The one Democrat whose strings may be cut is Arlen Specter, who was the 3rd-most-liberal Republican, but who immediately changed his voting pattern and is now a mainstream Democrat, the 30th most conservative in that party. If Specter loses his primary and becomes a lame duck, perhaps he'll decide to vote his conscience for the rest of the year -- except I'd expect it to take several months for him to locate that particular long-lost organ.On reflection, I expect Specter to still be more resentful of the Toomey right than liberals who delivered the final blow, and to continue voting as a mainstream Democrat as a lame duck. In fact, if he doesn't change, that's a gain for the Dems -- because if he was now the nominee opposing the very conservative Toomey, Specter would certainly have shifted to the right for the remainder of the session. On the other hand, I would also expect Specter to indulge in one or more "not proven" moment, and it's possible that one of those will be a key vote for the GOP on some issue.
Odds are that Blanche Lincoln will soon have her strings cut, but I think it's far less likely that she would react to primary defeat by voting to punish the liberals who will have defeated her. Lincoln will be 50 in January 2011; unlike Bennett, Specter, and (if he loses) McCain, she'll be looking for a job, and I'd expect that to replace the electoral incentive in influencing her votes on the Senate floor. I don't see her cut out for a Zell Miller role on Fox News, although I'm sure that's available for her if she wants it; I think it's much more likely she would spend the time auditioning for a role (Ag Secretary? Chicken industry czar?) in the Obama administration -- also something presumably available to her if she wants it. Indeed, as with Specter, she could have been counted on to shift right after being nominated; if she is defeated and no longer has to worry about an Arkansas electorate, she might drift left a bit for the rest of the year.