Why is ignorance of evolution a litmus test for politicians?

I know this is already done to death around the internet but it is so well expressed and so succinctly that I must re-post it here because it reflects my own opinion and disgust at voters who empower such politicians:

A politician’s attitude to evolution is perhaps not directly important in itself. It can have unfortunate consequences on education and science policy but, compared to Perry’s and the Tea Party’s pronouncements on other topics such as economics, taxation, history and sexual politics, their ignorance of evolutionary science might be overlooked. Except that a politician’s attitude to evolution, however peripheral it might seem, is a surprisingly apposite litmus test of more general inadequacy. This is because unlike, say, string theory where scientific opinion is genuinely divided, there is about the fact of evolution no doubt at all. Evolution is a fact, as securely established as any in science, and he who denies it betrays woeful ignorance and lack of education, which likely extends to other fields as well. Evolution is not some recondite backwater of science, ignorance of which would be pardonable. It is the stunningly simple but elegant explanation of our very existence and the existence of every living creature on the planet. Thanks to Darwin, we now understand why we are here and why we are the way we are. You cannot be ignorant of evolution and be a cultivated and adequate citizen of today.

Just so.

The author, Richard Dawkins, has expressed it bluntly in this article: there is no excuse except pandering to the stupid for such willful ignorance to be held by anyone with a reasonable grasp of reality and the ability to learn. There is certainly no reason except stupidity to reward such idiots in politics. Those who do reward it with their vote need to be opposed in very blunt terms: they are exercising idiocy – or, in Discovery Institute wedge issue terminology about Intelligent Design, IDiocy. Voting for a creationist who denies the fact of evolution is an idiotic act that attempts to empower ignorance of those who hold a belief contrary to what is true in reality into positions of authority over all us in the public domain. Stupid is as stupid does. That’s what voting for a anti-evolutionist means: an exercise in stupidity.

(h/t pharyngula)