Why have churches in the U.S.S.R. been harassed in recent years? It has been supposed by many that if Stalin stopped most persecution during the Second World War, then things under Khrushchev could only improve. Instead they deteriorated, and all liberties of Soviet citizens received more respect except the religious.A common answer has been that the Soviet authorities were horrified by the continued hold of religion which they considered to be a threat to Marxism. Such a view is quite popular in the west where a clash of ideologies, with Christianity triumphing over Marxism, consoles churchmen who cannot find such a triumph in their own society. But this assumes that the Soviet rulers consider Christianity to be a religion based on certain tenets, and as Marxists they cannot be expected to do so. For them religion is primarily an instrument of social control.
Olga Kucherenko, Soviet Street children and the Second World War: Welfare and Social Control under Stalin