Philip Slayton’s latest book is Antisemitism: An Ancient Hatred in the Age of Identity Politics. On Monday more than a thousand Israeli troops, backed by military bulldozers and armed drones, descended on a large Palestinian refugee camp in the West Bank city of Jenin. Their intent was to destroy militant armed groups and independent militias using the camp as a headquarters. At least 13 Palestinians were killed and 120 injured during the Israeli raid, which left one soldier dead. Meanwhile in Tel Aviv, in a so-called “tit-for-tat” revenge attack, nine people were wounded by a Palestinian in a car-ramming and...