Bolshevik leaders had effectively reestablished a polity with roughly the same extent as that empire by 1921, however with an internationalist ideology: Lenin in particular asserted the right to limited self-determination for national minorities within the new territory. Beginning in 1923, the policy of "Indigenization" was intended to support non-Russians develop their national cultures within a socialist framework. Never formally revoked, it stopped being implemented after 1932. After World War II, the Soviet Union installed socialist regimes modeled on those it had installed in 1919–20 in the old Russian Empire, in areas its forces occupied in Eastern Europe. The Soviet Union and later the People's Republic of China supported revolutionary and communist movements in foreign nations and colonies to advance their own interests, but were not always successful. The USSR provided great assistance to Kuomintang in 1926–1928 in the formation of a unified Chinese government (see Northern Expedition). Although then relations with the USSR deteriorated, but the USSR was the only world power that provided military assistance to China against Japanese aggression in 1937-1941 (see Sino-Soviet Non-Aggression Pact). The victory of the Chinese Communists in the civil war of 1946-1949 relied on the great help of the USSR (see Chinese Civil War).