It seems to me that David Frum’s argument here shouldn’t be with conservatives. He’s really arguing with the idea of political parties, or at least parties that have sorted ideologically. I’ll be the first to admit that Mike Castle was a better fit for Delaware’s voters than Christine O’Donnell. But let’s face it: many more Republicans broadly share O’Donnell’s views than Castle’s, even in Delaware. Even in states where a large number of GOP elected officials are moderate or liberal, liberal Republicans are not very thick on the ground.

Moreover, independents have played a very big role in this ideological sorting. It was they who elected the Democrats in 2006 and 2008, bouncing many a moderate Republican from office in the process. And they just elected the Republicans this year, bringing in a more conservative Congress and jettisoning many moderate Democrats. Swing voters did not spare Lincoln Chafee or Gene Taylor (or even Chet Edwards, who is actually a centrist).

If small groups of voters are “hijacking” the two parties, it is largely because they are the ones who actually care about what is going on in politics. The moderates largely tune out. If the great American center has been disenfranchised, let’s not ignore the fact that they were complicit in their own disenfranchisement.