Take a look at my state. Our two senators are Bob Casey, Jr., a Democrat who happens to be anti-abortion (do you believe that a staunchly pro-choice Republican could win a Republican primary now?), and Arlen Specter, a Democrat who until recently was a Republican because there’s no longer any chance of a pragmatic centrist winning a Republican primary. I seriously doubt that Tom Ridge, a centrist on many economic issues who also happens to be pro-choice, could get elected Governor again today. Strike that — he could get elected Governor today if he ran as a Democrat, but I really don’t believe that he could get the Republican Party’s nomination these days. That’s the difference between the Democratic and Republican parties at the national level these days: people like me may disagree vehemently with the Democrats who voted against the health care bill and call them all sorts of rude names, but we aren’t trying to run them out of the party.

In the long term, it doesn’t do this country any good if the Republican Party implodes in a repeat of the Whig Party’s devolution into the Know-Nothings, but it looks an awful lot like that’s what might be happening. We don’t have a parliamentary system here, where there are multiple parties that come together to build governing and opposition coalitions following each election. Instead, diverse interest groups form their governing coalitions under the umbrella of the two major parties here. Those coalitions aren’t perfectly coordinated, nor should they be. When one of those two parties becomes dominated by people who have no interest in coalition-building, it means that this country’s likely in for an extended period of single-party rule. That can’t be healthy.