In the end, it's not up to us. It's up to the other 54 pubbies, many of whom are not weenies: Inhofe, Kyl, Frist, etc. They shouldn't make a deal with Specter that requires them to "trust" him. They just make a deal with him that he can keep the chairmanship as long as he puts each and every nominee through the committee and onto the floor, and then he--Specter--will oppose the filibusters. If on the final vote Specter opposes the nominee--well, a promise to support each and every nominee in advance is something a Senator can't give. But they should agree in advance with Specter that if he joins the filibuster it costs him his chairmanship.
I'm sorry, but given Arlen Spector's Senate record and his comment/gaffe about judges, he doesn't deserve the privledge of chairing the judiciary.... No matter how you slice it, he doesn't deserve that honorable and most trusted, powerful job.