EPIC-MRA has released a new poll showing Obama with a slim 4-point lead over Romney in Michigan (47-43). This poll may overestimate Republican strength; it is weighted 38/37/21 Dem/Rep/Ind (other polls have showed a similar breakdown, but some have also found a bigger Democratic advantage). Still, it's worth noting that Romney has gained strength among independents compared to an earlier EPIC-MRA poll. He now leads Obama among independents 41-39 (after being 12 points behind him), so this poll definitely has positive news for the Romney campaign. Obama won Michigan in 2008 by about 16 points; a close race here could be suggestive of a broader weakness.
Furthermore, this poll suggests that Democratic Senator Debbie Stabenow may be vulnerable. Just 38% of Michigan voters think that she's doing a positive job. That's not a good number for a multi-term incumbent. Republican challenger Pete Hoekstra has a positive favorability rating, but he's unknown to a lot of the electorate. As he makes himself known to more Michigan voters, we might see Michigan become a battleground on the Presidential and Senatorial levels.