The Workers' Party of Marxist Unification was a Spanish communist party formed during the Second Republic and mainly active around the Spanish Civil War. It was formed by the fusion of the Trotskyist Communist Left of Spain and the Workers and Peasants' Bloc against the will of Leon Trotsky, with whom the former broke.

Stalinism is the totalitarian means of governing and Marxist–Leninist policies implemented in the Soviet Union (USSR) from 1927 to 1953 by dictator Joseph Stalin. Stalin had previously made a career as a gangster and robber, working to fund revolutionary activities, before eventually becoming General Secretary of the Soviet Union. Stalinism included the creation of a one man totalitarian police state, rapid industrialization, the theory of socialism in one country, forced collectivization of agriculture, intensification of class conflict, a cult of personality, and subordination of the interests of foreign communist parties to those of the Communist Party of the Soviet Union, which Stalinism deemed the leading vanguard party of communist revolution at the time. After Stalin's death and the Khrushchev Thaw, a period of de-Stalinization began in the 1950s and 1960s, which caused the influence of Stalin's ideology to begin to wane in the USSR.