… an online poll that showed the vast majority of the group’s roughly 170,000 members in Pennsylvania – 85 percent – would consider supporting a Democratic challenger against Specter.

First, on-line polls are not considered accurate – self-selecting responders. Second, MoveOn’s membership is exceedingly and most likely not representative of the Democratic party in Pennsylvania. Anyone as politically savvy as Sen. Specter will take this with an ample “grain of salt”.