It was stated in the book that “The real force that ended the Soviet Union itself and most especially in the expectations and plans of the new reform leadership that came to power in 1985.” This event led to Mikhail being elected and trying to make new policies, but it didn’t work the way he wanted.
Nationalism was a threat to the Soviet Union, just like what the book said, “"That tenacious nationalism, more than any other factor, crushed their hopes for reform and destroyed the Soviet Union.” That is why I believe that communism went out with only a whimper and not a bang.