“As people seek out the social settings they prefer–as they choose the group that makes them feel the most comfortable–the nation grows more politically segregated–and the benefits that ought to come with having a variety of opinions is lost to the righteousness that is the special entitlement of homogeneous groups. 

We all live with the results:  balkanized communities whose inhabitants find other Americans to be culturally incomprehensible; a growing intolerance for political differences that has made national consensus impossible; and politics so polarized that Congress is stymied and elections are no longer just contests over policies, but bitter choices between ways of life.”  Bill Bishop from The Big Sort