Over the last few months I have argued, in a number of different contexts, that in analysing the defeat, degeneration, etc. of "the left" in any given context, it is almost *always* wrong to begin one's search by focusing on the left. Defeats of the left have almost always been due not to any mistake or set of mistakes, betrayals or any set of betrayals, but to the strength of capitalism at this time.
In considering the history of the FSU from 1917 to its dissolution, the point of departure is the cold/hot war(s) launched against the Soviet Union by capital. Analogy: a few weeks ago I happened to tune in a tennis tournament on tv, and during the few minutes I watched it I picked up what seem to me to be possibly useful terminology in judging the left: the announcer distinguished between "forced" and "unforced" errors.
The assumption of the Soviet Union's doctrinaire critics is that all its errors were of the latter kind, "unforced" and internal to the revolution. This may have been the case, but I think the burden of proof rests on those who maintain this position. Without *strong* evidence to the contrary, the point of departure should be that the SU's errors/crimes etc. were *forced* errors. It was doomed from the start, regardless of what policies the leadership adopted or didn't adopt. For it to survive for 70 years constitutes an astonishing success, utterly unpredictable in 1917.