The best thing I've read about political differences is the book Predisposed http://www.amazon.com/Predisposed-Liberals-Conservatives-Pol...
It makes the argument (supported by copious research) that there are biological correlations of conservatism and liberalism with disgust reflex, taste in food and art, perceptual cues and threat response. I'm not convinced that they have the direction of causation settled but it is interesting research. Conservatives and Liberals literally see the world differently. No surprise that logic doesn't work to help either side sway the other.