During the reign of Joseph Stalin, the leader of the Soviet Union from 1928 to 1953, there were significant changes in the Soviet Union’s society and government. While Stalin was not a legitimate head of state, his reign turned the USSR into a totalitarian regime in which terror was Stalin’s most valuable political tool. After Stalin’s death in 1953, there were crucial reforms in society, political ideology, and economics under the new leader Nikita Khrushchev. Nikita Khrushchev (r.1953-1964) started a period of de-Stalinization in which he reversed many of the policies and ideologies that Stalin had imposed such as: industrial/agricultural economics, the purges, censorship, and isolationism as an international stance. This is known as the Khrushchev thaw.