In his race for mayor, Queens Assemblyman Zohran Mamdani has done the impossible: He’s made Andrew Cuomo look like a safe, stable choice. Mamdani pulled off the remarkable feat by breaking a cardinal rule of politics: Don’t scare people. But he has done exactly that by taking such radical positions in the Democrats’ mayoral primary that the portion of the electorate that hasn’t fallen for his vision of a socialist utopia realizes his policies would wreck New York. His mantra of free this and free that, combined with a rent freeze on 1 million privately owned rent-regulated apartments, while promising...