Just off the wires -- Pennsylvania Sen. Arlen Specter is switching to the Democratic Party and running for reelection in the Democratic primary in 2010.
Obviously, this is good news for Democrats nationally, and on two fronts: In the short term, it gives them one more Senate vote (more on that in a second) for major priorities. In the long term, it makes the Pennsylvania senate seat more likely to stay in Democratic hands after 2010 because fringe conservative Pat Toomey will be the likely Republican nominee, and he's a potentially unelectable nominee.
There's just one thing to note: Specter is making clear he's not going to be a reliable Democratic vote on some of the key issues. Here's an excerpt of his statement:
My change in party affiliation does not mean that I will be a party-line voter any more for the Democrats that I have been for the Republicans. Unlike Senator Jeffords' switch which changed party control, I will not be an automatic 60th vote for cloture. For example, my position on Employees Free Choice (Card Check) will not change.
So, this is great news, but there are still going to be real obstacles to a progressive agenda.
Let me just conclude on a personal note: I think I speak for myself and anyone who ever lived/grew up in Pennsylvania that it's really hard to believe this. Arlen Specter has been an awful Republican senator for as long as I can remember. Since I was a kid growing up outside of Philadelphia, he was a guy who always seemed to be on the political stage at all times, and most often seemed to be doing bad things. The best you could say about him was that he wasn't as bad as his heinously awful Republican colleagues - but that's not saying much.
The idea of Specter running in a Democratic primary is really crazy - and I'm hopeful it will be a contested primary. State/local Democrats shouldn't simply defer to this guy, who Pennsylvania's rank-and-file Democratic voters/activists have been trying to dislodge for years (and rightly so). Even as we applaud Specter for switching parties, we shouldn't simply concede the primary. Indeed, there needs to be a contested and vigorous primary, especially since Specter's EFCA announcement means he will need pressure on his left, and especially since the primary winner in the increasingly blue state of Pennsylvania has a great shot of defeating someone like Toomey.
UPDATE: I should also note some simple, self-evident electoral truths: I know Rendell, the Pennsylvania Democratic Party, the DSCC and President Obama will all back Specter in the Democratic primary - that's what Establishments do: they cut deals with insiders and try to run over voters. However, even with Specter having that institutional support, it's hard for me to believe that a vigorous - and potentially successful - primary challenge couldn't be mounted. 2010 will likely be a low-turnout mid-term primary, meaning the harder core of the Democratic base vote will be pivotal in that primary. Those are voters who have been voting against Arlen Specter their whole lives - and who are just about the least likely of voters to suddenly vote for him because a bunch of big-name Democratic politicians in Washington say they should.