A new story from the Politico accurately points out that the currently announced Republican retirements will push the party towards the right. However, it provides a platform for former Rep. Sherwood Boehlert to claim "You’ve got the Club for Growth, you’ve got MoveOn.org. What does that produce? Not much." In other words, the House is becoming more polarized between liberal Democrats and conservative Republicans, leading to stalemate.
Is Boehlert correct? Are MoveOn and the Club for Growth equally responsible for producing a Congress that can't get anything done?
My impression is that this is inaccurate but an easy frame for the media to adopt-- the "pox on both houses" argument that allows blame to descend on both parties. But I turned to one of my favorite websites, www.Voteview.com, to find some data to back up my suspicions.
Using roll call data through July, this page ranks the 110th House using a scale which emphasizes ideological polarization (by its reckoning, Pete Stark of California and Jim McDermott are the most liberal; Jeff Flake of Arizona and Ron Paul of Texas are the most conservative), giving each member a rank. A look at the Democratic members as a whole vs. Republican members as a whole gives Democrats an average rank of 117 and Republicans an average rank of 334. (The dividing line between the two parties is 233.5.)
Looking at the new Democrats as a whole, we find that their average rank is 155.7-- 40 points more conservative than the party as a whole. Looking at the new Republicans, their average rank is 383-- 50 points more conservative than the rest of the party. (The Politico article points out that 12 of the 15 Republican freshmen joined the conservative Republican Study Committee.)
The argument that the House isn't producing legislation that the Senate can't support because it's monopolized by liberal Democrats doesn't hold up. (Keep in mind, also, that these new Democrats represent a much larger percentage of the caucus because the Republicans had so few incoming members.) Indeed, Pelosi's incentives to craft legislation that tends towards Republican policy preferences in order to keep the most conservative Democrats happy are greater than the incentives of Hastert and DeLay in the previous Congress to keep moderates satisfied.
A useful exercise, if someone feels so inclined, would be to compare all the new representatives with the members they replaced-- whether by defeating incumbents or winning an open seat-- to determine whether the ideological shift is as small as this analysis suggests.