Mayor Zohran Mamdani and his Democratic Socialists of America are now the most capable political force in the Democratic Party heading into 2028. In yesterday’s primaries in New York, his three endorsed candidates beat better-established adversaries, demonstrating how Mamdani and the DSA have become the face of the party’s progressive wing.
The mayor’s endorsements broke with—and even double-crossed—party leaders who supported his rapid rise in last year’s mayoral race. His move opened a significant rift with Hispanic leaders, organized labor, pro-Israel Democrats, and veteran incumbents that ordinarily form an essential part of any Democrat’s electoral coalition.
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But the gambit paid off—at least in the short run.
Start with the most important and closest race, NY-13. Last year, Mamdani pledged to endorse Adriano Espaillat, the establishment progressive Democrat who represents most of Harlem, Washington Heights, and a part of the Bronx. Backed by the city’s biggest labor unions, Espaillat is chairman of the Congressional Hispanic Caucus and has held elective office for nearly 30 years.
But Espaillat backed Andrew Cuomo in the mayoral primary before switching sides to support Mamdani in the general election. The congressman also generally supports Israel. In response, Mamdani broke his pledge and endorsed Espaillat’s rival, Darializa Avila Chevalier, a 32-year-old former organizer in his campaign who belongs to the DSA.
Radically anti-Israel, Chevalier attended a pro-Palestinian DSA rally the day after Hamas’s heinous October 7, 2023, massacre and hostage-taking of Israelis. She has a history of inflammatory social media posts, including many lambasting leading Democrats, one calling Joe Biden a “rapist,” and another maligning interracial relationships. On Tuesday morning, she walked off a Spanish-language radio interview after the hosts questioned her past posts referring to the Dominican flag as “violent.”
Chevalier’s win shows that even little-known, unhinged radicals can upend the lethargic Democratic establishment—so long as they have Mamdani’s approval to activate the DSA machine.
Mamdani’s endorsements also alienated three-decade incumbent Brooklyn congresswoman Nydia Velázquez. The first Puerto Rican woman elected to Congress, Velázquez took a risk to endorse Mamdani’s mayoral campaign before any other member of the city’s congressional delegation.
The progressive Velázquez decided to retire and chose as her successor Brooklyn Borough President Antonio Reynoso, a native of Williamsburg and a union-backed progressive who isn’t part of the DSA. Mamdani, however, endorsed Reynoso’s primary rival, DSA member Claire Valdez, a 36-year-old transplant from Texas to Ridgewood who has served only one full year in the state assembly.
Behind closed doors, Velázquez seethed at Mamdani’s betrayal. Some of her rage seeped into her public statements as well, as when she warned Mamdani that “honeymoons are short.” “I’m trying to be respectful,” she said.
Brad Lander, the former city comptroller, also defeated establishment incumbent congressman Dan Goldman in NY-10, spanning lower Manhattan and parts of Brooklyn. A mayoral hopeful himself, Lander allied with Mamdani during last year’s primary to ensure Andrew Cuomo’s demise. Mamdani denied Lander a job in his administration, instead offloading him as a primary challenger.
Perhaps more than any other race, the Lander–Goldman contest was defined by the candidates’ positions on Israel. On Sunday, a café in Williamsburg, Brooklyn posted on social media that it had refunded Goldman’s coffee and told him he wasn’t welcome because of his pro-Israel views. Mamdani stayed quiet about the incident. By assisting Lander, Mamdani again eliminated a pro-Israel voice from the city’s congressional delegation while simultaneously repaying Lander for his help in last year’s primary.
Yesterday’s turnout fell short of last year’s higher-than-average showing for the mayoral primary, allowing the DSA to wield disproportionate influence. NY-13, for example, has about 373,000 total registered Democrats. Preliminary estimates suggest that about 75,000 voters participated in yesterday’s primary, or 20 percent. That’s roughly in line with the 78,000 votes cast in the district’s 2020 primary.
Now that all three of Mamdani’s endorsees have won, he will continue his transformation of the DSA from a group of fringe agitators attached to the Democratic Party into a modern version of the Tammany Hall machine. Through on-the-ground canvassing, smart messaging, and social media, the DSA can secure victory for candidates willing to advance its policies, regardless of their backgrounds or extremism.
Yet the mayor’s gambit has placed him at odds with the pillars of the New York Democratic establishment. Governor Kathy Hochul, U.S. House Minority Leader Hakeem Jeffries, and the Congressional Black Caucus supported Espaillat’s reelection, for example.
Establishment Democrats have a few options to respond. They can emulate Cuomo’s general-election run last year and back Espaillat in a third-party bid. Unlike yesterday’s races, which were limited to registered Democrats, November’s contest will be open to all voters, and about a quarter of NY-13 voters are not registered Democrats. With his name recognition, support from labor unions and party leadership, higher turnout, and with figures like Velázquez seeking revenge, Espaillat might pull off a general-election upset in the heavily Democratic district.
In the long run, establishment Democrats could consider electoral reform to prevent the DSA takeover of their party. For decades, the city’s closed primaries entrenched the power of the Democratic establishment and special interests like labor unions. Now the DSA has mastered the ground game and turned closed primaries against labor and establishment candidates. Opening primaries to all registered voters, or even more sweeping changes like proportional representation, could expand the electorate and dilute the DSA’s advantage.
If establishment Democrats don’t adapt quickly, Mamdani won’t just defeat them in primaries. He’ll redefine the party on his terms.