The frontrunner in the New York mayoral race, has a lot of bad ideas.

Soon after Zohan Mamdani won the Democratic primary, John Catsimatidis, owner of New York City’s 2 oldest and largest independent supermarket chains, wrote an op ed for the Wall Street Journal. In it, he warns about what is probably the worst of the candidate’s campaign promises: “a government-run alternative to private supermarkets.” Mr. Mamdani calls this a “public option” and he wants to start with five stores, one in each of New York’s boroughs.

Mr. Catsimatidis points out that, in Venezuela and Cuba, nationalization of food distribution brought poverty, rationing, and hunger. He writes of citizens standing in lines “for hours to get a loaf of bread or a bag of rice — if there was any food left at all.”

Washington Post columnist Megan McArdle says Zohran Mamdani’s stated goal is “to help bring prices down and provide oases in the city’s ‘food deserts’.” Food deserts? Ms. McArdle says “There’s no obvious food gap for the city to fill” and points out that “almost everyone in the city has at least one grocery store within walking distance.” And as for promises of lower prices: she describes the grocery business as “one of the most hypercompetitive and efficient parts of our economy, with profit margins that have historically averaged around 1 to 3 percent.”

Mr. Catsimatidis reiterates: “Supermarkets operate on thin margins, complex logistics, and decades of supply chain expertise.” He wonders “Who is going to manage these public grocery stores? The same government that can’t fix subways or public housing?”

The reality is that city-appointed bureaucrats would end up selling groceries at a loss, subsidizing even wealthy New Yorkers and imposing huge costs on taxpayers. The phrase “No profit motive” may sound benevolent, but like Mr. Mamdani’s promises to freeze rents and offer free bussing, public supermarkets would only serve to remind New Yorkers of socialism’s devastating consequences.