There’s a seeming paradox at the epicenter of the political earthquake that hit New York City on Tuesday night, when a trio of Democratic Socialists of America (DSA) and Zohran Mamdani–backed candidates triumphed in congressional primaries across the city. The progressive candidates who claim to represent a working-class revolution won thanks to the votes of the well-educated, credentialed, and affluent, while low-income New Yorkers tended to back the more moderate candidate. The results reflect a nationwide political reality: Across the country, higher education and income increasingly correlate with progressive voting, while working-class voters—including in long-established immigrant communities—opt for more moderate...