It's just getting to that
point where it getting (at least in the eyes of politician and their demographers) so polarized that neither side feels the need to reach out to the other. It's the 'mobilize the base' vs. 'build a broad consensus' school of thought.
Modern marketing really has gone a long way to dividing the country into 'special interest' segments. It's really bizarre.
I'm sure the Democrats are just as guilty. Hard to imagine John Kerry addressing an assembly of Southern Evangelicals.