Rick Santorum's book tour was designed, no doubt, to boost the Senator's popularity -- both nationally and in PA -- though there were news reports that some Santorum advisors thought even publishing this book was a crazy idea, much less promoting it as aggressively as Santorum has.

It's possible those Santorum aides were right.

SurveyUSA interviews 600 adults in each state every month and asks each person whether they approve or disapprove of the job their United States Senator is doing.

Coming in dead last this month among the nation's 100 Senators was -- you guessed it -- Rick Santorum.

The survey was released Friday morning, and it shows Rick with a -4 net job approval rating, with 46% disapproving of the job he's doing and 42% approving.

Before he started showing up on every news-talk show that would allow him a few minutes to promote "It Takes A Family," Santorum's approval rating had been relatively steady -- coming in at 44% in May and at 45% in both June and July. Between July and August (coinciding with his book tour), the rating dropped 3 points, to 42%. But his disapproval rating has been climbing over the summer -- coming in at 38% in May and rising to 46% in August.

It's a net change of 10 points overall.

During his July 28 appearance on CNN's "Inside Politics," Rick's incredible bravado allowed him to claim that his book represents "the mainstream of thought in Pennsylvania."

Well, apparently not. Apparently, Rick is actually completely wrong on this point -- as well as completely outside the "mainstream" of Pennsylvania.