Vote him out of office. D'oh! We just reelected him. Nevermind.
I myself voted against him, despite being sternly told here that we couldn't afford to jeopardize control of the Senate. I wasn't expecting to be vindicated this soon.
We were vindicated before the election, in the general primary. Specter said in his debate, he would see to it that "centrist" judges were appointed, and he had his name on campaign signs with Kerry(i.e. Kerry/Specter) signs.