It doesn’t matter if the seat is nominally “Republican” if the seat’s holder doesn’t vote that way when it counts.
I am mad at Specter too, and I want him out, but Specter, as bad as he is, would be better than someone like Murtha rising to the Senate!
Things can always, always, always get worse!
Also, it is longstanding policy that Republican officeholders from outside an area do NOT endorse challengers, in Primaries, likewise the Party should stay neutral, in Primaries.
The Republican Campaign Committee is NOT the Republican Party.