A gunman opening fire at a Pittsburgh synagogue on Saturday, killing 11 and wounding six, was the deadliest mass shooting of Jews in America. But the anti-Semitism it represented wasn't new at all, Jeffrey Herf, distinguished university professor of history, said in The Washington Post yesterday. In an op/ed, he laments the ignorance of President Donald Trump and the nation about how anti-Semitism works.

On the evening after the deadliest act of violence against American Jews, President Trump said that Jews had “endured terrible persecution” for centuries: “You know that. We have all read it. We have studied it.”

But his response to the horrific news that a gunman had killed 11 people and wounded six at Shabbat services at the Tree of Life synagogue in Pittsburgh made it clear that Trump doesn’t actually understand the nature of anti-Semitism at all.

Read the full op/ed here.