The Election: "History doesn't apply." Yes or no?

We must always remember history since it gives the general overview in what can happen in certain cirstances. But we cannot lock it in as if it is a natural law or something. Often, just one different cirstance can change an outcome. Like the Bin Laden tape supporting Kerry that came out just before the election. Without that tape, it is entirely possible that Kerry would have been elected. So when something has never happened before, like a black candidate actually making it to the candidacy, you can guess from past cirstances, but you cannot be sure.