Just as Ohio and Missouri are the top two Republican Senate seats I would predict could flip, Pennsylvania is a top seat held by Democrats I could easily see fall the other way*.
So when Quinnipiac says Joe Sestak tied Pat Toomey again, I’m not surprised a second.
Democrats were always going to come home to Sestak in reasonable numbers, but as long as independents favor Toomey, as Quinnipiac says they do 44-35 (MoE 2.7), the situation is good for the Republican. After all, the state that has last voted Democrat for President, Governor, and twice for Senator is not supposed to yield a 43-43 tie for Senate, is it?
* If not for the disaster in North Dakota, Pennsylvania might be the top seat at risk for them.