Because supposing the Republicans win in 2008, then it is likely that they will either hold all the Bush states or expand into the purple states.
Or the Bush states splinter and they expand into the Democratic states. I can see the GOP losing Ohio while taking a state or two that went for Kerry.
Because Wisconsin and Minnesota are swing states, the likelihood of it being won by a Republican increases if a Republican wins the presidential election.
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Obviously. They're more likely to go Republican in that case, not "likely." There's a difference. In any case, I wouldn't be surprised to see Wisconsin go Republican in '08, but I really doubt that Minnesota flips. That state has been "trending Republican" for about three decades now.
Well, supposing that everything is 50/50 in '08, you can add in the convention factor. Then there is Tim Pawlenty - there is a very good chance that he will be the vice presidential nominee. With Pawlenty on the ticket, Minnesota is almost a certain Republican pick-up.