That logic makes sense to me.
Also the Hotline poll out today (Cong. numbers even) saying gives a little more credence to the earlier Gallup assertion (which I have been assuming previous is just an outlier).
Did not see the PA-08 debate, but I take your word on it.
The thing with Santorum-Casey that is kinda unknown is how Casey will play once he gets in debates. According to most polls, there are still roughly 20%-25% of the voters who don't know him well enough to give an opinion of him and that may decide his (and Santorum's) fate.
I will admit that Santorum has been using his time and money effectively this summer, whereas Casey has not, and we're seeing the shift from this in the polls of late, imo. Still a high mountain for Santorum to climb, overall.
"Here’s my advice: Don’t get carried away. The changes in both races are, so far, superficial. The fundamentals basically remain unchanged."