Creationism and its thinly-disguised counterpart, Intelligent Design, uses a "wedge" argument that refers to creating a wedge of doubt in the scientific consensus that evolution is as proven a fact as any scientific theory can be proven. On the scientific level, they've gone nowhere - two of my linked blogs, Chris Mooney and Carl Zimmer, talk about this in detail, along with many other great science websites. Some religious conservatives who hate science have clutched to the idea, however.
I have an alternative suggestion, that the evolution "wedge" belongs to those of us who want significant change in the progressive direction for American society, a wedge in the sense that George Lakoff might use the term. Here's the argument: America is more conservative than other western nations in large part because of religious conservatives who believe in the literal truth of the Bible. Very few people on the progressive side of the spectrum have trouble with teaching evolution as a proven theory, but the conservative side is strongly split on the issue. To the extent we emphasize the evolution in debates against creationists, conservatives become split and progressives unite. To the extent that evolution wins that debate, which is pretty obvious that it does, then people cannot remain Biblical literalists. The evolution wedge opens people up to other ways of thinking, say regarding homosexual rights, that they might otherwise have ignored.
I'm not saying that being religious is wrong or inherently conservative, just that Biblical literalism tends to support conservative ideas. Evolution can open things up.
So what to do with this? I think movement conservatives may care less about teaching Intelligent Design in schools and more about minimizing ANY discussion of evolution in schools, for the exact reasons I've mentioned. One response would be to advocate "teaching the controversy", to set evolution theory against the mush that is I.D. and show how fantastically much better evolution is in explaining the world. The problem is most evolution advocates oppose teaching the controversy, partly because there is no scientific reason to teach I.D., and partly because any mention of I.D. would get distorted by religious conservatives in politically-conservative school districts.
I disagree and think the benefits of greater exposure to evolution would outweigh the costs, but still I have an alternative suggestion: design school curricula that focus heavily on evolution in ways that answer the bogus challenges from creationists, without ever using the words "Intelligent Design" or creationism. The curriculum could answer questions like "are there transitional fossils between different species" with perfect examples of transitional fossils, or explain why evolution is NOT like a tornado passing through a junkyard and assembling an airplane, without talking about the religious motivations that lie behind these questions. This curriculum could be waved in front of the face of anyone who says their concerns about evolution are not being addressed. I know, they'll have bogus responses, but I believe it can help a great deal to move the debate in the right direction, and open up the wedge that we need.
keywords: evolution, wedge, Lakoff, homosexuality