In recent days, Republican candidates Rick Perry and Jon Huntsman have both had occasion to share their views on evolution (Perry says no, Huntsman says yes). The National Journal's Ron Brownstein suggests that this might help Huntsman a bit to make his case to "the overlapping circles of the party's best-educated, least religiously devout, and moderate elements." Good luck with that, governor.
It isn't that there aren't educated Republicans who understand evolution, and it isn't even that they're a minority within their party -- although they are (according to Gallup, 52 percent of Republicans think God created humans in our present form less than 10,000 years ago). It's that none of those people care enough to argue about it. They've ceded this issue to the crazies. When somebody tries to get their local schools to teach the fraud of "intelligent design," you aren't going to find elite Republicans complaining about it. They'll shake their heads and go back to writing white papers on the salutary effects of cuts in the top tax rate.
As you may know, fewer Americans understand and acknowledge evolution than citizens of any other developed country. Here's an international comparison -- it's a few years old, but there isn't much reason to think things have changed:
Much of the explanation lies in the U.S.'s unusually high levels of religiosity compared to other Western countries, but politics plays a role, too. One of our two major political parties regularly politicizes even the most settled scientific questions. If a new Democratic plan for health care relied on the Pythagorean Theorem for some reason, Republican leaders would immediately begin saying that it's just a theory, and lots of scienticians don't think it's true. It'd echo through Fox News and conservative talk radio, and before you knew it, partisans would decide that to be a true conservative means questioning the Pythagorean Theorem. So yes, evolution challenges some religious beliefs, but most religions, including Catholicism, have found a way to reconcile their beliefs with the factual evidence. What's different in America is that we have institutions that sustain and encourage disbelief in that evidence.