Too extreme. Too inexperienced. An absolute disaster.

Mainstream politicians are sharpening their attacks, and the wealthy are threatening to move away as a socialist revolution sweeps through the city.

They’re not talking about Zohran Mamdani or his plans for New York City.

Rather, they are agonizing over the scene in Portland, Ore., where the democratic socialist principles espoused by Mr. Mamdani — the front-runner to become New York’s next mayor — have already taken root at City Hall.

Four members of the Democratic Socialists of America, along with their left-wing allies, have occasionally formed a working majority on Portland’s 12-person City Council this year, promising sweeping changes aimed at improving the lives of everyday residents. The socialists advocate raising taxes on the rich, enacting a widespread government-owned housing plan and opening city-run grocery stores — an idea Mr. Mamdani has also endorsed.

The establishment backlash to their tenure echoes the opposition Mr. Mamdani has faced in New York since winning the Democratic primary. Gov. Tina Kotek of Oregon, a Democrat, has criticized Portland’s high taxes and a costly universal preschool program the socialists cherish. Portland’s business community is warning that a war on capitalism and an exodus of job creators could send the city spiraling.

“If you start trying to create a socialist utopia in Portland, Oregon, I don’t see how you can avoid the fact that people with money are not going to be attracted to it,” said Frank Dixon, the former chair of the Oregon Democratic Party. “Isn’t that common sense?”

Still, for all the outrage, the first nine months in office for the Portland socialists — some of whom speak glowingly of Mr. Mamdani and display posters with his face and the phrase “Hot Commie Summer” at their offices — offer a cautionary tale about political outsiders’ abilities to upend the status quo.

The socialists have been limited by the same barriers that snarl more traditional politicians: a finite budget, the votes needed to pass legislation and an occasionally dysfunctional government. Although moderates are spooked by their talk of higher taxes and social housing — government-owned units not subject to fluctuations in rental prices — the socialists have not yet tried to muscle through such policies.

The socialists themselves say they have big goals but are trying to be responsible leaders, studying the impact of policies before working to enact them. They argue that the dire rhetoric about them reflects the anxieties of an out-of-touch establishment, refusing to cede power to a younger generation focused on the working class.

“Portland is a progressive city, but it hasn’t had progressive politics in a meaningful sense,” said Mitch Green, one of the socialist councilors. “This city has generally always been run by the rich, for the rich.”

Mr. Green traveled to Vienna last month to study that city’s government-owned housing program — a taxpayer-funded trip skewered by critics. (He plans to propose a similar program for Portland next May.)

He said he and his allies had been “hammered” by business interests urging them to lower taxes and cut regulations, so watching Mr. Mamdani rise “as an unabashed, pro-working class hero” was inspiring.

“It’s a reminder that I got elected because I talked about those same things,” he said. “We’re building a movement, from coast to coast.”

Portland’s Peacocks

The socialists’ emergence traces back to 2022, when voters approved changes to Portland’s century-old form of governance. They expanded the City Council to 12 members, from five, and adopted ranked-choice voting.

Nearly 100 candidates ran for the new City Council last year, and a handful earned the backing of Portland’s D.S.A., which plays an outsize role in a city where Republicans are an endangered species. Three D.S.A. members — Mr. Green, Sameer Kanal and Tiffany Koyama Lane — were elected. Another new councilor, Angelita Morillo, joined the D.S.A. in March.

The extent to which the four socialists and two other left-wing councilors were working together became clear in May, when they won a contentious vote to reallocate $2 million from the city’s proposed police department budget to parks maintenance. It was a provocative move at a time when many Democrats have backed away from calls to defund the police.

The hand-wringing over the socialists’ cohesion escalated in August, when Willamette Week, a local newspaper, reported on a group text in which the six progressives, referring to themselves as “Peacock” — shorthand for “progressive caucus” — closely coordinated their votes and occasionally mocked their more moderate colleagues.

Those six occasionally pick up support from a seventh councilor, giving them a majority on some legislation.

Rather than making its mark with a flurry of left-wing legislation, however, much of the council’s tenure has been defined by gridlock and infighting as it works out the basics of a new government on the fly.

That was on display last month, when Mr. Kanal and Eric Zimmerman, a moderate, traded barbs from the dais over a mundane procedural issue.

Olivia Clark, another moderate, chimed in. “What this conversation says to me,” she said, “is that we really need some marriage counseling.”

Some have tried. Two consulting firms offered to help mediate disputes, but some councilors balked. Dan Ryan, one of the moderates, said he was pushing for a more drastic step: a three-month pause on meetings so councilors could work out disagreements.

Trump Weighs In

In the 2010s, millennials flocked to Portland, and the city’s restaurants and quirky cultural scene attracted national headlines.

But in recent years, the city became known for boarded-up storefronts, open-air drug use, homeless encampments and explosive protests. Portland’s real estate market ranked 80th out of 81 cities in a national survey last year, ahead of only Hartford, Conn., underscoring a slow pandemic recovery. Oregon decriminalized all drugs in 2020, then reversed course last year after a surge in overdose deaths. Portland’s new mayor, Keith Wilson, has escalated sweeps on homeless encampments.

Last week, President Trump said he was authorizing the deployment of the National Guard to protect Portland, which he described as “war-ravaged,” as a small group of protesters camped outside an immigration enforcement facility have occasionally clashed with law enforcement. City and state leaders sued to block him.

Despite Mr. Trump’s rhetoric, violent crime has declined, and many of Portland’s leafy neighborhoods remain as appealing as ever. Still, the downtown was nearly empty on a recent muggy afternoon, and tents dotted the sidewalks.

How to respond to the problems here is at the heart of the divide between the socialists and the moderates.

Councilors like Ms. Clark and Mr. Ryan say they are plenty progressive themselves — simply more moderate by Portland’s standards — but residents want leaders focused on public safety, not expansive programs. The socialists counter that wealth disparity and an affordability crisis are at the root of Portland’s problems — a debate also reminiscent of New York’s mayoral race.

One of moderates’ biggest gripes is over taxes. The socialists have mulled higher taxes on the rich, but some residents and business owners say they already endure some of the highest taxes in the country without seeing improvements in basic city services.

“Why are you chasing the shiny objects when you really should be taking care of your fire stations, your parks, your streets?” Ms. Clark said. “Things are really deteriorating.”

They argue that high taxes are pushing wealthy residents away. Though not definitive, some data supports that premise: Fewer top filers contributed to the preschool tax in 2023 than in 2021, the county found. And federal migration data analyzed by the local research firm ECOnorthwest showed that the average income of those leaving the area has been outpacing those arriving.

The issue remains hotly debated, and Mr. Green’s office has published studies arguing that the claims are overhyped.

The moderate voices seem to have an ally in the governor’s mansion. A task force advising Ms. Kotek has urged the Portland region to lower taxes, and the governor has exhorted the county to “ease the current tax burden” imposed by the universal preschool program that local voters passed in 2020 — a request that Portland’s D.S.A. said was tantamount to “declaring war on preschool.”

At a downtown art gala last month, affinity for Portland’s socialists among champagne-sipping attendees was in short supply. The event celebrated the opening of a museum exhibit showcasing the collection of Jordan Schnitzer, a local billionaire and philanthropist.

Echoing concerns over Mr. Mamdani’s proposed tax on millionaires in New York, Mr. Schnitzer said many of his wealthy friends had left Portland in recent years, which he feared was harming the local economy.

Portland’s socialists “think business is a dirty word,” Mr. Schnitzer said.

But the socialists say Portland’s existential problems call for ambitious solutions, and the pushback comes from conservatives intent on maintaining the status quo.

“If the Democrats had been delivering materially and emotionally for the public, there would not be a need for socialists in office,” said Ms. Morillo, who was homeless for a time in college. “We would not see Zohran Mamdani succeed in New York.”

In a city considered one of the most progressive in the country, the debate over just how far-left to be has amused some longtime residents.

“In Portland, our political spectrum is not Republican to Democrat,” said Amy Ruiz, a local political consultant and lobbyist. “It’s, ‘Which shade of blue are you?’”