During and after World War II a great variety of violent conflicts and protest movements broke out behind the lines of the Wehrmacht and the Red Army all along the western and southern borderlands of the European part of the Soviet Union. To define and analyze them politicians, publicists, historians, and social scientists have employed a number of concepts: resistance and collaboration, Shoah or Holocaust, ethnic cleansing, deportation and forced resettlement, wars of national liberation, partisan or revolutionary warfare, and internal wars. Each of these has given rise to a vast literature and the concepts themselves have undergone refinements and permutations. But there have been fewer attempts to perceive them as parts of a larger phenomenon or to reveal the linkages that connect them all. The purpose of this essay is to suggest that the concept of civil war can provide this missing integrative function.