Just a quick data point. Sen. Arlen Specter (D-PA) fielded questions at a Netroots Nation panel this morning about whether he'd encourage his colleagues to support cloture on Democratic bills. Though he elided the specific question, he did say that, unless Democrats flew off the handle and began trying to limit the first amendment, or civil rights for gays, he will vote with the party to bring legislation to the floor for an up or down vote. Specifically, he said he'd support cloture on the Employee Free Choice Act, even if he disagrees with the underlying bill.

He's also recently assured labor organizers that they'd "like" how he votes on EFCA. Before he switched parties, and even for a while thereafter, he said exactly the opposite.

Late update: Specter also said that he never asked President Obama to clear the primary field for him.

Late late update: Here's video.