Monday began peacefully enough at New York University, where I am a faculty member at the medical center. In contrast to many other major universities, NYU lacks a central campus. When it comes to the volatile demonstrations here, at Columbia University and around the country, not having a central collecting place for encampments is actually an advantage. Many NYU students consider Washington Square Park their equivalent of a green, even though it is public property patrolled by the police. Previous dueling protests in the park for Palestinians or Israelis remained for the most part peaceful. Unfortunately, during the most recent...