The gradations of Democratic blue are on display in New York’s congressional primaries this Tuesday, where high-profile races are already highlighting the party’s emerging divisions over how to regulate artificial intelligence, immigration enforcement, and the United States’ relationship with Israel.

The primaries are also an important test of political strength for New York City Mayor Zohran Mamdani and the emerging socialist left. Mamdani has thrown his weight behind three congressional candidates in particular: former New York City comptroller Brad Lander and two democratic socialists, Claire Valdez and Darializa Avila Chevalier.

Lander, Mamdani’s (amicable) onetime rival in last year’s mayoral race, is challenging incumbent Democratic Rep. Dan Goldman from the left in New York’s 10th District, while Valdez is running for an open seat in New York’s 7th District. Avila Chevalier, like Goldman, is hoping to unseat an incumbent Democrat, Rep. Adriano Espaillat, in New York’s 13th.

Some of Mamdani’s onetime allies, however, have ended up on the wrong side of his play to cement his influence over Democratic politics in New York City. Espaillat, a five-term incumbent and chair of the Congressional Hispanic Caucus, endorsed Mamdani ahead of last year’s mayoral general election (he had backed Mamdani’s rival Andrew Cuomo in the primary). And Antonio Reynoso, the Brooklyn borough president running against Valdez in New York’s 7th, was an early Mamdani supporter.

Reynoso is a particularly noteworthy case. He was hand-chosen by retiring Rep. Nydia Velázquez, a key Mamdani endorser who has represented New York’s 7th District since 2013. But Reynoso and Velázquez are Working Families Party Democrats, not democratic socialist Democrats, and that distinction increasingly matters in Mamdani’s New York City. (The WFP, while progressive, is more akin to Sen. Elizabeth Warren’s wing of the Democratic Party — its national leadership endorsed her 2020 presidential campaign — while DSA is in many ways the child of Sen. Bernie Sanders.)

Mamdani, and the left he comes from, now see an opportunity to make their mark in some of the country’s bluest districts — and gain a foothold in the Democratic Party in the process. But as the race for New York’s 7th District proves, it won’t all be smooth sailing.

This weekend, I talked to Reynoso and Velázquez about what’s at stake in these primaries – and the distinction between a progressive and a democratic socialist. I also asked whether they feel that Mamdani betrayed their early support by backing another candidate. Our conversation has been edited for length and clarity.

The mayor endorsed Claire Valdez over you, even though you were an early supporter of his. Where does the DSA’s politics actually diverge from yours?

Reynoso: The gap is coalition. We learned very young in the progressive movement — the first question they ever ask of you is, can you build coalitions? That’s always been a tenet of who we are. The DSA is a part of the progressive movement, but it isn’t the only progressive movement. The movement includes tenant association presidents, all of whom have endorsed me. It includes unions, of which I have the most. The first person to endorse Zohran Mamdani was Alexandria Ocasio-Cortez, and I have her endorsement.

The Working Families Party laid down the groundwork 20 years ago for the success of a mayor like Mamdani. Letitia James has been the face of the fight against Donald Trump. Make the Road New York, Churches United for Housing, New York Communities for Change — all of it is part of the movement, and the movement is broad and expansive. That coalition helped get Mamdani elected, and it’s the coalition carrying me right now. They are a member of the movement, but they are not the entire movement.

Congresswoman, you were one of Mamdani’s earliest and most important endorsers, but he hasn’t returned the favor here. Is “betrayal” too strong a word?

Velázquez: I have respect for Mayor Mamdani. His victory was historic. And to the point Antonio just made, DSA didn’t win that election — a coalition did, and I was part of that coalition. In terms of the mayor and even DSA, we agree on most of what matters. We make different choices in this race, but you know what, that’s the nature of politics.

Endorsements are one of the few things a member of Congress does as an individual. I made mine based on knowing this district and knowing Antonio Reynoso for decades. I want Zohran to succeed, because he’s talking to the issues people care about — affordability, access to quality health care, protecting the most vulnerable. On those points, I support him. On electing the most experienced, qualified, tested candidate, that’s Antonio.

You’ve spent a big chunk of your final stretch in Congress on this race. Why was it so important to you?

Velázquez: Because this is a person who was born here. He is a son of this community. I was a teacher, I was a professor, and I always told my students: If you work hard and play by the rules, you can make it. That is exactly what Antonio has done with his life. And it’s important to know he is not an establishment candidate. He has spent his entire career taking on the machine.

When I was fighting corruption and party bosses in Brooklyn, Antonio was there fighting with me. He co-founded New Kings Democrats to challenge the party bosses, and he took down Vito Lopez, one of the most powerful machine bosses this borough has ever seen. Isn’t that what we need at this moment — a fighter who will not be intimidated by the powers that be?

The DSA has tried to cast you as the establishment candidate, and in some ways, the focus on ideology seems to make “experience” feel like a liability. What would it say if voters look past it?

Reynoso: Let’s wait until [June 23] and see. In my entire political career, experience has never been a negative thing. People are trying to make ugly of things that are deeply important to what leadership means. Bernie Sanders has more seniority than almost any senator in the country, and he’s still beloved — he’s not faulted for his years in office.

There’s something different between time and work. You can be somewhere for a long time and do absolutely nothing, but my time has always been focused on results. I passed arguably one of the greatest legislative records in my eight years on the City Council — I’d challenge any member to stack their record against mine. I don’t want to be elected just because I’ve been in politics longer. I want the votes because the work I did was valuable.

What’s the biggest distinction between you and your opponent?

Reynoso: We’re at a time when the federal government seems to be handing down crisis after crisis after crisis. Every day we wake up, and there’s an unnecessary or illegal war, there’s cuts to [Supplemental Nutrition Assistance Program] benefits, there’s cuts to Medicaid. What we need is a fighter who can actually solve the problems people in this district have.

My history of fighting ICE and Rikers Island, helping migrants get work authorization, my work on Black maternal health, my tenant safety legislation — that record means something here. And my conviction doesn’t come from reading stories in a book or seeing pain on TV. I’m a poor kid from the south side of Williamsburg. I was raised on food stamps and Section 8 and every government subsidy you could imagine. It’s my lived experience. That’s my north star.