Mayoral candidate Zohran Mamdani is in the midst of a “Five Boroughs Against Trump” campaign tour, asserting that it is “Trump billionaires who have been opposing our campaign’s vision for a city that New Yorkers can afford.”

Yet if he paid close attention to the residential neighborhoods of Queens and Brooklyn, he might learn the secret to housing affordability from a Trump — Fred Trump, that is, the president’s late father, described in his New York Times obituary as the city’s “master builder for the middle class.”  

Son of a German immigrant born at a Lower East Side Old Law tenement on Third Avenue, the elder Trump, as recounted by Thomas Campanella in “Brooklyn: The Once and Future City,” would build “more than 2,000 homes in Brooklyn between 1935 and 1942,” and “helped weave much of the fabric of outer-borough New York City.”

His importance is not just as history, however, but as a model for the “affordable” housing policy New York, and cities across the country, should still follow. He subdivided under-used former estates and farms to build small houses on small lots — the key to inherent affordability, without subsidy. (He did avail himself, at times, of government insurance). 

The first house he built at the Jamaica section  of Queens was typical: just 1,344 square feet. He sold homes with low down payments for as little as $3,000 to $7,500 — the equivalent of $71,000 to $179,000 today.

Even the quasi-mansion in which empire-builder Fred Trump lived with his family — including young Donald, until age 4 — was just 2,500 square feet, about the size of the median new home in America today, and it was built on a 4,800-square-foot lot, just a tenth of an acre. That small lot is a far cry from the half-acre zoning common today in suburbia, which pushes home prices sky-high. 

The elder Trump — like his son, a master promoter, who angered Robert Moses by mounting advertisements at the 1939 World’s Fair — built a range of housing types: bungalows, row houses, small Tudors. That allowed him to reach a range of economic classes.

Crucially, and unlike the public housing Mr. Mamdani advocates, these homes offered ownership and a vehicle for wealth appreciation. This has continued to be true long after their first sales. 

A prime case in point is the Hollis section of Queens, since the early 1960s a well-maintained enclave for the black middle class. As one resident — a Trinidadian registered Democrat with little fondness for President Trump — told the Times in 2015, “It’s a beautiful home. It’s really a strong house, it really is, I have to say that about it. He did a wonderful job.”

The elder Trump’s “Tudorvilles” type of housing was criticized by social critics such as Lewis Mumford, an intellectual father of high-rise public housing projects, as “bound to be ephemeral.”  Yet, per the historian, Mr. Campanella, the “Tudorvilles of outwash Brooklyn have endured, still affordable and remarkably resistant to all but the most egregious lapses of homeowner taste.”  

The commitment of individual small owners to their own properties is also, in other words, the key to their enduring maintenance — which has proved difficult to impossible for the public housing to which Mr. Mamdani is attached. 

The key to the elder Trump’s success lay not only in his feel for what his potential customers wanted in a house — he offered attractive small touches such as alley-based off-street parking — but in the ease with which he was able to build. He subdivided land formerly used to store animals and props for the Ringling Brothers’ circus and then “speedily” erected 400 homes, per Mr. Campanella.

The closest any current New York mayoral candidate comes to recognizing the importance of what builders call “as of right” construction today is the collection of ideas the incumbent, Mayor Eric Adams, calls his “City of Yes.”  

Mr. Mamdani has said the city can’t afford to “wait for the private sector” to build new housing — but, of course, it’s the city, with environmental reviews and NIMBY-ism, which causes the wait in the first place.

One wishes for the younger Mr. Trump to deliver a housing lesson by visiting Hollis or Jamaica Estates and celebrating his father’s accomplishments and their enduring significance. It would be a welcome addition to New York City’s housing affordability debate — and to the education of Mr. Mamdani.