As a life long resident of Pennsylvania, I can honestly say if McCain picks former Pa Gov. Tom Ridge (the quitter) as his running mate in the hopes of picking up Pennsylvania votes in an effort to swing Pennsylvania into the Red, in my case it will have quite the opposite effect.
Tom Ridge (the quitter) is a Republican in party affiliation only. Tom Ridge is, in my opinion, nothing but another Clinton with a Hearing Aid. A Wolf in Sheeps clothing.
Hopefully, he won't have a chance to do to the rest of the Country that he has done for (or to) Pennsylvania. Tom Ridge was in way over his head as the first Secretary of Homeland Security, and Tom Ridge quit that position.
I can in no way picture Tom Ridge (the quitter) as a "Heartbeat away from the Presidency".
If McCain wants to pick someone with Tom Ridge's qualifications, he could offer the second slot to a known Liberal instead of Tom Ridge.
At least that way, you'll know what you're getting.