The political drama of the week—the revelation that, in 1995, Donald Trump claimed nine hundred and sixteen million dollars in losses and as a result might not have had to pay any federal income taxes for two decades—was a New York story in every particular. Its theme was the comeuppance of the capital class by the hand of brainier, laboring professionals. It had a midtown office-tower setting and an earnest protagonist, the Times metro reporter Susanne Craig, who found Trump’s tax returns because she is a compulsive checker of her newsroom mailbox. It had a vengeful ghost: whichever shrewd, jilted ex-wife or shrewd, jilted ex-C.P.A. photocopied the returns and sent them to the press in the first place. And, at the center of it all, there was an eighty-year-old real-estate accountant named Jack Mitnick.

Mitnick functioned both as the story’s narrative pivot and its moral anchor. His signature was on one of the tax forms sent to the Times, and the paper’s reporters tracked him down in Florida, where Mitnick now lives in semiretirement, to try to confirm that the documents were authentic. Mitnick was wary, but eventually he agreed to meet a reporter in a bagel shop. The Times describes the scene: “ ‘This is legit,’ he said, stabbing his finger into the documents.” That “stabbing” is a nice flourish. It describes, after all, the story’s essential plot.

If Mitnick had been hesitant with reporters at first, he quickly grew more forthcoming. He’d spent his career practicing at a Long Island accounting firm that specialized in helping the great New York real-estate families hold on to their wealth. He’d been Fred Trump’s accountant, and when Donald became an adult Mitnick did his taxes, too, for more than thirty years, until 1996. On one of the documents that the Times received (the paper was sent only the first pages of Trump’s 1995 New York, New Jersey, and Connecticut returns), the nine-figure amount entered under losses had looked unusual: the first two characters had been entered in a different font. Mitnick solved that mystery. The tax software he’d used at the time only allowed him to enter seven figures in the loss column (not unreasonably, it had probably not anticipated anyone claiming nine-figure losses), so he had added the first two digits with an I.B.M. Selectric typewriter.

Perhaps Mitnick sensed that there was a grander role for himself in this story: not just the clerk who verifies the papers but the counsellor as character witness. He told the Times that Donald Trump was brash and undisciplined, so unlike his scrupulous father, Fred. When Trump and his wife Ivana would come into his office to go over the returns, Mitnick said, it was almost always Ivana who asked more questions. On Wednesday, CNN interviewed Mitnick on air via satellite and asked him about the Trump campaign’s argument that avoiding taxes meant Trump had dealt with the tax code “brilliantly.” Mitnick said that Trump had “virtually zero” role in preparing his own taxes. His only contribution was to hire Mitnick. Here, Mitnick gave a grin. He was enjoying himself. “Those returns were entirely created by us,” Mitnick said.

Spotting the New York in Donald Trump’s Presidential campaign is easy, if you keep in mind the New York in which he made his name, during the nineteen-seventies and eighties, and if you imagine that New York as it was perceived through the tinted windows of a Lincoln Town Car headed to the airport, Don Imus on the radio. The racialized talk of crime and instability; the palpable feeling of threat; the ethnic-essentialist talk of “the blacks.” Seen this way, Trump’s primary campaign issues—law and order, and trade—seem retro. In early speeches last year, he sometimes invoked the villainy of the Japanese. And beyond this campaign Trump has long appeared to work from the belief that even the most prosperous and cosmopolitan of places can feel themselves vulnerable to outsiders, and subject to a kind of knee-jerk nativism. “I’ve always said that New York is the greatest city on earth, and I’m giving native New Yorkers the guarantee it will remain our city,” Trump said in 1994, when he briefly cut a deal to buy the Empire State Building from a Japanese investor named Hideki Yokoi. “This solidifies me as New York’s native son.”

Many native New Yorkers are born lucky, but in the city’s real-estate families the condition is extraordinary. The city’s real-estate industry has long been as dynastic as any, featuring the kind of insular, old-school arrangements in which billionaires sometimes personally take calls from tenants. In Trump’s lifetime, the properties held by New York’s real-estate families have gone from being the objects of longing of a local aristocracy to those of a national one, and then an international one. There is something familiar about Mitnick’s position, the expert who explains that wealth in New York is often built not on talent but on dumb luck and greed. It’s the story of Harry Markopolos, the hero of the Bernie Madoff episode, or Bradley Katsuyama, who in Michael Lewis’s book “Flash Boys” exposed the bias in high-frequency trading. If the Mitnick episode revealed anything about Trump, it was the direction of his narcissism, that he could take credit for an employee’s expertise as if it were a condition of his own character.

The old stories about Trump’s ascendance in New York are reminders of how different the city was then, of how much has since been upended. “Donald was like an overgrown kid, all rough edges and inflated ego,” Marie Brenner, of Vanity Fair, once wrote, recalling the real-estate heir’s arrival, in 1980. His suits were “badly cut, with wide cuffs on his trousers,” she wrote, and he rode in a “silver Cadillac with ‘DJT’ plates and tinted windows and had a former city cop for his driver.” The part of the city that mattered seemed so tiny to Trump then that it could be enclosed in a single section of a restaurant. “Anybody who’s anybody sits between the columns,” Trump told Brenner back then, sitting at the “21” Club and gesturing. “The food is the worst, but you’ll see everybody here.”

No longer. The schmoozers and deal makers have to share financial clout with the quants, the political machers with the organizers and ideologues, and power of all sorts has become more diffuse. It is a city of Mitnicks as much as of Trumps. For all the heavy talk in this Presidential election about the alienation and suffering of the heartland, the headquarters of the two major parties’ Presidential campaigns are separated only by the East River. Certain dynamics are more local. Political power has flowed out of plutocratic Manhattan, where Trump’s campaign is sited, to professional Brooklyn, where Clinton’s is. The psychological mystery of this campaign is what wound ran so deep in Trump that it so sensitized him to displacement, decline, and anger. It looks a bit clearer from the local angle. Trump’s city isn’t his any longer. What he lost was New York.