Socialism in one country
In his 1915 article "On the Slogan for a United States of Europe", Lenin stated the following: "...Uneven economic and political development is an absolute law of capitalism. Hence, the victory of socialism is possible first in several or even in one capitalist country taken separately. ...". After Lenin's death, Stalin adopted the theory and stated that the Soviet Union could survive without other socialist countries (in the West, such countries would be called communist states rather than "socialist countries"). This theory was contested by the Left Opposition within the party. Stalin's position gained an apparent confirmation from failed attempts of proletarian revolutions in other countries, and this might have also contributed to changing the focus of Stalin's external policy from the Third International to tradeoffs with capitalist states.
In the first edition of the book Osnovy Leninizma (Foundations of Leninism, 1924) (the one with his formula: Leninism is Marxism of the era of imperialism and the proletarian revolution), Stalin was still an adept of Lenin's idea that revolution in one country is insufficient. However, by the end of the same year, in the second edition of the book, his position started to turn into the opposite direction: "...proletariat can and must build the socialist society in one country".
Stalin later characterized Trotsky's position as asking the world to "wait" for Western workers and "simultaneous" global revolution. On the other hand, Stalin did provide aid to communists in other countries, most notably in the Spanish Civil War. Also, he established several "communist states" in Eastern Europe after World War II, although many communists (especially the Trotskyists), as well as many non-communists, argue that this action was motivated more by the desire to create Russian "satellite states" than to spread the workers' revolution. In any case, neither the supporters of Stalin nor those of Trotsky succeeded in starting a revolution in the West.
