Another potential factor is D’s voting R.
Reagan pulled a huge chunk of votes from registered D’s, blowing away the projections.
There is a significant Jewish vote in PA, and a huge Catholic vote, which probably won’t be voting as D as they used to be. There are bitter clinger D’s, and coal miner D’s, and unemployed long time D’s.
There has been been a lot of talk about relative D or R strength in registering, early voting, absentee and enthusiasm.
There has been a lot of talk about how much independents are leaning R or D.
But I have not heard much from the number crunchers (Rove and such), of how many registered D’s will cross vote.
If anyone could stampede some cross voting, it’s this once-in-a-hundred-year-flood disaster of a President.
Obama Must Be Defeated!
My Dad, very conservative, nearly ninety, registered as a Democrat during WWII. The last time he voted for a Democrat for any Federal office was Truman. But, he doesn't want to deal with changing registration. I've told him it's completely painless. I change Parties just about every other two-year cycle just to cause problems for the Dems if a Republican is unopposed or it's clear the right 'Pubbie is going to win. Still can't convince him.
Given that PA has the fifth oldest median age in the country -- tied with geriatric Florida -- there is probably some percentage of people like him. The nominal Dem advantage is +13. The active registration advantage is D+12. It's lower than that, but this is still a "union shop" and consequently a heavy Dem state. We win the mid-terms pretty reliably, because the Dems are so lazy.