NEW YORK — Morris Katz, a top adviser to New York City Mayor Zohran Mamdani, quietly traveled to the United Kingdom last month to meet with local progressive politicians hoping to learn tools of the trade from the young strategist.

Katz’s trip coincided with the rise of a new left-wing challenge to the embattled Labour government from the Green Party, which snatched away a Manchester-area parliamentary seat in a February special election.

One of the architects of Mamdani’s stunning election last year, Katz confirmed to Blue Light News that he had ventured into British politics and described it as part of a global political struggle. He said he was there to offer members of the U.K.’s Labour and Green parties advice on mounting effective campaigns for elected office.

“The fight against the aligned interests of the oligarchy and the far right is an international one, and I’ll try to be helpful wherever I can,” the 26-year-old progressive political strategist said this week when asked about his February trip.

Among the players Katz met with: Rosie Wrighting and Gordon McKee, two Labour members of Parliament, and Rowenna Davis, a Labour politician running for mayor of Croydon, a town in South London. Katz confirmed Labour and Green operatives initiated contact and asked him to come over for the meetings.

Mamdani has emerged as something of a political beacon for progressive parties in other countries, including the U.K. and Canada.

The British left’s overture to Katz highlights how progressive movements around the world are looking at the Mamdani campaign’s populist playbook as ripe for replication. And it speaks to how elements of the American left increasingly see themselves as part of a global project.

Katz said he has continued to hold virtual meetings with members of both parties since returning stateside and plans to speak with Green leadership in the coming weeks.

The in-person sit-downs in the U.K., Katz said, revolved around his strategy and messaging techniques, with the U.K. politicians seeking to glean more insight into his overall approach. The Mamdani aide has become known for producing made-to-go-viral social media content highlighting progressive policy prescriptions for bread-and-butter issues like childcare costs.

Katz said his engagements in the U.K. were unpaid and that he’s not looking to start running campaigns across the pond this year, in part because he’s busy with the U.S. congressional midterms. But he expressed openness to working with progressives there on a paid basis in the future, opening the door to a key Mamdani adviser becoming an international political fixer.

Katz wouldn’t be the first U.S. progressive to help like-minded British politicians. Advisers to Sen. Bernie Sanders (I-Vt.) helped former Labour leader Jeremy Corbyn’s unsuccessful 2017 campaign for prime minister.

Drawing connections across different countries’ politics can be complicated, and while Mamdani’s high-octane style of campaigning can generate excitement in places other than New York, it’s not clear that everyone he met with on his travels overseas buys into his ideological project. Wrighting and McKee are prolific on social media platforms like TikTok, much like the New York City executive, but are mainstream Labour backbenchers.

Spokespeople for the Green and Labour parties did not return requests for comment about the meetings with Katz.

The Labour Party lost a key parliamentary election last week after the Greens, a much smaller party, ran a 34-year-old candidate who focused her campaign on tackling a spiraling cost-of-living crisis. The candidate, 34-year-old former plumber Hannah Spencer, has argued since her victory that it’s a winning message for the Green Party to continue emphasizing.

“We ran a hopeful campaign backed by thousands of volunteers and activists. We defeated the parties of billionaire donors,” Spencer wrote in an op-ed in The Guardian last week.

Sound familiar?

Mamdani defeated Andrew Cuomo, New York’s former governor, in last summer’s mayoral primary after aggressively centering his campaign around proposals aimed at making the city more affordable for working class New Yorkers.

The U.K.’s left-leaning parties, especially Labour following last month’s election setback, likely see Mamdani’s messaging model as something they can harness in future campaigns. That’s where Katz comes in.

Katz, who calls himself a populist politics “believer,” has been credited with spearheading the Mamdani campaign’s laser focus on promising to fight for a more affordable city by raising taxes on the rich to expand social safety nets, including making public transit and child care programs free. Though he hasn’t joined Mamdani’s administration, Katz is seen as very close with the mayor and continues to advise him on both governmental and political matters, joining him, for instance, for both of his high-profile meetings with President Donald Trump.

“The Brits can use some excitement in their politics,” Doug Muzzio, a longtime political scientist in New York who is not affiliated with Mamdani or his team, said when asked to opine on Katz’s U.K. moves. “So if Mamdani’s engaging style is something that can be replicated over there that would probably be very welcome.”

It isn’t unusual for campaign consultants to embark on a traveling road show abroad after successful domestic stints. Political advice is among the most American of exports: Chris LaCivita, Trump’s co-campaign manager, advised Sali Berisha of Albania’s opposition party after his 2024 White House run. Bob Shrum, the former Democratic presidential candidate adviser and speechwriter, advised Ehud Barak in Israel’s 1999 election for prime minister and the British Labour Party under former Prime Minister Tony Blair. And James Carville, the veteran political strategist, also advised Blair, along with having done work in more than 20 countries.

“A guy gets elected and they like you, and somebody calls: ‘Hey, somebody from such and such called us,’ and they’ll recommend people. I mean, it’s a kind of networking thing,” Carville said. “The perception is our political consultants are better than they actually are.”

But Katz’s adventures abroad likely say more about his principal than the consultant. Of Mamdani, Carville says: “He’s an object of curiosity.” In the same way that former President Bill Clinton’s popularity abroad juiced Carville’s prospects, Mamdani and his retinue are drawing longing glances from international compatriots.

“A lot of people hired me just to say we got Clinton’s guy,” Carville said.

And now more than ever, an appetite for progressive insights is sweeping Europe: Just last month, organizers of the Munich Security Conference hosted Rep. Alexandria Ocasio-Cortez (D-N.Y.), who in her remarks connected income inequality to the global rise of authoritarianism.

“Voters in democracies in Europe and elsewhere are responding to a lot of the same things that American voters are,” said Matt Duss, who advised Ocasio-Cortez on her Munich trip and is executive vice president at the progressive think tank Center for International Policy. “That’s a system of government that has not delivered for them, that they see as captured by special interests that are not responsive to their needs.”

Duss, who also previously served as foreign policy adviser to Bernie Sanders, said there is a global appetite for that brand of progressivism.

“I do think Bernie obviously has inspired a lot of colleagues in other democracies. Mamdani is a name that we hear a lot from our colleagues in Europe on the left,” Duss said. “People are watching and learning from each other. American progressives have things to learn as our colleagues in Europe innovate and vice versa.”

Going international is not without risks.

Witness, for example, Ocasio-Cortez’s reception in Munich, on-camera and widely clipped miscues on everything from mislabeling the Trans-Atlantic partnership the Trans-Pacific Partnership to suggesting Venezuela was below not above the Equator. (On the ground, leaders’ embrace of her was warmer than the social media maw.)

Were Katz to get officially involved in the U.S., he may not go at it alone. He is the co-founder of Fight Agency, a consulting firm made up of a number of veterans of the American progressive movement who could also get roped into working with him overseas. Among them: Rebecca Katz, an alum of former New York City Mayor Bill de Blasio’s administration who has managed a number of successful congressional campaigns in recent years.

Rebecca Katz, who is not related to Morris Katz, did not comment for this story.

Domestically, Morris Katz’s travels abroad posed some obstacles for a candidate in his stable.

“It was very hard to communicate with him and his team during the January, February timeframe, because he was over there,” said Nathan Sage, the former Iowa Senate candidate and Katz client who dropped out of the race in mid-February. “I have no idea what he’s doing. I have no idea what that is, but I do know that it was difficult.”

Despite that, Sage said he would recommend Katz’s firm to others.

John Johnston contributed to this report.