Democratic challenger Bob Casey, Jr. is maintaining a double-digit advantage over Senator Rick Santorum, leading 50% to 39% (see crosstabs).

The latest Rasmussen Reports election poll of Pennsylvania's U.S. Senate race shows a narrowing of the gap since June—from fifteen to eleven percentage points. But, considering the stability of this contest, the incumbent can't really say he is turning a corner.

In five of our last seven surveys, Casey's support has ranged narrowly between 50% and 52%. One exception lies above that range, the other below. Santorum's pattern is similar: between 36% and 39% in five of seven surveys—again, with one exception above and one below that range.

Senator Santorum is the incumbent, has plenty of cash, and has been pushing hard to lure less partisan voters by stressing non-signature issues like his ability to deliver pork. But he is controversial and up against a well-known challenger.

The Senator remains the nation’s most vulnerable incumbent. But he's not as lonely as he was a few months back: four other Republican Senators now also trail Democratic challengers: Burns in Montana, Chafee in Rhode Island, DeWine in Ohio, and Talent in Missouri.

Santorum is viewed favorably by 44%, unfavorably by 50%; 30% view him "very" unfavorably. He is popular enough with his base, with 76% of Republicans viewing him favorably, 48% "very favorably" (numbers that have been increasing). But 47% percent of Democrats view him "very unfavorably." And Santorum barely scrapes up a 32% favorable rating from unaffiliated voters, the group he must win over to squeak through. Fifty-nine percent (59%) of unaffilateds and 61% of moderates view him unfavorably.

Casey is viewed favorably by 66% of all voters. That figure includes 57% of unaffiliated voters and 71% of moderates. But relatively few regarding him "very" favorably, confirming the perception that the election is largely a referendum on Santorum.

Pennsylvania's gubernatorial race isn’t much closer than the Senate race as Ed Rendell (D) leads in his bid for re-election.

Crosstabs are available to Premium Members.