It is interesting that NW Ohio trended heavily to the Dems in 2008, which the rest of the state either trended to the GOP, or had no trend. Next door Indiana trended evenly more heavily to the Dems. It would be interesting to speculate why the partisan trend went one way on one side of the imaginary line taking in NW Ohio and Indiana, and parts of Illinois and so forth, and the other way on the other its other side.
I think there are a few Al posts on this subject, if not a few Sam Spade ones too.