Democratic socialists won big in New York’s primaries Tuesday, as two members of the Democratic Socialists of America defeated the Democratic establishment choices in congressional primaries, and several more triumphed in state legislative primaries.

The victories suggested that DSA member Zohran Mamdani’s election as mayor of New York City last year wasn’t a fluke. Democratic socialism has become a real force to be reckoned with not just in New York — but in several cities around the country.

In Washington, DC, DSA member Janeese Lewis George won a blowout victory in Democrats’ mayoral primary last week, making her all but certain to be the district’s next mayor.

In Seattle, Mayor Katie Wilson, who defeated incumbent mayor Bruce Harrell last year, is a self-identified democratic socialist. And in Los Angeles, city council member Nithya Raman, a DSA member, advanced to this November’s runoff against Mayor Karen Bass.

The DSA has also elected several members of the city councils of New York, Los Angeles, Minneapolis, Chicago, Portland (Oregon), San Antonio, and more. And they’ve elected a handful of state legislators in many states — mostly from urban districts.

But winning beyond deep-blue urban areas — in suburbs, in rural areas, and in statewide contests — is a tougher challenge.

That’s even true in New York, where on Tuesday, establishment-backed Democrats turned back left challengers easily in the state comptroller race and in the state’s most competitive GOP-held House district. (The DSA did not endorse in either race — likely in part because they thought they had little chance of winning.) Mamdani’s favorability ratings statewide are not especially impressive either, considering New York is a blue state.

So what are the main reasons the DSA has been catching on in big cities — and what do those reasons tell us about whether it might eventually catch on elsewhere, too?

Cities have, of course, long voted overwhelmingly for Democrats. But the rise of the democratic socialists is a more recent phenomenon — occurring gradually over about the past decade, before its explosion last year.

In most cases, the takeover followed a pattern — there was an increasingly sclerotic Democratic establishment that had been in power for a while, and that had gotten out of touch with the concerns of its increasingly left-leaning base.

“The Democratic Party apparatus that has traditionally been responsible for providing goods and services and representation to the people has atrophied,” said Asad Dandia, a public historian from Brooklyn.

As the party machines looked increasingly hollow, the DSA tried to fill the gap with organizing — something they were particularly successful at in New York.

“The NYC DSA is the crown jewel of all the DSA networks around the country,” pollster Adam Carlson told me. “My understanding is a lot of it’s just like hustle — they’re out in the community, they’re talking to people. One of the reasons why they’re so successful in cities is literally that they’re walkable.”

This led to some DSA successes in the late 2010s, such as the election of Rep. Alexandria Ocasio-Cortez (D-NY) to Congress. But the Biden administration years brought some stasis for the party.

Then, over the past few years, a confluence of political changes revived their prospects — by discrediting the Democratic establishment in the eyes of many of its voters. The Israel-Gaza war became a moral litmus test to many on the left. And the failure of the party establishment to stop Trump from returning to power — followed by his immigration crackdown and other crises — spurred an appetite for change.

All this occurred amid the simmering issue of affordability and the cost of living in the post-Covid economy — something that millennials and zoomers living in expensive cities felt acutely. And many came to view the party establishment as representing the status quo.

“DSA largely comprises young people — people in their 20s and 30s — who are for the most part college-educated and renters,” said Dandia. “I’m including myself in this category. We don’t have access to the resources and the wealth and the necessities for us to achieve the American dream. We get stuck with being perennial renters. We’d like to advance in life, just like everyone else has, and we haven’t had the opportunity to do so because of these gaping inequalities.”

So in several cities now, democratic socialists have put up younger, progressive “change” candidates who’ve channeled many voters’ dissatisfaction with the Democratic establishments both in their cities and nationally – and promised something new, while an increasingly out-of-touch establishment was defending the past.

“You have an extremely energized left activist network that really knows how to put together a ground game, whereas on the moderate side there’s just a void,” said Jordan Weissmann of the Progressive Policy Institute (who is sympathetic to the moderates). “What’s the center-left organization that is supposed to provide any kind of counterweight to DSA? There’s none.”

Democratic socialists have won big-city mayoralties and parts of city councils, and they’ll have several members of Congress. But winning elsewhere will be more of a challenge.

“Predictably, our electoral victories map pretty closely onto blue cities and blue states, that’s not surprising,” DSA national co-chair Megan Romer told me. “We’re not blind to this. It is something that is being worked on.”

Suburbs and rural areas are simply less Democratic than cities, but even the Democrats there are older and typically less left-leaning, and different issues are salient to them — for instance, they are more likely to own homes. “Homeowners don’t want to rock the boat as much,” said Carlson.

“We talk a lot about housing justice and housing policy, and that is mostly relevant to people who live in places with apartments and lots of landlords,” Romer said. “We have to figure out, okay, what policies do we have that can work out here?” She flagged opposition to data centers as one possibility.

Carlson also cited the logistical difficulties of organizing outside cities, in areas where populations are less dense and concentrated: “I’m not going to say it’s impossible. But as it stands right now, without some kind of national unifying force behind it, like a presidential campaign, or maybe a really compelling statewide campaign — it’s tough to see.”

Even in cities, there’s a big question about how the socialists will fare in the longer term, as they move from the opposition faction to the governing faction. Can they actually address the cost of living crisis and prove they can run the snowplows the next time a blizzard rolls through?

Mamdani is well aware the stakes for the broader leftist movement rest in how well his city functions now that it’s in the spotlight. He identifies as a “sewer socialist” — a term for early-20th-century elected socialists who emphasized their competence in providing basic services like sanitation and health care over grander ideological struggles. And he’s been notably pragmatic in his own governance, including keeping his predecessor’s police chief.

So far, it’s working, but there are recent examples of local governments electing ambitious progressives and failing to deliver. Weissmann pointed to San Francisco, which had a very left-leaning government for years, as one example where “moderates really took time to organize and build a coherent vision to respond to the city’s problems” — and then regained power. Mayor Daniel Lurie has maintained his popularity since winning in 2024 — his approval was in the 70s in one poll this year — while emphasizing public safety and new housing affordability plans.

It’s one thing to be the “change” faction capitalizing on voters’ unhappiness with the establishment. It’s quite another challenge to keep those voters happy, and actually solve their problems, once you are the establishment. If socialists hope to succeed outside of cities, the first step is probably to prove they can actually govern cities well.