When historian Deborah Lipstadt defeated a libel suit brought against her in a British court by Holocaust denier David Irving in April 2000, it was almost possible to imagine that antisemitism might someday become a thing of the past, at least in much of the West. Taking a trip to Israel was not an ideologically fraught choice. Wearing a Star of David was not a personally risky one. College campuses did not feel hostile to Jewish students. Synagogues (at least in the United States) did not have police officers stationed outside their doors. Not anymore. The Anti-Defamation League recorded 751...