Antisemitism is dramatically on the rise in America. On the streets of our cities, Jewish citizens are assaulted and severely beaten. On college campuses, Jewish students are so badly bullied by professors and classmates that 50% of them are now hiding their Jewish identity. Sadly, even a number of our sitting members of Congress have made overtly antisemitic statements. This surge in Jew-hatred is a threatening omen not just for Jewish Americans, but for all Americans—and, to be sure, the very idea of America itself. Antisemitism is frequently called "the oldest hatred" because of its millennia-long history. While its tenacity...