In responding to the Hamas attack, some world leaders have directly connected the past to the present in stark terms, speaking to the sense of trauma felt by many Jewish people around the world. Biden has mourned what he called “the deadliest day for Jews since the Holocaust” and decried the Hamas assault as “barbarism that is as consequential as the Holocaust.” Netanyahu likened the killings at a music festival to the Babi Yar massacre of 1941, when more than 33,000 Jews were killed over the course of two days in Kyiv, the capital of Ukraine. “I understand on a...