This study examines the effects of the civil war on the Soviet political process. Methodologically, it is an attempt to combine a study of political ideas and institutions with a study of popular movements and interpret the development of the Soviet political system. The main focus is on the Communists’ interaction with the opposition parties: the Social Democrats (Mensheviks) and the Socialist Revolutionaries. The study traces the destruction of opposition parties in Lenin’s Russia. It aims to be a contribution to the understanding of the origins and nature of Stalinism.