Talk politics.

Someone like Hitler. There were seventy million people in prewar Germany. Finding another Hitler would not have been difficult. Hell, there was a running rivalry among several viable leaders within the Nazi party, before Hitler killed all his competition. It's not like Röhm or Papen had radically different policies or were incapable leaders. And the Nazi party wasn't even the only crazy fascist movement in the game, similar groups were popping up everywhere at the time. Hitler came to power because Germany really wanted what he was selling, he filled a niche. Osama fills a niche, and to get where he is he had to scramble to the top amongst suitably similar opposition much the same way. They might have controlled the specific course of events, how much the Jews were persecuted vs. how much the homosexuals or which specific American seats of power got blown up, but the broad strokes depended on much bigger and less easily controlled historical forces. To undo WWII, you have to undo Versailles; Islamic fundamentalist uprising, the Cold War. How would a shorter Soviet invasion, culminating in an extended period under xenophobic Soviet rule, have made a different Afghanistan? Like I mentioned elsewhere, they're far from the only country all fucked up and run by bad dudes because of imperialist ventures.