David Frum remarks on Mitt Romney's win that "Michigan faces some of the worst economic troubles in the nation. Romney addressed those problems in a more sustained and detailed way than his main Republican challengers in the state (Huckabee, McCain)." Ross dubs this "absolutely right." And it sounds right to me. But I'm not sure the exit polls bear it out -- Romney did better among voters who think economic conditions are good than among those who think it's bad.
Similarly, Romney did better among voters making over $50,000 than among voters making less than $50,000. He did better among college educated voters than among those without college education. It's true that he did best among voters who named the economy as the most important issue, but the businessman candidate's main constituency seems to be among affluent business class types who aren't feeling an especially large amount of economic pain. More primaries and more polls should give us more data, but provisionally it's not clear that "economic troubles" are really all that central to his appeal.