NEW YORK — New York City Mayor Zohran Mamdani’s pick to succeed him in the state Assembly cruised to an easy victory Tuesday night. But Diana Moreno’s win in that Queens special election is likely the last cakewalk we’ll see from a Mamdani-backed candidate in the near future.

The new mayor has endorsed Brad Lander in his quest to unseat Rep. Dan Goldman in New York’s 10th Congressional District and Assemblymember Claire Valdez for the NY-07 seat being vacated by Rep. Nydia Velázquez.

The pair of Democratic congressional primaries is expected to be far more competitive than Moreno’s race, raising a central question: How far can a Mamdani endorsement get you?

“We’re testing that out,” said Grace Mausser, co-chair of the Democratic Socialists of America’s New York City chapter, which has endorsed both Moreno and Valdez, but not Lander. “He has a lot of hard resources that come with an endorsement: his impressive volunteer and donor lists, his strong reach on social media … There’s also the soft power that we’re testing out now, right? Who is the leader of left and progressive politics in New York right now?”

Mamdani has so far been more involved in boosting Valdez than Lander.

The mayor appeared with Valdez — a Queens lawmaker, former United Auto Workers union organizer and the first elected official to stand with Mamdani in his campaign for mayor — at an event the day after she launched her bid. He also filmed a whimsical social media video set in a subway station to boost her fundraising.

Valdez is running against Antonio Reynoso, the Brooklyn borough president who Velázquez has endorsed as her preferred successor. Queens City Council Member Julie Won also recently entered the race in the progressive Brooklyn and Queens district.

The mayor has been largely hands-off in Lander’s campaign after endorsing the former city comptroller on the day of his launch for Congress. Lander, who cross-endorsed Mamdani in last year’s mayoral race, is running in Brooklyn and Manhattan against an incumbent with more than three times as much campaign cash on hand and the backing of Democratic House leadership, including Minority Leader Hakeem Jeffries.

A political adviser to Mamdani said his team is still assessing how much to get involved in the two congressional contests and cautioned against reading anything into the fact that the mayor has been more involved in Valdez’s race so far. The adviser said the Mamdani team is waiting to make major moves in NY-10 pending the outcome of a court case that could scramble the lines of the district in such a way that Goldman may run in the neighboring 11th District instead.

Regardless, the Mamdani adviser, who was granted anonymity to discuss internal strategy, said the mayor simply lending his name to Lander and Valdez “already carries a lot of weight that these campaigns can make the most of.”

“His direct involvement is always going to be second to governing,” said the aide. “Ninety-nine percent of his energy is going to be focused on running the city.”

The politics-versus-governance balance is part of Mamdani’s clash with Velázquez, the highly respected progressive who effectively warned him in a New York Times interview to stay in his lane.

And the mayor does have a lot of work to do at the helm of the country’s largest city. June’s congressional primaries fall around the same time he and the City Council will be putting finishing touches on the city budget amid serious fiscal headwinds.

“I don’t know if that was the wisest thing for him to do because the job of being mayor is so big,” Democratic strategist Lupe Todd-Medina said, arguing Mamdani could end up in a situation where he’s not able to stump for Lander and Valdez as much as they want and need him to due to the sheer burden of governing New York City.

As June’s primaries still loom more than four months away, a Lander campaign official, granted anonymity to share sensitive considerations, said his team is also still waiting to see if a court decision could rip up the lines of NY-10.

But if the race ends up competitive, the Lander aide said his team is confident Mamdani will help fundraise and campaign for the former comptroller. The fact that Mamdani hasn’t done so yet, the aide said, is understandable since the mayor has been focused on governing in his first month in office.

The two House primaries have different dynamics but they’ll determine whether Mamdani can replicate the magic that catapulted him from relative obscurity to the nation’s second toughest job.

“He has a lot at stake by pushing in some chips on two fronts, but I think he has more at stake in the 7th District,” said Michael Lange, an analyst who specializes in progressive politics. Valdez “is a really close ally who comes from his political movement and his political home.”