Believe me, I understand, though I personally was not surprised Santorum backed Specter. You could look at it as being a "party whore"; I won't argue. I saw it -- and I believe Santorum did -- as attempting to keep a key seat in Republican hands to stop a Democratic takeover of the entire chamber.
The RNC knew full well that was a danger. The last, last thing we want is for Bush to be stuck with a Democratic Senate, as Daschle's 2001 coup should remind us. Santorum played politics, as politicians will do; I sincerely doubt that Toomey himself would not have done the same thing in that position.
-Dan