Virginia Postrel hits on something interesting in a New York Times article based on a paper by a group of Harvard economists. The paper is about religion in politics, but she draws two broader conclusions:
Yet abortion rates show no significant change with the party in office, while tax rates rise significantly under Democrats – the opposite of what the political rhetoric promises. This result suggests that politicians move away from the social center mostly to get votes (“strategic extremism”) and diverge from the economic center because they actually prefer those policies (“nonstrategic extremism”).
Since the success of extreme messages depends on keeping your supporters better informed than your opponents, the model suggests that changing news media could be as important as changing social groupings.
Sounds right to me. The second point is intriguing because it suggests that getting the “liberal media” out of its elite, coastal shell might actually hurt the cultural conservatives who complain about it.