Over the last few decades, an experiment has been taking place within the Republican Party. It has been conducted not by party leaders as much as by the rank and file or so-called base. It has been an experiment as to whether a politically pure party can be a viable party. To my knowledge this has never been done before.
Over the years, groups such as Club for Growth have sought out those who were considered apostates and targeted them for inter-party challenges. In many cases they have picked off those moderates and have made the party more pure.
These groups tend to be inward looking and wary of the outside world. For them, the reason the GOP last in 2006 and 2008 was because they were not pure enough. George Bush? He spent like a drunken sailor. John McCain? He was too feckless. No, there is no need to change and to expand the coalition, there is only the need to be more faithful and more pure and purge those who don't agree.
Ross Douthat, in his debut column for the New York Times, argues that maybe Dick Cheney should have run for President last year, so that the purists would have their way- and when they lost, no longer have the excuse that they were not pure enough in their ideology.
Arlen Specter's decision to leave the GOP for the Democrats might have many conservative purists shouting Hallelujah today. But it means that they probably have resigned the GOP to a rump status, but hey, at least they are a bit pure than they were before.
Will being pure be the winning strategy for the GOP? I'm gonna say this: you can be an ideologically pure party or you can be a majority party, but you can't be both.