His "Red" & "Blue" labels come from the maps of Republican/Democrat counties in the 2000 election, but Brooks' study has little to do with politics. It is cultural, and it works on many levels.
And that's the way America is. We are not a divided nation. We are a cafeteria nation. We form cliques (call them communities, or market segments, or whatever), and when they get too big, we form subcliques. Some people even get together in churches that are "nondenominational" or in political groups that are "independent." These are cliques built around the supposed rejection of cliques.
We live our lives by migrating through the many different cliques associated with the activities we enjoy and the goals we have set for ourselves. Our freedom comes in the interstices; we can choose which set of standards to live by, and when.
We should remember that there is generally some distance between cliques�a buffer zone that separates one set of aspirations from another. People who are happy within their cliques feel no great compulsion to go out and reform other cliques. The jocks don't try to change the nerds. David Rawley, the Greencastle minister who felt he was clinging to a rock, has been to New York City only once in his life. "I was happy to get back home," he told me. "It's a planet I'm a little scared of. I have no desire to go back."
What unites the two Americas, then, is our mutual commitment to this way of life�to the idea that a person is not bound by his class, or by the religion of his fathers, but is free to build a plurality of connections for himself. We are participants in the same striving process, the same experimental journey. (One America, Two America..., via Reductio Ad Absurdum)