At the time of the last Moscow trial I remarked in one of my statements that Stalin, in the struggle with the Opposition, exploited the anti-Semitic tendencies in the country
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The October Revolution abolished the outlawed status of the Jews. That, however, does not at all mean that with one blow it swept out anti-Semitism
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These general historical conditions in themselves should make any thinking person realize that, despite the model legislation of the October Revolution, it is impossible that national and chauvinist prejudices, particularly anti-Semitism, should not have persisted strongly among the backward layers of the population.......

But this is by no means all. The Soviet regime, in
actuality, initiated a series of new phenomena which, because of the poverty and low cultural level of the population, were capable of generating anew, and did in fact generate, anti-Semitic moods......

http://www.marxists.org/archive/trotsky/works/1938/1...