Let me make myself clear. I do not, of course, think that most Americans or Spaniards are ignorant. Ignorant means willfully stupid. Most people are not very well-informed. There's a difference. And when I say "not very well-informed", I'm referring to the half of sentient beings who are exposed only to media crap and word-of-mouth. The other half gets at least some information that isn't crap.
I think Bush won the election for the following reasons.
1) Most Americans think that the country has made progress since 2000, despite our being at war since September 11, 2001. There hasn't been another terrorist attack on US territory since, and the economy is chugging along quite well. Most Americans feel pretty prosperous and reasonably secure. Since Bush has been the president for those four years, let's re-elect him.
2) Most Americans are in favor of United States policy on terrorism and on Iraq. They see Al Qaeda and the Taliban and Saddam and all the other Islamic terrorist groups and regimes as somehow being connected and as the enemy. They believe we should defeat the enemy before we negotiate with him, since he declared war on us, not vice versa.
3) Most Americans feel closer to the moral and ethical values of the conservatives rather than those of the liberals. That's not saying that the ethics of liberals are somehow wrong or immoral; in probably 98% of cases they're the same. (I.e. both liberals and conservatives agree you shouldn't kill people or steal stuff or beat people up or rape them or rip them off or destroy stuff that doesn't belong to you or dump your garbage in the river or discriminate against people or generally act like a dick.)
Where liberals and conservatives disagree on social issues is on the smaller stuff--we all agree that unemployed single moms can't be left to starve in the street, we disagree on the methods the government should use to try to deal with the problem. We all agree the government should help disadvantaged people (kids from poor families, that is) to get a leg up, to get an education and some skills in order to have a decent, productive, generally happy and pleasant life. We disagree over what precisely the kids ought to study. We all believe gay people shouldn't be persecuted and should have the same rights as everyone else to live their own lives. What we're not all sure about is whether this includes the right to get married. We all agree that shooting heroin is bad for you and should be discouraged. We disagree on...but you get my point.
Right now most people tend to agree more with the conservatives on these issues.
So I suppose my point is that you don't have to be particularly well-informed, which most people in Spain and America aren't, to know where you stand on these issues. Another point is that being well-informed has nothing to do with being leftist or Democratic. Many, perhaps most, of the well-informed voted for Bush. A third point is that there's nothing wrong with being ill-informed. Most people have a job, a spouse, a kid, a dog, a house, some friends, some relatives, a hobby or particular interest, a favorite TV show, kind of music, and/or sports team, one vacation per year, probably some sort of religious belief, a set of ethical standards, a collection of experiences, and that more or less fills up their lives. That doesn't mean their lives are empty, far from it. It just means that politics and current events aren't one of the things that fills them.