No one's calling Pennsylvania yet, but I don't see how Sestak can make up 60,000 votes with Montgomery County all reported in. Poor Specter--damned if he did, damned if he didn't.
Could Democrats have kept Pennsylvania if they hadn't mounted that primary challenge? Specter would presumably have peeled off some Toomey votes from center-right types. Tea parties shot themselves in the foot in Delaware, and maybe Nevada; the progressives might have done the same in PA. On the other hand, as long as they barely keep control of the Senate, how much does it matter?