Socialism in one country
The Socialism in one country theory is the foundation of Stalinist socialism. The theory is in opposition to Lenin's beliefs that while a revolution may happen in one country, the final success of socialism in one country, especially in such a backward one as Russia is impossible without proletarian revolutions in other, advanced countries of Western Europe. Mensheviks and Trotsky also came to the same conclusion, basing on Trotsky's theory of Permanent Revolution, disputed by Lenin.After Lenin's death, Stalin put forward the theory that the Soviet Union could survive without other socialist countries, against the Left Opposition within the party. His position gained an apparent confirmation from failed attempts of proletarian revolutions in other countries and possibly changed 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 is still an adept of Lenin's idea that revolution in one country is insufficient. However by the end of the year, in the second edition of the book, this position started to turn into the opposite direction: "...proletariat can and Must build the socialist society".
While the Communist system eventually collapsed, there have been no communist revolutions in any of the advanced countires in Western Europe or America in the interim. Where communism still survives, at least in name, it has done so by wholesale adoption of capitalism as in the People's Republic of China or Vietnam or by repressing its citizens along the lines used by Stalin in North Korea. In the long term it seems neither Lenin nor Stalin was correct.
See also: