In the last few weeks, and at tonight’s Republican debate, lots of national politicians have been asked their views on evolution, and lots of politicians have answered embarrassingly. We should bear in mind, as I pointed out before:Like the Miss USA contestants, most politicians (excluding those on local school boards or state boards of education) will have little opportunity to influence how evolution is taught. In answering questions about evolution during campaigns, their goal is rarely to indicate a clear conception of how science works and why evolution is central to modern biology. Instead, they must alienate as few constituents as possible, keep their base happy, and avoid an embarrassing misstep that could draw harmful national mockery. Because of the widespread perception that human evolution carries implications for the nature of morality, the soul, and other central aspects of personal identity and ethics, candidates tend to skirt the issue. They often call for equal time for evolution and creationism and then rapidly transition to the importance of religion in their personal lives.And lo and behold, tonight we had Rick Santorum commenting about evolution: “Absolutely not. I don’t believe it,” continuing “For evolution to explain the creation of the human species from nothing to human beings, absolutely not I don’t believe in that.” A couple weeks ago, Rick Perry replied (falsely) to a 9 year-old’s question about evolution by saying:How old do I think the earth is? You know what? I don’t have any idea. I know it’s pretty old, so it goes back a long, long way. I’m not sure anybody actually knows completely and absolutely how long, how old the earth is. I hear your mom was asking about evolution. You know, it’s a theory that’s out there. It’s got some gaps in it, but in Texas we teach both creationism and evolution in our public schools, because I figured you’re smart enough to figure out which one is right.Pretty much as I predicted (though note that Jon Huntsman has managed to actually endorse science as science). But why should we even care what politicians think about evolution, given that none of these candidates would, should they manage to win the presidency, be able to influence how evolution is taught? In part, the issue is the President’s bully pulpit. Anti-evolution comments by Reagan and George W. Bush both inspired creationist activism at the local level, making life harder for students and teachers. Far more important is that evolution is a shibboleth for a candidate’s general attitude towards evidence and ideology. The only basis for rejecting evolution is religious (and political) ideology, and it’s worth knowing whether a candidate is willing to toss out science and scientific testing for the sake of ideology. No question that it’s important to consider a candidate’s values, but people who don’t value evidence or expertise should not be in charge of important decisions. I have no trouble drawing a line between George W. Bush’s off-handed rejection of the evidence supporting evolution – and the expertise of scientists who tried to explain that evidence to him – and his dismissal of expert testimony and extensive evidence that Iraq did not, in 2003, possess WMDs or active WMD programs. Indeed, name any other policy failure of the Bush years, and a similar prioritizing of ideology over evidence becomes clear. Precisely because evolution is so distant from presidential policy, it makes a useful way to evaluate a candidate’s openness to evidence, to scientific expertise (or professional expertise in general), and to empirical testing more broadly. The other major topic of science denial at hand – climate change – is trickier precisely because rejection of the science is often a simple way to attack particular policies tied to climate change. Nonetheless, the way Rick Perry fumbled a question on climate change in tonight’s debate is informative. Perry was asked to justify his insistence (which Politifact continues to ding as “false”) that growing numbers of scientists reject climate science: I do agree that there is…the science is not settled on this. The idea that we would put Americans’ economy at jeopardy based on scientific theory that’s not settled yet, to me is just nonsense. I tell somebody: “Just because you have a group of scientists that stood up and said, this is the fact” … Galileo got outvoted for a spell. But the fact is, to put America’s economic future in jeopardy, asking us to cut back in areas that would have monstrous economic impact on this country, is not good economics, and I will suggest to you is not necessarily good science. Find out what the science truly is before you put the American economy in jeopardy.Pressed on what scientists he’s found compelling on this issue, Perry dodged and dismissed the idea of listening to “some scientist somewhere.” His opening passage, like his comments on evolution, seem to forthrightly endorse the legitimacy of letting religious and political authority suppress (“outvote,” in his words) scientific results. By the time Galileo was publishing on heliocentrism, the idea was already circulating and widely accepted in scientific circles, including Jesuits. He wasn’t outvoted by scientists, he was outvoted by the political and religious leadership of his country. If that’s what Perry is endorsing, then it’s a deeply troubling sign. More likely, he’s just flaunting his ignorance. Just as when he (or others) endorse balancing evolution and creationism, he’s setting forward the principle that we should ignore what experts tell us, ignore the accumulated evidence of a century or more of research, and let that ignorance drive policy. These candidates’ answers don’t matter so much because of the particulars of the science they reject: they’ll have advisors who can give them facts. These answers matter because they tell us whether these candidates, once in office, would even bother asking for the evidence, would care what the facts even are.