Commentary: American Jews always believed the U.S. was exceptional. We were wrong.

I am a historian of American Jews. My morning last Saturday began with a bar mitzvah at our synagogue in Philadelphia; an hour into it, I left with my son to take him to a squash lesson at a private club. In my profession, we call this “the American-Jewish synthesis”: the ability to be Jewish and American all at once. Historians like me have spent decades explaining how and why Jews have been able to achieve this.Then I saw the news of the Tree of Life shooting in Pittsburgh. In my u