Last weekend, I went to a small college in Pennsylvania to talk about history. I wanted to speak about the Jewish history that forged Israeli identity. It is a grim story, a tale of displacement and mass death, a story that explains much of the gap in worldview and politics between Israeli and American Jews.

I did not expect the history lesson to begin before I had even started my talk.

At the start of the event at Haverford College, over a dozen masked people wearing keffiyehs entered the lecture hall. It was a scene that has become dreary and familiar across American campuses and that I was told had become routine at Jewish student events at the elite college (cost to attend: $97,521 per year). Any minute now, the marching would begin, the chanting, the performance of intimidation, the masked pretense of doing something dangerous and courageous.