It's the Friday after Valentine's Day The radical publishing house Verso Books is throwing its annual Red Party, an anti-romance-themed banger. Like a lot of the best lefty parties, it takes place in Verso's book-lined Jay Street loft, ten stories above cobble-stoned Dumbo. The view of the East River is splendid, the DJ is good, and the beers cost three bucks.

The roster tonight is heavy on extremely online political-media types. The podcaster and performer Katie Halper tells me she's a fourth-generation socialist from the Upper West Side who used to attend a summer camp once affiliated with a communist organization called the International Workers Order. The hosts of the leftist podcast Chapo Trap House are not here, but Eli Valley, the gonzo artist who illustrated their book, is, as is Dave Klion, a ubiquitous Twitter pundit recently seen feuding with CNN's Jake Tapper. Nearby, Sarah Leonard, who, at 30, is a veteran of the lefty-journalism orbit, tells me she's launching a Marxist-feminist glossy called Lux, named for Rosa Luxemburg.

The guests of honor tonight are the creators of Red Yenta, a new DIY dating platform: Marissa Brostoff, 33, a grad student at CUNY, and Mindy Isser, 28, an organizer in Philly. "I was complaining about how socialist men don't date socialist women and it really bothers me," Isser says. Online, there wasn't a good way to filter for someone's politics. Sample bio: "Labor activist and aspiring historian/sci-fi writer looking for friends/open relationships. Tell me about your student debt and let's together."

An hour into the party, Isser and Brostoff stage a version of The Dating Game-one bachelorette, four suitors-to promote Red Yenta. Friend-of-the-app Natasha Lennard, a columnist at the Intercept, yells for quiet. "There is a service--a communal service--that is better than a Tinder, or the last hurrahs of an OKCupid," she announces. Who wants to slog through a few bad dates only "to find out that someone is a liberal?" Brostoff takes the mic. Pins and posters are available for purchase, she says, and donations are of course welcome. "That's how we became capitalists," she jokes. "And that's what you call irony. Or dialectics."

The bachelorette, Arielle Cohen--30, former co-chair of the Pittsburgh chapter of Democratic Socialists of America (DSA)--asks her suitors a question. "Now that Amazon has been banished from New York"--triumphant shouting here--"you're the one who gets free rein to build something ungodly in Queens: What are you building?" Some answers ring out--guillotine, public housing--but the invocation of Amazon is all it takes to get the party going.

A day earlier, Amazon had stunned the city by scrapping plans to build a new headquarters in Queens. Polls said a majority of New Yorkers, including Queens residents, favored Amazon's arrival. As did the mayor, the governor, and the editorial pages of the New York Times and the Daily News. The grassroots opposition, which included DSA, had the backing of some new Democratic muscle in Albany and, crucially, the vocal support of socialist superhero Alexandria Ocasio-Cortez, whose district...