I've been thinking about Specter for awhile. I've decided that while we should make our opinions known, we should trust GWB. If Bush wants to keep him as chair, they may have come to a gentlman's agreement.
GWB is a very keen politician as he has shown us repeatedly. Ultimately we need to back off if GWB keeps him. I think that we could cause a unnecessary public rift between the moderates and the conservatives that will just delighten the press and make the conservatives seem too punitive to those who don't agree.
We should inform our senators of our displeasure, but ultimately GWB will do what he needs to do and call in his favors when he needs to.
Furthermore, having a "rebellious" Specter endorse Bush's court nominess might be the means by which W out-smarts the Leftists again.