The problem of polarization continues and is likely to be the defining political characteristic of contemporary United States. The US populace has been polarized before but it is typically over a single issue. Slavery, for example, in the 19th century. Below is some data from the Pew Foundation on the increasing tendency toward rigid opinions and polarized values.

As the Pew report concluded, the fault is structural; it is not the sort of problem that can be solved by an individual or piece of legislation. Political parties are more ideologically coherent than they’ve been probably at any time since the Civil War. As citizens spend more time talking to those who are like them – which is intensified in the current social media environment – they become more easily reinforced for their particular perspective. The literature by Sunstein and others conclude that this mediated world of interaction with others who hold the same opinion as you do causes those opinions to become rigid and increasingly unmovable. And the dynamic of polarization is increasing. But with the realignment of ideologies that started over the issue of civil rights in the 20th century, ideological purity became a bigger factor in American elections.

Ideological purity is a dangerous form of essentialism. One’s beliefs become so strong, and the sense of ingroup and outgroup become so clarified, that perceptions of the outgroup are assumed to be biologically natural.

The Table above shows that from 1994 to 2014 a larger percent of Republicans became consistently conservative. And a larger percent of Democrats were consistently liberal. The two groups – liberals and conservatives – consistently drifted toward more rigid ideological opinions that do not vary and are less subject to moderation and persuasive influences.

The data reflected in the bar graph above shows that the two parties have increasingly unfavorable attitudes about the other. From 1994 to 2014 the unfavorable attitudes about the other party has more than doubled. I don’t need to reiterate the danger of these data. They make working together and solving problems in any sort of bipartisan way almost impossible.