I partially wanted to express it with "totalitarian state and lack of checks and balances". However, I slightly disagree. Being an authoritarian ruler, Gorbachev had lots of power. It is proven by the fact that his reforms were radical and unsuccessful, and many of the problems that the Soviet union faced during its demise were exacerbated by them. Of course, the Soviet Union was to suffer some losses but they could have been milder. But may be you are 100% correct. I don't feel knowledgeable enough on the topic of late Soviet union to argue.