Current Politics dominated by ignorance?

More of the same bigoted language from McCain supporters. This time from the predominantly white people from the town of Potts ville, Pennsylvania, where McCain supporters could be seen yelling, "Bomb Obama!"

How did politics in the US come to be dominated by people who make a virtue out of ignorance? Was it charity that has permitted mankind’s closest living relative to spend two terms as president? How did Sarah Palin, Dan Quayle and other such gibbering numbskulls get to where they are? How could Republican rallies in 2008 be drowned out by screaming ignoramuses insisting that Barack Obama is a Muslim and a terrorist?
On one level this is easy to answer. Ignorant politicians are elected by ignorant people. US education, like the US health system, is notorious for its failures. In the most powerful nation on earth, one adult in five believes the sun revolves around the earth; only 26% accept that evolution takes place by means of natural selection; two-thirds of young adults are unable to find Iraq on a map; two-thirds of US voters cannot name the three branches of government; the maths skills of 15 year-olds in the US are ranked 24th out of the 29 countries of the OECD.

But this merely extends the mystery: how did so many US citizens become so dumb, and so suspicious of intelligence? Susan Jacoby’s book The Age of American Unreason provides the fullest explanation I have read so far. She shows that the degradation of US politics results from a series of interlocking tragedies.