The election of Zohran Mamdani as mayor of New York City marks a turning point in US urban politics, and its reverberations are already being felt well beyond the five boroughs.

To many on the American left, Mamdani represents hope: a democratic socialist, the son of immigrants, a man who speaks of fairness, affordability, and restoring dignity to those pushed to the margins of urban life. But to many others, especially within Jewish communities, his rise is deeply alarming.

From London, a city that has lived with a Muslim mayor for nearly a decade, the moment feels familiar. It also feels fraught.

It is worth stating at the outset that Sadiq Khan, for all the criticism he has faced, did not enter office with the same background of inflammatory or extremist statements as Mamdani. His political record was grounded in more mainstream Labour politics, and while he became a symbol of Britain’s multicultural ambitions, his own rhetoric rarely courted controversy of the kind now surrounding Mamdani.

As a life-long citizen of London, it is not clear even to me how responsible our mayor is for the alarming levels of antisemitism infecting our streets these days, nor how much of that responsibility is down to his Muslim identity. It shouldn’t matter what religion a mayor is, unless their religion influences their decisions in a way which runs counter to the wider society’s values and culture. But therein lies the problem — to trace the causes of almost intangible but very real cultural shifts and social tensions is virtually impossible in the moment.

Mamdani’s path to City Hall is undeniably historic. At 34, he is the youngest mayor in more than a century and the first Muslim to lead New York. His campaign energized hundreds of thousands — young voters, working-class immigrants, and a progressive base long disillusioned with establishment politics. His victory speech was filled with the language of empowerment: “This city belongs to you,” he told supporters, naming Yemeni bodega owners, Senegalese taxi drivers, and Mexican grandmothers among the architects of his movement.

Yet this language of inclusion exists alongside a record that many see as exclusionary, particularly toward Jews and supporters of Israel. Mamdani is a vocal supporter of the boycott, divestment, and sanctions (BDS) movement, which ultimately seeks to eliminate the world’s lone Jewish state. He has said Israeli Prime Minister Benjamin Netanyahu should be arrested in New York under an ICC warrant, refused to repudiate the slogan “globalize the intifada,” and once stated at a Democratic Socialists of America conference that “we don’t need an investigation to know that the NYPD [New York Police Department] is racist, anti-queer, and a major threat to public safety.” Jewish groups, moderate Democrats, and survivors of repressive regimes are right to be concerned.

The anxiety is not merely ideological. In the aftermath of the Hamas-led Oct. 7, 2023, Palestinian terrorist attacks on Israel, antisemitic incidents surged across the West, including in New York and London. In that atmosphere, Mamdani’s framing of the Israeli-Palestinian conflict in starkly anti-Israel terms, with no serious reckoning with the brutality of Hamas, struck many as morally evasive at best and hostile at worst. His critics question his judgment, and they are not wrong to do so.

In the UK, we have lived through some of these debates with Khan. London’s mayor is a Muslim of South Asian heritage, and Mamdani, though born in Uganda, is of Indian heritage through both parents. Khan speaks in the register of cosmopolitan liberalism. His supporters celebrate his ascent as proof of Britain’s openness. His critics, especially outside London, view his leadership as symbolic of a city that has drifted away from national cultural norms. Though no credible evidence links Khan’s policies to religious ideology, the perception of an unspoken alignment with Islamist grievances has persisted among some critics.

This perception has been shaped by moments that transcend formal policy. Public Ramadan displays in central London, including large-scale installations inaugurated by Khan, have been celebrated as signs of inclusivity, but many argue that Christian festivals have not received similar visibility. In late 2024, a halal-finance advertising campaign run across London’s transport system, ultimately regulated by Khan, featured provocative imagery and religious overtones, prompting accusations that public space was being used to promote a particular faith’s commercial ecosystem.

The truth is people might be less concerned about religious adverts from other faiths which they perceive as less aggressively set on conquest and conversion — an uncomfortable but worthwhile thought to keep in mind. London along with other major UK cities has also seen numerous intimidating street protests where Muslim men have worshipped in the street, paraded terrorist flags, and even burnt a car whilst holding a Quran aloft on top of a police van (in Leeds last week).

This current climate matters. And these perceptions, however incomplete or distorted, matter. They cannot simply be dismissed as racist or xenophobic, and doing so is counterproductive. The fear many Jews feel in New York today is not an invention either. It is not merely a media creation. It is based on real experiences, real statements, and a broader climate in which antisemitism is often recast as political critique. But nor should these concerns be weaponized with reckless rhetoric. We have seen in Britain how public discourse can descend into paranoia when criticism is expressed in conspiratorial or racially charged terms. If critics of Mamdani wish to be heard, they must be precise, restrained, and grounded. Otherwise, they will be shouted down by the very people they hope to persuade.

Khan himself has sometimes contributed to the perception of grievance politics. In April 2024, he apologized to Britain’s Chief Rabbi for implying that criticism of his position on Gaza was influenced by his Muslim-sounding name. He admitted that he felt held to a different standard due to his faith, but accepted that his comment was unfair. There is a broad unease about how religion, ethnicity, and political critique intersect in public life, and pretending otherwise will not help allay people’s fears.

What happens next in New York is impossible to predict. As in London, the city’s institutional constraints, budgetary realities, and legal frameworks will limit how much any mayor can reshape it. But politics is not just about budgets or buses. It is about the values a city embodies, the identities it elevates, and the signals it sends to its people. In electing Mamdani, New Yorkers have made a powerful statement. Whether that statement fosters solidarity or division will depend on how he governs, and how his critics respond.

London may offer some lessons, but it is not a template. The United States and the United Kingdom differ in their histories, their social structures, and their ideological battle lines. Still, both countries are wrestling with similar questions: What happens when the politics of social justice collide with the politics of ethnic identity? Can a city led by a figure deeply polarizing to one community still represent the whole?

We do not yet know how this story will unfold. But we should pay close attention. New York is not just another city. It is, in many ways, the stage on which the future of liberal democracy will be tested. And its new mayor stands at the very center of that test.