[Repost to correct error in title.] I see most mainstream politicians and are not that radically different. They accept a bipartisan consensus of the government managing things, taking responsibility for the economy, and gov't spending remaining a big fraction of GDP. So when I read about a bitter partisan divide, I'm baffled. I just don't get why anyone is so fired up. This article in the NYT says it's because of levels of authoritarianism. I'm not of this answer, but it's better than any others I've heard. If I'm right, politicians are convincing people to hat one another over minor personality differences. The article quotes a paper titled Idealogues Without Issues. I love that title. "The three authors use a long-established authoritarian scale — based on four survey questions about which childhood traits parents would like to see in their offspring — that asks voters to choose between independence or respect for their elders; curiosity or good manners; self-reliance or obedience; and being considerate or well-behaved. Those respondents who choose respect for elders, good manners, obedience and being well-behaved are rated more authoritarian. "The power behind the labels “liberal” and “conservative” to predict strong preferences for the ideological in-group is based largely in the social identification with those groups, not in the organization of attitudes associated with the labels. That is, even when we are discussing ideology — a presumably issue-based concept — we are not entirely discussing issues. "Identity-based ideology can drive affective ideological polarization even when individuals are naïve about policy. The passion and prejudice with which we approach politics is driven not only by what we think, but also powerfully by who we think we are." Affective means emotionally driven. I had to look it up.