Soviet Union – Stalin becomes undisputed leader

In 1928, Stalin introduced the first five-year plan for building a socialist economy. In place of the internationalism expressed by Lenin throughout the Revolution, it aimed to build Socialism in One Country. In industry, the state assumed control over all existing enterprises and undertook an intensive program of industrialization. In agriculture, rather than adhering to the "lead by example" policy advocated by Lenin, forced collectivization of farms was implemented all over the country.

Under the doctrine of state atheism in the Soviet Union, there was a "government-sponsored program of forced conversion to atheism" conducted by Communists. The communist regime targeted religions based on State interests, and while most organized religions were never outlawed, religious property was confiscated, believers were harassed, and religion was ridiculed while atheism was propagated in schools. In 1925 the government founded the League of Militant Atheists to intensify the propaganda campaign. Accordingly, although personal expressions of religious faith were not explicitly banned, a strong sense of social stigma was imposed on them by the official structures and mass media and it was generally considered unacceptable for members of certain professions (teachers, state bureaucrats, soldiers) to be openly religious. As for the Russian Orthodox Church, Soviet authorities sought to control it and, in times of national crisis, to exploit it for the regime's own purposes; but their ultimate goal was to eliminate it. During the first five years of Soviet power, the Bolsheviks executed 28 Russian Orthodox bishops and over 1,200 Russian Orthodox priests. Many others were imprisoned or exiled. Believers were harassed and persecuted. Most seminaries were closed, and the publication of most religious material was prohibited. By 1941 only 500 churches remained open out of about 54,000 in existence prior to World War I.