One interesting thing about the demographics break down of the poll is that its about 88% white while the state's voting age population is closer to 83%. Not saying the real world demographics are going to represent election day, but if the actual results reflect this poll, then there's still room for dems to grow in Ohio by increasing minority turnout next election.
As for Portman vs Stricklan, the short of the long is, Portman went on air early with very misleading ads claiming his opponent destroyed the Ohio economy (which isn't true, as he was governor during the 08 economic collapse, not his fault) which has really set the race early.
Every race has a deluge of negative ads. Toomey and the Republicans have run tons against McGinty as well. I don't get why it had such an effect in Ohio but basically none in other races, since they more or less cancel each other out. For whatever reason it seems like Dems have a very low floor in Ohio that isn't present in other states.
