In the context of the 2025 New York City mayoral race, there wasn't a single "main" DSA member who led a campaign against Zohran Mamdani. In fact, Mamdani's candidacy was a massive point of pride for the NYC-DSA, which provided the "kitchen cabinet" and the ground game that powered his upset primary victory over Andrew Cuomo.
However, the DSA is famously a "big tent" of internal caucuses that often disagree on strategy. If you're looking for internal friction or high-profile socialist dissent, here are the key figures and groups that voiced opposition or concern at different stages:
While the Socialist Majority Caucus (SMC) (the largest in NYC-DSA) was all-in on Mamdani, other caucuses expressed reservations:
Marxist Unity Group (MUG): This caucus generally pushes for the DSA to act as an independent party rather than a wing of the Democrats. Some members were skeptical of Mamdani's decision to run as a Democrat and his willingness to collaborate with the party establishment once in office.
Emerge (The Communist Caucus): While many members canvassed for him, Emerge later led a push for Mamdani to fire his appointed NYPD Commissioner, Jessica Tisch, arguing that a socialist mayor should not retain a police commissioner focused on traditional enforcement.
Tensions flared after the mayoral election (late 2025) regarding City Council Member Chi Ossé.
Zohran Mamdani actually took the "moderate" socialist stance here, arguing against the DSA endorsing Ossé’s primary challenge to Hakeem Jeffries.
In contrast, Assembly Member Emily Gallagher (a fellow DSA-backed official) spoke in support of endorsing Ossé, creating a visible rift between Mamdani and the more "insurgent" wing of the DSA-elected officials.
Outside of the formal DSA endorsement process, other progressive figures with socialist ties expressed frustration:
Jessica Ramos: While not a "DSA member" in the formal sense (though often aligned with their issues), State Senator Ramos was notably critical of the "vibe-based" nature of Mamdani’s campaign, famously remarking that his success suggested you didn't need legislative experience to be mayor, "you just need to make good videos."
Brian Romero: A DSA member who ran for Mamdani's vacant Assembly seat, he found himself at odds with the "official" DSA candidate, Aber Kawas, and the mayor himself, who backed Diana Moreno.
In short: There wasn't one specific person trying to block him, but rather a debate between those who wanted him to be a "tribune of the people" (more radical/independent) and those who supported his "mass-politics" approach (winning the Democratic primary and governing through coalition).
Would you like me to look into the specific policy platforms that caused the most friction between Mamdani and the DSA’s more radical wing?