I think that there are probably many reasons. Probably the most relevant within the states is that the figure of Stalin allows for a sort parallelism of totalitarians argument of which probably Arendt's is the most sophisticated version. The sort of 'cold war' thinking that you are so quick to reference. There is also a version of history created by Kruschev that is neccessarily directed towards shrinking his role in the time period. The Trots pick up the sort of animosity towards Stalin through the hatred of the old man. Finally, it's not totally wrong. I think that the authority that Stalin took in the party is much stronger than the first amongst equals role that Lenin played. I don't think that the Thermidor thesis is completely wrong in its emphasis of the destruction of the party. Robert Wood