wrote, remarking that their distributed organizing team “set the standard for how progressives should organize for decades and revolutions to come.”

Do they think their methods will be embraced in future presidential campaigns?

“It depends on who’s running the campaign,” Exley said, adding that veterans from the Clinton or O’Malley campaigns, for example, probably wouldn’t adopt a grassroots big organizing strategy. “They don’t know the potential of what we’re doing, so it won’t become standard.”

The key to changing the system, Exley and Bond argue, is understanding the importance of going for big goals that even progressive liberal politicians say are politically impossible.

And what of the progressive economists who argued that some of Sanders’s domestic economic proposals weren’t feasible?

In February, four former Democratic chairmen and chairwomen of the president’s Council of Economic Advisers wrote an excoriating letter to Sanders and Gerald Friedman, the source of the Sanders’s campaign’s numbers, calling out Friedman’s extremism and claims that “exceed even the most grandiose predictions by Republicans” and could “undermine the credibility of the progressive economic agenda.”

Responding to the letter, liberal economist Paul Krugman wrote in The New York Times that the Sanders campaign’s job projections and healthcare claims “aren’t just implausible, they’re embarrassing to anyone remotely familiar with economic history.”

Krugman noted that, under Sanders’s single-payer healthcare plan, health care costs would be disproportionately incurred by a small segment of the population.

“Paul Krugman is not a progressive economist,” Exley countered, arguing that economists have “shifted so far to the right” that liberals like Krugman are essentially promoting Reaganomics.

Bond concurred that ideology governs what people like Krugman consider feasible or possible—an odd assertion, given that Krugman and others who lambasted Sanders’s economic proposals have pushed for progressive reforms like raising the minimum wage.

“I don’t think there’s a strong empirical argument against making the changes we’re asking for,” she said, “it’s just a matter of prioritization.”

If the government can spend $20 trillion bailing out big banks and billions of dollars on wars in the Middle East, Exley and Bond argued, then it could certainly afford Sanders’s economic proposals.

To some, the core principles of mass organizing may seem similarly idealistic or counter-intuitive, like the idea that people are more likely to step up to the plate for game-changing issues—free college tuition!—than they are for incremental plans for change.

One can see how people new to politics—the best revolutionaries, according to Exley and Bond—would be more likely to rally behind those game-changing issues than more nuanced proposals.

“The people who are new come in with a sense of urgency and they don’t have bad ideas left over from the way they did it last time,” Exley said.

Today, many of those people are being asked by their friends on Facebook to protest Trump. How can they affect change through mass organizing now?

Bond cited the Black Lives Matter movement as an example of mass organization, and suggested that we appoint black leaders to deconstruct institutional racism while fighting for issues like income equality.

She also said that people need to be ready to act if, for example, President Trump mandated that all Muslims register. “We’d need to get millions of people to register as Muslims in solidarity,” she said, adding that—in the meantime—we should push for more American cities to be like San Francisco, a sanctuary city that protects immigrants from deportation.

Given that progressives already support these principles, we shouldn’t be surprised if an Occupy Wall Street-style, mass-organized movement arises in response to Trump’s presidency. And if the progressive anti-establishment movement that latched onto Sanders’s campaign pulls mainstream liberal voters into its camp, then Rules for Revolutionaries might become our generation’s political manifesto.