John Ketcham is director of Cities at Manhattan Institute.

Last month, New York City Mayor Zohran Mamdani announced that he will take “aggressive legal action to remove negligent owners and property managers,” transferring buildings “that have suffered chronic neglect” from bad landlords to “responsible stewards” — a coalition of nonprofits and tenant groups aligned with his base.

He neglected to mention that, five decades ago, New York City tried something very similar, taking possession of abandoned properties and eventually turning many of them over to nonprofits. Public control didn’t make them viable; instead, the city became the state’s largest slumlord.