Because, once again for emphasis, bush II and Karl Rove never won an election. Despite massive fraud, they lost both times. The American people had either the good sense to not bother voting at all (which isn't really all that effective a way to ensure one's proper political representation but it at least signifies that you're not impressed with the available alternatives) or they voted for the lesser of two evils.
All the crimes and bunglings of the bush II regime are the responsibility of a minority of the US-American electorate and a corrupt cabal of militarists and corporate gangsters. Which is why the US-American people should have risen up and prevented this gang from ever getting started on their road to historical infamy.
I say all this in the looming shadow of a possible majority government for the murderous and murderously incompetent Conservative Party of Canada of Stephen Harper. This inhuman nitwit shouldn't even have a minority government, but thanks to our freakishly outdated electoral system he does have one. At least there's enough democratic strength left in the system that he's been forced to water down the extent of his and his party's lunatic fantasies. If it turns out to be the case this time that vote-splitting on the left permits the party of the fascist closet-cases and hypocrites, the selfish and the comfortably ignorant, to win majority government status, then we're all in trouble. But the damage that Harper (the enemy of health care and the fan of killing innocent people in other lands) and Flaherty (the fan of 19th Century fiscal policy and 18th Century social policy) and Stockwell Day (the fan of 1930s German policing policies and 45th century [BCE] scientific theories) will do will be testimony to the necessity of a more representative, democratic form of choosing governments in Canada. Because, once again, these fools do not represent the majority. "The People" (to use a democratic cliche) are smarter than that.