The obvious rejoinder to Mike's post is that when people cluster in "communities of sameness, among people with similar ways of life, beliefs and in the end, politics," they also cluster among people of the same race and socioeconomic status.
The impulse to seek out those similar to oneself isn't new, but today's society offers people many more methods by which to act on it. Marketers know this. Chris Anderson writes in his book The Long Tail, "If the twentieth-century entertainment industry was about hits, the twenty-first will be equally about niches." Successful companies are producing less of more, that is, to appeal to the clustered masses.
Some will say the drawbacks of racially or socioeconomically homogenous classrooms, classrooms that Mike rightly calls undesirable, far outweigh the benefits of schools where pupils parents agree on "what good education looks like." Maybe. But as long as adults like to send their kids to close-to-home schools (they do), and as long as they live near others like them (they do), individual schools will be racially and socioeconomically uniform.
The Thernstroms (among others) convincingly document that this isn't as bad as it seems. The alternatives, which all depend on busing, are far worse, in no small part because they shift schools' focuses away from learning. Clustered schools, by contrast, could focus even more attention on learning. Mike writes, "As geographic sorting occurs, neighborhood public schools will have the same ability to customize themselves to fit the values...