Specter’s defection is solely due to his abysmal poll numbers against the Republican primary challenger who almost beat him in 2004. That, the ongoing shift of PA voters from (R) to (D), and his total lack of principle makes this an easy choice for him.

He will now be feted by the Dems and the press and, more importantly, supported by them in the upcoming 2010 election. The seat will be hotly contested: the Dems will want to keep their 60 seats, and he will have a strong challenger, an age disadvantage, and a large number of pissed off republicans who will turn out to vote in an off year just to boot his Scottish-Law loving butt out of office.