ENIn the long history of forced migrations the twentieth century stands out as the period when all earlier expulsion practices crystallized into a complex and continuous phenomenon. It is in the twentieth century that repressive population transfers became an ordinary practice to accompany wars, revolutions, and collapse of empires and multinational states. The motivational side of forced migrations in the twentieth century displayed much more diversity than ever before. The Gordian Knot of ideological dogmas, geopolitics, national security doctrines, socio-economic transitions and modernization processes provided fertile soil for the blossoming of this brutal phenomenon. The after effects of repressive resettlements in the first half of the twentieth century echo nowadays in ethnic and religious cleansings in the republics of the former USSR and Yugoslavia. In this sense, forced migrations and their consequences form a vicious circle, the fruit of which are still to be harvested by future generations. They were practiced by the Imperial and, especially, Soviet governments on a colossal territory from the Baltic Sea to the Pacific Ocean. Whole nationalities such as the Koreans, the Volga Germans, the Crimean Tatars, the Chechens, the Ingush, and others were uprooted and totally resettled. Forty-eight other nationalities were partially deported and millions of people lost their homeland. In scrutinizing each particular example of a large-scale deportation operation conducted in Russia or the USSR from 1915 to 1953 from the motivational viewpoint, one will inevitably observe a combination of ideological, geopolitical, economic and other factors that influenced the decision-making. At the same time, surprisingly often those factors were self-excluding. What at first sight seems to be a rigidly devised policy of the government reveals systemic controversies and deficiencies in practice in the course of deeper analysis.