Does it matter what a presidential candidate thinks about evolution? Richard Dawkins thinks it does. Blogging for the Washington Post , he writes:
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.
On this view, the main problem with Governor Rick Perry's apparent view that Darwinian evolution is "just a theory" is that it reveals that he has not troubled to acquaint himself with the evidence -- evidence that (as Dawkins can, of course, demonstrate in his sleep) is sufficiently overwhelming to amount to "fact". If he is ignorant about evolution, he must either be stupid or else willfully blind. Either way, it doesn't bode well for a holder of the foremost elective office in the world.
Perry isn't the first to be called out for his apparent doubts about evolutionary theory. During her vice-presidential run back in 2008, Sarah Palin was accused (on somewhat ambiguous grounds) of holding creationist opinions. The current Tea Party darling Michele Bachmann has been much more specific than either Palin or Perry, telling reporters  in New Orleans: "I support intelligent design," before falling back on the default position among US religious conservatives that evolution was a subject of scientific debate and that schools should teach both sides of the "argument".
As she put it, "I don't think it's a good idea for government to come down on one side of a scientific issue or another, when there is reasonable doubt on both sides."
Of course, there is a debate about evolution. It's not a debate within science about whether or not evolution by natural selection is an established fact. There is no "reasonable doubt" in this sense. It's an argument taking place largely outside science as to whether or not evolution can be a legitimate subject for debate. And this raises a delicate problem for politicians whose ambitions depend upon appealing to a religious base whose opposition to Darwinism is more cultural than scientific. It has become a touchstone issue, "a question every presidential candidate must dread" , certainly every Republican candidate.
A bald statement of scientific consensus, of the type Dawkins seemingly requires of Perry, Bachmann and the others, would be a political risk and an act of courage that it is perhaps unreasonable to expect of most modern politicians. At the same time, any candidate who made a clear commitment to full-blown creationism would find it difficult to broaden their appeal beyond the religious right -- a body of opinion that, while powerful, is not electorally decisive. It's a subtle balancing-act, albeit one that makes little sense outside the very particular atmosphere of US politics.
Americans will be electing a president, not a professor of biology. It is indeed distressing to think that the "most powerful person in the world" (is that still true -- and, if so, for how much longer?) has an incomplete knowledge of the natural sciences. However, is it necessarily an indication of low political or administrative capacity, as Dawkins argues? Probably not. It is quite possible to be highly competent and efficient in most areas of life while holding eccentric beliefs (see, for example, the 19th-century congressman Ignatius Donnelly , who combined far-sighted views about tax reform with wacky ideas about Atlantis and the authorship of Shakespeare).
More to the point, perhaps, a belief in creationism and/or intelligent design correlates strongly with conservative positions on a whole range of seemingly unconnected issues: abortion, guns, capital punishment, taxation, even environmental policy. Meanwhile, public endorsement of evolution is a reliable marker for "liberal" policy platforms on these and other subjects. Unlike evolution, these are matters for genuine political debate and disagreement. Quite how evolution should have come to occupy its current place on America's cultural faultline is a puzzle that has much to do with peculiarities of culture and sociology but almost nothing to do with science.