Will the last moderate Republican to leave please turn off the lights?

Today's big news is that moderate Pennsylvania Senator Arlen Specter has switched parties, and will now caucus with the Democrats. Now some of this is pure political self-interest. He barely survived a primary challenge by conservative Pat Toomey in 2004, eking out a 51%-49% victory. Toomey looks set to challenge Specter from the right again in 2010, and a recent poll showed Toomey routing Specter 51% - 30%. Specter knows he would lose a Republican primary, particularly with many moderate Republicans having become Democrats in this swing state in past few years (Thanks, Bush/Cheney). His only chance was to run as a Democrat.

But this is about more than Specter's own political ambition. The Republican party has a huge problem right now. Their tilt to the right in the past decade - socially, religiously, and economically - have marginalized them and made them a regional party, based in the deep south. In recent elections, they have seen the Democratic party take every New England Congressional seat, expand into the growing southwest, take the industrial midwest, consolidate the coasts, turn Virginia into a blue state, and even capture states like Indiana and North Carolina in the 2008 Presidential race. As Specter himself noted "As the Republican Party has moved farther and farther to the right, I have found myself increasingly at odds with the Republican philosophy and more in line with the philosophy of the Democratic Party."

Specter was one of only three real "moderate" Republican Senators, and even that was somewhat debatable. And you have to assume that Maine won't be electing many Republicans to the U.S. Senate once Collins and Snowe eventually leave the institution. Basically, the Republicans have lost the middle. Voters in swing districts saw the GOP's move to the far right and elected Democrats to replace them in 2006 and 2008, leaving generally only those Republicans in safe seats in very conservative districts. Their national face is now people like Dick Cheney, Rush Limbaugh, Michele Bachmann, Sarah Palin, Glenn Beck, Newt Gingrich and Michael Steele. That's not a way to appeal to moderates or expand the party's ever shrinking base. Nor is picking off your few remaining moderates, like Specter, with primary challenges from the right.