Anti-Semitism has a violent, ugly history dating back into the Middle Ages in Europe. It later became an integral part of Nazi and fascist ideology in Europe, and of organizations like the KKK in the United States—though less violent but pervasive forms of it acted as the ground on which more extreme versions of it could grow. In recent years, Muslims have replaced Jews as the far right’s preferred scapegoat. But anti-Semitism lurks in the shadows, and remains a potent and dangerous part of far-right ideology. In the past several years there has been a marked increase in anti-Semitic incidents worldwide. Organizations like ISIS and al-Qaeda have also fanned its flames, conflating hatred of Jews and opposition to Zionism. But most who oppose Zionism are not anti-Semites—but consistent opponents of all forms of oppression and discrimination.