The Republicans has devolved into a party of numbskulls. Bush Jr, Rush, Palin share in common a hostility towards science and scientists and a fear of reasoned debate and evidence (except evidence that supports preconceived notions). The party is increasingly comprised of small-minded unthinking cultural conservatives who are incurious about the world around them.
Now there will always be a large minority of Americans who think dinosaurs never existed and climate change is a fiction manufactured by a bunch of “scientists” and who will vote for these idiots, but over the long run the republicans are going nowhere, unless of course our system of public education completely breaks down.