I wrote last week that I really didn't think Joe Sestak's potential victory over Arlen Specter in the Pennsylvania Senate primary today was being driven by the left and the data I've seen the last few days further confirms that.
Muhlenberg released crosstabs by ideology for one of its final polls on the race and found that Specter's biggest leads came with very liberal voters (5 points) and somewhat liberal voters (6 points). The only ideological subgroup Sestak led with was somewhat conservative voters, where he had a 14 point advantage.
It may seem counter intuitive for the former Republican to be winning with liberals and losing with conservatives, but it has a lot to do with President Obama's injection into the race. In PA-12 over the weekend we found that Specter led 45-37 with voters who approved of the President. But Sestak led 64-16 with the Democrats who disapprove of Obama's performance (34% in that particular district) fueling his overall 44/35 lead there.
When we polled Pennsylvania statewide last month an unusually high 20% of Democrats said they disapproved of Obama. I am pretty sure Specter will be the winner among the 80% of Democrats who like Obama tonight- but Sestak could win the ones who don't by a wide enough margin to give him a victory. Thus a Sestak victory may actually be more a sign of the strength of conservative Democrats than the left- although it's an over simplification to declare either of those things to be the reason.