It’s not unusual to hear chants of “U-S-A” at a political event. But the chant that rang repeatedly around Williamsburg’s 99 Scott Studio after last night’s near-total sweep by socialist candidates was off by one letter: “D-S-A.”

The acronym refers to the Democratic Socialists of America, whose New York chapter, NYC-DSA, emerged as the major winner in last night’s primary elections in New York: all but one of its ten-person slate of insurgent candidates won their races for US Congress and New York’s state legislature. They did so on the back of a furious, sweat-drenched door-knocking operation that has, a year after a similar grassroots effort catapulted another member, Zohran Mamdani, into the New York mayor’s office, firmly established the group as a formidable political force — one that bested unions and even the Working Families Party (WFP), for decades the leading progressive electoral power in the city.

Even in their disbelief at how quickly and decisively the results had gone their way, the hundreds of rapturous DSA members who packed into the now–Democratic nominee for New York’s Seventh Congressional District Claire Valdez’s official watch party were keenly aware of their newfound power.

“You’re next! You’re next!” they chanted as House Minority Leader Hakeem Jeffries, a longtime foe of the Left, appeared on the screen. One winning candidate after another came up to implore those listening to join the organization.

“The water is warm — join us,” Diana Moreno, who had won a special election to replace Mamdani in the New York State Assembly earlier this year, told the crowd. “Join this beautiful movement.”

That included Valdez, a union organizer and barely first-term state assemblywoman who won a major upset with her 21 point victory over the WFP-backed Brooklyn borough president, Antonio Reynoso, for the House seat held for sixteen terms by longtime progressive stalwart Nydia Velázquez.

Even for a congressional campaign involving a socialist insurgent, Valdez’s race took on unusually high stakes.

One reason was the WFP’s involvement, turning the contest into something of a progressive turf war. The WFP’s New York director told the New York Times they had advised Reynoso that he “can’t cede the left lane to Claire [Valdez] and the DSA.” Reynoso himself framed the race as “the DSA and Zohran Mamdani and Bernie Sanders versus the WFP, and [attorney general] Tish James, [public advocate] Jumaane Williams, the group of progressives that have been doing a lot of work for a long time.”

The other reason was Mamdani himself. Rather than choosing a DSA candidate approved of and mentored by Velázquez, of whom there were several, Mamdani opted to back someone he considered a closer ally in Valdez, triggering an unusually bitter and public falling out with the outgoing congresswoman, who had been one of his earliest backers when he launched his longshot mayoral bid. The move was a risk: a loss would have, perhaps fatally, diminished both himself and the movement behind him barely half a year into his term.

After alarm at a collapse in turnout prompted an emergency DSA meeting, the organization kicked into high gear, with many members canvassing incessantly. The weekend before the vote saw a surge of door-knockers, some doing back-to-back three-hour shifts.

Coming on the back of months of patient door-knocking, the last-minute burst of pavement-pounding seemed to have done the trick. Several canvassers said their concerns about Election Day, poll numbers, and the predictions made by pundits withered in the face of their interactions with real voters in the progressive, pro-Mamdani districts they campaigned in, who again and again told DSA door-knockers they intended to vote for the socialist candidates over their opponents.

Beyond the candidates, both DSA and socialism itself appear to have gone mainstream with last night’s result. Only a few years after DSA candidates were occasionally de-emphasizing their democratic socialism to try and win over ordinary voters, canvassers this time found the label an asset.

The voter response to DSA was “unprecedentedly positive,” said DSA member Max Fisher, thirty-four. One voter, a middle-aged South Asian woman, professed she was voting not for any particular candidate but for DSA itself. “I’m voting up and down party line,” was the way another voter described voting for the DSA slate. At a time when both established parties and most politicians are widely viewed as corrupt and dishonest, voters at the doors appeared to value candidates who identified as democratic socialists, reported Simon, thirty-six, another DSA canvasser.

It’s a development that likely couldn’t have happened without the Democratic Party’s collapse in standing among its own voters over the past year and a half. In fact, beyond the socialist slate, last night saw at least a dozen Democratic incumbents trail more progressive challengers, including former New York City Comptroller and Mamdani endorsee Brad Lander, who trounced two-term Rep. Dan Goldman, hammering him for not going far enough to criticize Israel’s genocide or restrict arms sales in response to it.

Last night’s elections, then, are of a piece with the trend seen across the country, whether in Maine Democratic voters’ overwhelming rejection of their centrist governor for a scandal-plagued political novice, Graham Platner way to her left, or Mamdani’s own victory over onetime Democratic Party princeling Andrew Cuomo. With the Democratic brand in the gutter thanks to what is widely viewed as the party establishment’s feckless and inept opposition to Donald Trump, the door has been blown wide open for the left-wing insurgents who have previously had to fend off, and even fell to, charges of party disloyalty or not being “real” Democrats. Just look at Congresswoman-elect Darializa Avila Chevalier, who weathered what were meant to be damaging revelations that she had, among other things, called Joe Biden a “war criminal” and once tweeted “F-ck Kamala Harris.”

They’re also of a piece with a different trend. As Chevalier and Lander’s victories point to, besides a win for DSA and the socialist left, last night’s result was a major defeat for the pro-Israel lobby, which had once more spent big on defeating socialist candidates critical of Israel and its genocide of Palestinians. Coming a year after Mamdani’s own win over Cuomo’s obsessively pro-Israel campaign, the result solidifies the fact that unconditional support for Israel — as it meddles in US politics and rampages across the Middle East — is no longer good politics nor good policy, even in New York, once the beating heart of American Zionism.