A far-left New York state assemblyman, Zohran Mamdani, is surging in New York City’s mayoral primary polls due in part to his vow to “freeze” rents for many city apartments. Victory in the race for the Democratic nomination is tantamount to putting Mr. Mamdani on a glide path toward Gracie Mansion. Even if he wins, though, would the Supreme Court allow his “rent freeze” to go into effect?

One would think not, based on a plain reading of the Constitution. The Fifth Amendment’s Takings Clause forbids any “person” to be “deprived of life, liberty, or property, without due process of law,” and the parchment disallows any “private property” to “be taken for public use, without just compensation.” Mr. Mamdani’s scheme to bar landlords from raising their rates in rent-stabilized apartments would seem to run afoul of these provisions.

Critics are warning that Mr. Mamdani’s plan would be a disaster. Implementing his rent freeze, a former lieutenant governor of New York, Betsy McCaughey, warns, “would turn the entire city into a slum, with dilapidated, abandoned buildings and thousands of occupants forced to live in squalor because their apartments are no longer maintained.” A New York Post editorial calls Mr. Mamdani’s ideas “fantasy economics, pure and simple.”

Yet the socialist siren song of a rent freeze appears to be convincing many would-be primary voters to back Mr. Mamdani, with a new poll showing the assemblyman within 10 points of Governor Cuomo after multiple rounds of ranked-choice voting — the means by which the primary will be decided. In the first round, the polls finds Mr. Cuomo leads with support from 35 percent of Democrats, with Mr. Mamdani in second place with 23 percent.

Mr. Mamdani, too, has just earned the endorsement of the leftist Working Families Party, which could boost his prospects among the liberal wing of the city’s Democratic Party. The noble comrades of the Working Families Party, Gothamist reports, “are inspired” by Mr. Mamdani’s grab-bag of government handouts and benefits like “free buses, city-run grocery stores and freezing the rent for stabilized tenants.”

Mr. Mamdani’s campaign website gripes that “a majority of New Yorkers are tenants, and more than two million of them live in rent stabilized apartments.” He avers that “these homes should be the bedrock of economic security for the city’s working class,” but that Mayor Adams’s “hand-picked appointees to the Rent Guidelines Board” have been “jacking up rents on stabilized apartments by 9% (and counting).”

With inflation having jumped some 20 percent since 2021, when policies launched by President Biden and congressional Democrats sparked a wave of price increases, what would Mr. Mamdani have the city’s landlords do to cover their higher costs? The assemblyman, defying the laws of economics, says if he is elected he would “immediately freeze the rent for all stabilized tenants,” while aiming to build more housing and “bring down the rent.”

Yet what builders or property owners would be so naive as to invest their capital in apartments knowing that New York’s socialist government would limit their ability to make a profit? That would risk a repeat of New York’s past experience, when it neared bankruptcy in 1980 because landlords “often abandoned their buildings, removing them from the tax rolls,” journalist Ken Auletta reported, because they “were not getting a return on their investment.”

The Supreme Court in 2024 declined to take up two cases that sought to challenge New York’s rent control regime. Imposed as an emergency measure during the World War II era, rent control has been distorting the city’s housing market for decades. Lawsuits called rent control “appropriations of an owner’s fundamental property rights” and pointed to the high court’s ruling in Cedar Point Nursery v. Hassid, which involved restrictions on farmland.

The Supreme Court’s disinclination to weigh in on New York’s rent control system, though, could have been based on the premise that landlords were at least allowed to raise the rents by the amounts permitted by the Rent Guidelines Board. If Mr. Mamdani succeeds in further crimping the constitutional rights of New York property owners, one can imagine the high court wanting to take a closer look at such a government taking.