Hat tip to Ramesh Ponnuru for a link to this:

[T]he exurbs are becoming so reliably Republican that, just as in the black precincts of Newark, the tedious process of research and sophisticated targeting is becoming unnecessary. Turning out Republicans is becoming much more simple. The larger implication is that one of the most dominant demographic trends in America is the self-segregation of Democrats and Republicans. That may be good for the flushers in both parties, but it’s bad for the country.