I found The Righteous Mind: Why Good People Are Divided by Politics and Religion to be a most interesting, learned discussion of how people of different political persuasions have very different ways of thinking about what’s right or wrong. The author has developed (and tested) a theory of how people rely on a small number of values that govern their moral choices at a very primitive level. Different values, different choices, and we know that instantaneous, emotional choices (see Thinking, Fast and Slow) often prevail, and that we will make up logical explanations to match them, after the fact. So if your main value is Care, you will likely vote Democrat, but if you think Loyalty and Authority are more important, you will just as likely vote Republican.
I did have a couple of concerns about the book. One was that the theory seems to be overly focused on the American political system and it’s not clear that it would apply well for other systems. The other is that the author had no recommendations for how to make things better, save the obvious “try to see the other person’s side”. Great advice, but surely if it were that easy some of our politicians may have tried it already?