"There can be only one" seems like a terrible way of looking at the world. But we have the habit of trying to look at causes in isolation, as if anything could happen in isolation. Even if we can't find more than one proximate cause for an event, we can find a cause for that cause and continue this back until our knowledge gives out. More often it looks like changing any one of a number of "causes" would have changed the outcome. Al Gore lost the White House because the media lied about him! No, because of the way he ran his campaign! No, because of Nader! No, because of the Supreme Court! No, because Florida Republicans broke the law! No, because of Gore's positions on gun control! No, because of Clinton's affair(s)! No, because Gore distanced himself from Clinton! No, because of the Southern Strategy! No, because the War on Some Drugs stripped citizens of the right to vote! No, because of the Electoral College! No, because at some point church leaders decided the Communist threat warranted a change in teachings! No, because the DLC abandoned most of America! No, because of Elián! Feel free to add your own, I'm starting to feel tired.