I know very little about Bulgakov but a fair bit about Stalin. How much of it is about the mid-late 1930s (Yezhovshchina)? The novel was over a decade in the making, so including the end of the NEP period and Stalin's ascension. I guess by union, sojourner, you're referring to the organisation of 'cultural' workers and with its tighter control the squandering of talent possessed by Bulgakov and others?
In real life, did he and others really believe it was Stalin himself who was personally behind some of the censorship and interference in their affairs rather than appearing weak in the face of bureaucrats with their own agendas? There are plenty of people from all walks who contacted, or tried to contact, Stalin personally for his intervention in certain problems related to their work or quality of life.
I guess I'm trying to understand how they saw Stalin, his dictatorship through the party, the legitimacy of socialism in the USSR and the use of terror to defend it.