What role did Gorbachev play in the collapse of the USSR?

In hindsight, it is quite clear that the Soviet Union was already doomed in the early 1980's. It could not keep up with the West militarily nor economically, and it was increasingly unable to keep its populace blind from the outside world. The key factor holding the Empire together was the Red Army, and the threat of force. Gorbachev must have realized this and understood the need for major reforms. However, there was simply too much bitterness from years of oppression and brutality conducted by the regime. There were still generations which remembered those years, and the reforms, although probably in the right direction, came too fast and went too far. Had Gorbachev done nothing but simply towed the traditional party line, the USSR would have eventually collapsed because of its own impossibility. It can be argued that had he been more cautious with his reforms and introduced them more gradually, the Soviet Union could have survived intact, but that would have required a major reform of the bureaucracy and a crackdown of the rampant corruption, which the Soviet system had created and was infested with. The economic reforms failed and played into the hands of those who could best utilize them towards their own goals, and the situation of the ordinary people worsened even further. Gorbachev was responsible for the fact that the Soviet Empire disintegrated when it did. However, had he done nothing. The result might have been the same, except with more bloodshed and more chaos.