HP. The reason Stalin was able to orchestrate his purging was because the rest of the Bolshevik Party thought he was a HP.
The Bolshevik Revolution would have been a success had they tossed away both Stalin and Trotsky.
Bolshevism was the implementation of a quack science, on a pile of corpses. The idea that it would have succeeded in the absence of Stalin means little. Whoever was in charge would have been killing people to stay in power, though perhaps not to the same extent.