Wisconsin has long been an interesting state, fairly rural but with a high-proportion of well-run family farms. It's usually been an example of D.P. Moynihan's Close to the Canadian Border effect (except for its blacks, who appear to have been largely recruited from the South by the generous European-style social benefits offered post WWII).
A reader tries to make sense of recent voting changes on a county by county level, using the evenly split 2004 Presidential election as a baseline:
 that among conservative Catholics there has been a distinct upswing in favor of the Republicans and  that among lax Catholics there has been an equally distinct, albeit not so pronounced upward swing. Specifically, in the 2010 governorship race, conservative 'over-voted' their 2004 baseline numbers by an average of 3.5%. In the 2012 recall election, they 'over-voted' the 2004 baseline by almost 14%. Among lax Catholics the 2010 'over-vote' was about 3%, whereas in the 2012 recall it was almost 8%.
I suspect that the 2010 shift in favor of the Republican side was, to at least some extent, a referendum on the Obama Administration's economic performance. I further suspect that--again, to at least some extent--that the significant upward swing in 2012 reflects anger with the ham-handed behavior of the Administration in regard to the medical insurance mandate relating to abortifacients. If my data reflect reality and if my interpretation of these data is anywhere near accurate, I believe that Mitt Romney has an reasonable chance to carry Wisconsin in November.
Managing a Coalition of the Diverse is always going to be a challenge, especially if the opposition tries Divide and Conquer techniques on them.