Reading on, we find that the only other declared candidates are Republican Pat Toomey and Democrat Joe Torsella. Cillizza strongly suggests that Specter considers himself vulnerable in the GOP primary, and thus sees much brighter prospects in the general election if he can get the Dem nomination.
Pennsylvania Sen. Arlen Specter will switch his party affiliation from Republican to Democrat and announced today that he will run in 2010 as a Democrat, according to a statement he released this morning.
Specter's decision would give Democrats a 60 seat filibuster proof majority in the Senate assuming Democrat Al Franken is eventually sworn in as the next Senator from Minnesota. (Former Sen. Norm Coleman is appealing Franken's victory in the state Supreme Court.)
"I have decided to run for re-election in 2010 in the Democratic primary," said Specter in a statement. "I am ready, willing and anxious to take on all comers and have my candidacy for re-election determined in a general election."
Of course, he won't admit that publicly. Rather, we get the usual boilerplate "GOP has abandoned the big tent, the conservative extremists are in control, yada yada yada."
Many consider Democrat control of Congress to be a fact of life in the coming years, and Specter wants to be a part of the winning team. He'll even be invited to Democrat cocktail parties for a while, at least until the propaganda value of his switch runs its course.