In an interesting essay in the new issue of World Affairs, Joshua Muravchik looks back at the year 1989 with two decades of perspective. Only the first few paragraphs of the piece are available online, but Muravchik does make a fascinating claim:
The axis would have been defeated without Roosevelt and even without Churchill, although Britain might have fallen first. India would have gained independence without Gandhi. Segregation would have ended in America without Martin Luther King Jr. But would the Soviet empire have dissolved, the Cold War ended, and Communism been repealed--all the blessings achieved peacefully--without Gorbachev? I don't think so.
Muravchik goes on to say that even though the Soviet economy was pathetic, it had nevertheless survived in its pathetic state for decades. And the Red Army was still a force to be reckoned with. As for his comparisons, I think Muravchik might be slightly unfair to Churchill here, simply because without his (Churchill's, not Muravchik's) presence in the British government, it is not at all clear what role Britain would have played during the war. Nevertheless, Hitler was probably not going to defeat the United States and the Soviet Union. Gandhi and MLK Jr. were brilliant tacticians and heroic men, but it is debatable how much they moved history forward. British control of India was coming to end with or without Gandhi's nonviolence movement, especially considering Britain's postwar standing. As a colleague points out, the great legacy of both men is the manner in which they led their movements.
Anyway, Muravchik's case for Gorbachev is very convincing. It is hard to envision a scenario whereby the Soviet Union would still be functioning today, but what if the Soviet General Secretary had decided to put down the revolutions in Europe with force? Who is to say that Soviet Communism would not have lasted another decade? Of course this speculation is all good fun--and completely unprovable. If you get your hands on the print version of Muravchik's article, it is worth reading in full.