Mamdani Effect: NYC Progressives Warn Incumbents Their Seats Are Vulnerable

A political earthquake is rumbling beneath the bedrock of New York City's Democratic establishment. The tremor's source? Mayor-elect Zohran Mamdani's stunning victory. His success has not just put the spotlight on progressive politics, it has fundamentally re-energised the left, prompting a wave of ambitious challengers to set their sights on some of the most powerful House seats in the city, and perhaps in the nation.

For too long, the idea of unseating entrenched Democratic heavyweights seemed like a political fantasy. Yet, Mamdani's 2025 win—coming after he was 'famously polling at 1 per cent' before surging — has injected a potent dose of reality and hope into the progressive movement. The momentum is undeniable. New York City Councilmembers Chi Ossé and Alexa Avilés are reportedly weighing bids to oust House Minority Leader Hakeem Jeffries and Rep. Dan Goldman, respectively.

Both have sought the crucial endorsement of the city's Democratic Socialists of America (DSA) chapter to fuel their campaigns. Meanwhile, left-wing challengers have already emerged against Reps. Ritchie Torres, Adriano Espaillat and Grace Meng. While some experts are quick to label these campaigns as 'long shots,' organisers on the ground believe Mamdani's improbable trajectory provides a blueprint for victory.

Andre Easton, a Party of Socialism and Liberation member who launched a campaign against Torres, captured the mood perfectly: 'Mamdani's win absolutely has energized and put a set of excitement for not only socialists and left-leaning people or progressives, but anybody that is desirous of a change.'

The Mamdani Momentum: Concrete Data Fuelling Progressive Challenges

The concrete numbers behind the Mamdani win are what's truly electrifying the progressive base. His November general election saw the city's highest voter turnout in almost a century. Even more tellingly, Mamdani managed to outperform former New York Governor Andrew Cuomo, who ran as an Independent, in nine of 13 congressional districts, including those held by the powerful Jeffries and Torres. Sebastian Leon Martinez, coordinator of the Democratic Socialists of America's (DSA) New York City chapter's youth branch, observed, 'We're seeing that Zohran really picked up a lot of areas that many would say underperformed in the primaries.'

This success stems, in part, from the highly effective, aggressive on-the-ground campaigns led by the DSA. They were also instrumental in Rep. Alexandria Ocasio-Cortez's 2018 upset against moderate Democratic incumbent Rep. Joe Crowley. Building on this, the Justice Democrats, another organisation key to Ocasio-Cortez's win, recently endorsed Harlem-based organiser Darializa Avila Chevalier, who is primarying Espaillat.

Avila Chevalier, a former Columbia student, told The New York Times earlier this week that 'I think that Zohran's win convinced so many on the left that this is possible' and stressed the need to 'build on that momentum'. Rep. Grace Meng (D) has also drawn a challenge from the left in Chuck Park, a former foreign service worker. He has attacked Meng for accepting corporate donations and being out of touch on affordability, the central theme of Mamdani's campaign.

Further bolstering the movement's strength, Grace Mausser, one of the New York City DSA's co-chairs, revealed that the organisation's membership has doubled in the past year to over 12,000 people. This massive ground force enables them to potentially support an unprecedented number of campaigns in the 2026 election cycle.

'Now that we have a citywide elected official who is coming into office with a very strong mandate, we think we have the opportunity to elect quite a few people who are aligned,' Mausser stated. And even if they don't win, she added, they can 'leverage Zohran's electoral success to pressure electeds to align with some of the policy ideas that he needs to implement his agenda.'

A Strategic Path Forward and the Incumbent Defence

Despite the progressive zeal, the path forward is complex. Interestingly, opposition to primarying sitting officials has come from Mamdani himself. He reportedly discouraged the DSA from endorsing Ossé's bid against Jeffries, saying it would be detrimental to implementing his affordability agenda.

The DSA ultimately voted against endorsing Ossé, leaving the fate of that campaign uncertain. Mamdani also reportedly said he would endorse city comptroller and former mayoral candidate Brand Lander in a race for Goldman's seat, which both experts and organisers believe is particularly vulnerable, given that Goldman won his initial election to Congress with less than half his district's vote.

Political consultant Lupe Todd-Medina, president of Effective Media Strategies, cautioned against drawing simple parallels, saying, 'The comparison to what happened over the course of this past year with the election of Mamdani to mayor, is going to be very different than these races.' She argued that, with the exception of Goldman, incumbent Democrats in New York City are generally quite popular. Todd-Medina also called Mamdani's lack of endorsements in the congressional challenges 'smart' as he 'has to put together an administration'.

Veteran campaign strategist Jack O'Donnell noted that while 'folks in activist and more progressive communities [are] pushing back' is not unusual, Jeffries and Torres appear to enjoy strong support. However, the announced retirements of longtime congressmembers Jerry Nadler and Nydia Velázquez are poised to create significant political turbulence and opportunities. Both cited the need for generational change, and Nadler's seat has already drawn nine challengers, with Velázquez's seat likely to inspire similar competition.

Justin Chae, CEO of Supernova: Creative & Crisis, confirmed, 'There are certainly some open seats in New York that are drawing a lot of candidates and attention right now.'

Even if the socialist and progressive candidates do not all replicate Mamdani's success, the pipeline of future challengers is expanding rapidly. Martinez noted that the NYC-DSA's youth arm has inspired more colleges, including Columbia University, to create their own YDSA chapters. He concluded, 'You're going to see a lot of these young organisers who were activated by the Zohran campaign moving on to other races, whether they're local, state, or federal, and I know that they're going to play a crucial role in building up true working-class power.'

Given all these, the progressive fire has been lit, and its reach appears to extend far beyond the city hall.