Karl Marx made no detailed proposals for the structure of a socialist or communist government and society other than the replacement of capitalism with socialism and eventually communism by the victorious working class. Vladimir Lenin, the leader of the Bolsheviks, had developed the theory that a communist party should serve as the vanguard of the proletariat and ruling in their name and interest, but like Marx had not developed a detailed economic or political program. The new communist government of the Soviet Union faced alarming problems, such as extending practical control beyond the major cities, combatting counter-revolution and opposing political parties, coping with the continuing war and setting up a new economic and political system.