Grandstanding

Arlen Specter is a threatened incumbent. He wants to keep his job in the US Senate, but he faces challenges from the left and the right. A threatened politician is an unpredictable one. Thus you have him trying to make hay out of Eric Holder's confirmation hearings for Attorney General and his role in the Marc Rich pardon. Nobody much likes the Marc Rich pardon, so Specter probably thinks he gets plaudits from the right for challenging their favorite subject, Bill Clinton (this time by proxy), as well as not much heat from the left. It's ridiculous for Specter to say "questions must be addressed" when he can ask Holder personally, but what he wants is a big buildup to a contentious confirmation hearing where he can rail at the nominee and look all Senatorial. Patrick Leahy is having none of it but I expect that Specter will probably get his wish, or at the very least, if he hasn't delayed the hearings, he's raised the anticipation for them.

Because Specter will be primaried, he will be unpredictable and unreliable throughout the 111th Congress. He's no "moderate" to count on for anything.