The 1917 Russian Revolution overthrew a centuries-old regime of official antisemitism in the Russian Empire. The success of the Soviet Union in dealing with this previous legacy of antisemitism, as well as the extent that the Soviet government fought against this prejudice, is a topic of some debate. Although officially forbidden as a form of ethnic and racial chauvinism, antisemitism came to be commonly used as an instrument for personal conflicts in the Soviet Union, starting from conflict between Joseph Stalin and Leon Trotsky (who was Jewish) and continuing through numerous conspiracy theories spread by official Stalinist propaganda. Antisemitism in the Soviet Union reached new heights after 1948 during the campaign against the "rootless cosmopolitan", in which numerous Yiddish-writing poets, writers, painters and sculptors were killed or arrested. This culminated in the so-called Doctors' plot, in which a group of doctors (some of whom were Jewish) had allegedly conspired to murder Stalin.
Under the Tsars, Jews – who numbered approximately 5 million in the Russian Empire in the 1880s, and mostly lived in poverty – had been confined to a Pale of Settlement, where they experienced prejudice and persecution, often in the form of discriminatory laws, and had often been the victims of pogroms, many of which were organized by the Tsarist authorities or with their tacit approval. As a result of being the victims of oppression, many Jews either emigrated from the Russian Empire or joined radical parties, such as the Jewish Bund, the Bolsheviks, the Socialist Revolutionary Party, and the Mensheviks. There were also numerous antisemitic publications of the era which gained widespread circulation.