It does look like Romney's team has realized that Obama's ground game and focus on early voting in Ohio makes Ohio so unlikely to win that they have switched to a "Wisconsin Plus" Plan. Also, the Obama's auto bail-out bragging rights makes Ohio too intractable. It's a great issue for Obama but one he does not have in Wisconsin or the other states.
The idea is that Wisconsin is softer territory for them. And they have the native son in Ryan. The Republicans have the remnants of their ground game after they won their battle against Scott Walker's recall. (Of course stopping the Scott Walker recall was only because some voters believed that to recall a person they should be accused of some kind of crime).
The problem is to get the Electoral College votes they need they would have to couple a Wisconsin turnaround with another state's turnaround which could be New Hampshire (most likely), Iowa (less-likely since Romney wants to kill the wind industry) or much less-likely Nevada (which is has a significant Latino population).
New Hampshire is small and a bit mercurial in its voting. Iowa is relatively small as well. Any of these combined with Wisconsin constitutes a smaller voting segment that they have to change as compared to Ohio.
An interesting thing is that according to RCP, Obama's lead in Ohio, Wisconsin, New Hampshire, Iowa and Nevada is currently almost exactly the same - about 2.3 percent. Nonetheless, Huffington Post Pollster has Obama up four in Wisconsin and Nate Silver has Romney's chances there at only 14% -lower than Ohio and all the other states.
Whether they stay fighting hard in Ohio or switch to Wisconsin and the other states they would have to win in both Colorado and Virginia where Silver gives Obama about a 60% chance of winning.
It will be interesting to see if the campaign shifts to the four states of Colorado, Virginia, Wisconsin and New Hampshire.
Maybe it already has.