I more or less agree with Maher's assessment, but I think there has been a growing tide of anti-intellectualism and fear-based politics over the past several years. The tea party over the past year has given voice and increased credibility to these loons and has pulled some otherwise sane people to the dark side. So, I htink the Tea Party overall has changed the political landscape.
For a lot of people its not really about policy, its about us vs them. Whatever the other guy's policy is, ours is the opposite - and the more opposite the better. And we'll do and say anything we need to win. Its like US national politics has become the Lakers/Celtics rivalry (or UNC/Dook, or Yankees/Mets, etc...). Its not about policy, its about scoring points.