True - however - if he is doing well enough to carry Michigan, he’s likely to carry Ohio comfortably as that is the more Republican of the two states.
I’m an Ohioan, so I know that Michigan is more a blue state than is Ohio. IIRC, GWBush carried Ohio both times and Michigan neither time. I’d have to check on that to be sure, but each election was very narrow in terms of the electoral college.
So, it is more unusual for a republican to carry michigan than to carry Ohio.
Therefore, if Romney wins Michigan that makes Ohio less critical, so some different routes to victory open for Romney that weren’t there 2 weeks ago.
Romney carrying Michigan could be due to his father’s ties to Michigan and not to political momentum, so in that sense, it could be something that wouldn’t necessarily affect Ohio.