There are good and bad ways to start an administration, then there’s the way Zohran Mamdani did it. Dreadful, awful and horrible don’t fully capture his First Day fiasco. No political guru in the history of New York elections would advise a new mayor to launch his administration by picking a fight with Israel and adding fresh evidence to the suspicion that the city’s first Muslim mayor is an antisemite. Yet that’s exactly what Mamdani did by announcing that he had rescinded all the executive orders of his predecessor, Eric Adams, going back 15 months. Some were inconsequential, but two...