Bernie Sanders lost the fight in 2016. A decade later, he won the war.

In 2016, two populist revolutions threatened to remake American politics. Donald Trump’s conquered the Republican Party and delivered him the presidency. Bernie Sanders’ fell short against Hillary Clinton but introduced a populist economic vision that, at the time, much of the Democratic establishment dismissed as politically impractical.

Ten years later, Trump and MAGA were hit with a devastating midterm repudiation, as candidates across the country in blue and red states echoing versions of Sanders' message broke through in places that once seemed beyond Democrats' reach.

Sanders, as cantankerous as ever, isn’t surprised.

“If you're asking me, am I shocked by that? That the argument about economic justice and taking on oligarchs and fighting for the working class is working in Texas, is working in Ohio, is working in Montana, is working in Florida, is working all over the country — no, I am not shocked,” Sanders said in an interview Wednesday, fresh off over 20 rallies in October alone. “That is what I’ve always believed.”

Sanders’ laser focus on economic populism in 2016 faced criticism from his own party during his contentious primary against Clinton for being too dismissive of identity politics — often couched as his lack of support among Black voters. Now, his brand of relentless focus on corporate and billionaire election interventions and income inequality proved a winning formula not only for Abdul El-Sayed in Michigan, but for James Talarico in Texas, Sam Forstag in Montana and Rebecca Cooke in Wisconsin.

“Bernie normalized the kind of campaigning that really is about making a direct appeal to working people,” El Sayed told POLITICO. “Wherever I went in Michigan, there are people who remember Bernie 2016 and Bernie 2020 — we stand on the shoulders of giants.”

Given the booming results Tuesday and the breadth of wins for the left, Democrats will test whether they can avoid the same pitfalls that ultimately dogged them following their last major win in 2020 with Joe Biden’s blue-collar charm at the top of the ticket, after which the party gradually slipped back down the culture war slope.

To avoid that, Sanders said the party can do both, but that Democrats need to have the “courage” to focus on the day-to-day needs of working families, no matter what the billionaires funding the Democratic Party say.

“It's not either or. You can fight against bigotry and discrimination, but you have got to have the courage,” he said. “The courage now to say to the billionaires who are funding the Democratic Party: ‘Thank you very much for your help, but right now we are going to focus on the needs of the working families of this country, whether you like it or not.’”

Sanders’ reach is perhaps nowhere more evident than in New York City, which has emerged as the mecca of American progressivism, where Mayor Zohran Mamdani — once a Sanders-endorsed local official — is now perhaps the heir-apparent to Sanders’ progressive mantle.

The man behind Mamdani's seismic rise, progressive wunderkind Morris Katz, had more than most on the line this week. After his top client Graham Platner dropped out of the Senate race in Maine earlier this year amid scandal, Katz worked this cycle for Gina Hinojosa in Texas, Randy Villegas in California and Brian Poindexter in Ohio, while his firm, Fight Agency, worked with El-Sayed and Pennsylvania’s Bob Brooks.

The day before the election, The Atlantic published a 3,500-word piece that put “Katz’s theory of politics” on the ballot.

“A lot of people wanted to know what I’d say if we lost,” Katz said, referencing an infamous Kanye West quote Wednesday and running on 45 minutes of sleep. “I guess we’ll never know. That’s about how I feel today.”

Like Sanders, Katz sees a progressive future laser-focused on economics as the clear way forward — and nowhere is that more clear than in Texas.

“Hundreds of millions were spent against James and Gina trying to tag them on a trans issue,” he said. “It failed in epic fashion because there was no room for misunderstanding or ambiguity over what they stood for, because they had grounded themselves in such affirmative and positive economic messaging.”

“Those attacks have succeeded in the absence of an affirmative message,” he added. “Once you’re able to define yourself and provide a message, it's just a lot harder for that to work.”

It's the same formula Mamdani rode to Gracie Mansion — and, Katz argues, the lesson Democrats finally absorbed. “For a long time, politicians accepted the realities of how people felt about the economy but refused responsibility for having to take an active role in changing it,” he said. “There's no room for that anymore.”

Katz sees his and Sanders’ theory of politics as having won out across the Democratic spectrum — not just on the left flank, but among the moderates who once resisted it.

“The more moderate wing of the party has changed the definition of what a moderate is. I think that’s great,” he said. “We should be a big tent party, but you are seeing a big tent that is unified in opposition to the oligarchy, that is unified in opposition to corruption, and that is united in a pursuit of fundamental and structural change. And that’s going to be really encouraging if that can carry over to 2028.”

For Sanders, it’s vindication of an argument he's made for years and that Democrats have ignored — despite what he says is its simplicity.

“Focusing on the needs of the vast majority of American people who are struggling in the richest country on earth, while the very rich are getting richer, man, you don't need a Ph.D. in economics or political science to figure that out,” he said. “That is the issue. How do we create a decent standard of living for all of our people? How do we end the corrupt campaign finance system? That is exactly what Democrats have got to do.”

At 85, Sanders campaigned this cycle like a man running out of time.

In the wake of Trump’s historic return to power in 2024, Sanders launched the “Fighting Oligarchy” tour, which came when many democrats were on the sidelines but provided a lot of the arguments, and even helped discover actual candidates who a year later would swamp races earlier this week. Since the tour, Sanders has held 58 rallies during the midterms, endorsed more than 150 candidates across the primaries and general election, spent north of $16 million on organizing and deployed staff and volunteers into key Senate states including Michigan, Minnesota and Florida, an adviser to Sanders told POLITICO.

“People say, ‘you know, Bernie, you’re not 21 years of age. What keeps you going?’” Sanders said. “What keeps me going is you look at the people who we have just elected yesterday, and look at the hundreds of other people who we have elected in school board and city council. You have wonderful people, black and white and Latino, coming from rural areas, urban areas.”

“I hope the Democratic leadership has seen what's happening around the country,” he added.

Looking ahead to 2028, progressives see Tuesday as evidence the left’s economic politics can win anywhere — and that any doubt from moderates that a progressive should run for president should be laid to rest.

“I think we’ve got to rethink politics,” Sanders said. “We can win over millions of Republicans and independents who are struggling economically if we focus on the issues that are important,” he added, pointing to Villegas in Bakersfield, “a Republican town,” along with Forstag, Cooke and others who flipped Republican-held seats.

“These are people who ran on a progressive agenda, taking on a Republican district, and they won,” he said.

Katz said Tuesday was proof that heading into 2028, voters want candidates who look nothing like Washington — the kind he's helped elect from Texas to California.

“You saw a hunger for a different kind of candidate — on congressional [level], teachers and waitresses and firefighters and iron workers and smokejumpers. And on the Senate level, pastors and doctors and teachers,” he said. “This hunger for expanding who is in Congress, who's in the positions of power, feels real.”

What progressive candidate can pick up the left’s momentum heading into 2028 remains a question, but Katz said he viewed Tuesday’s results as more evidence that New York Rep. Alexandria Ocasio-Cortez — who closed out Villegas’ campaign in California a week before the election and stumped in Michigan, Montana and Pennsylvania — should consider running for president.

“You’d be hard pressed to look at the results of the election and say they're anything other than encouraging in the context of her ability to win nationwide,” Katz said.

Lisa Kashinsky contributed to this report.