This view is challenged by Stalinists and their followers, who claim that socialism was established in the Soviet Union after Joseph Stalin came to power and instituted the system of five year plans. The 1936 Constitution of the USSR, known as the Fundamental Law of Victorious Socialism, embodied the claim that the foundations for socialism had been laid.[72] Joseph Stalin introduced the theory of Socialism in one country, which argued that socialism can be built in a single country, despite existing in a global capitalist economic system.