Anti-Semitism is hatred, fear, and hostility that harms, has harmed, or has the potential to harm Jews. The term anti-Semitism was coined in 1879 by German anti-Semitic agitator Wilhelm Marr, who claimed that the term was based on "science," rather than religious concepts that would have justified antagonism toward Jews. Yet antipathy toward Jews (sometimes known as Jew-hatred, Judaeophobia, or "the longest hatred") is centuries old, and centuries ago became elaborated into an ideology. Anti-Semitic ideology, whose adherents have drawn and continue to draw on anti-Jewish myth and legend, has led to social and legal discrimination, demagogic political mobilization, and spontaneous or state-sponsored violence that has striven to isolate, expel, or annihilate Jews as Jews. That ideology considers the Jewish character as permanently and unreformably degenerate. And as per that ideology, Jews, no matter how few or assimilated, are...