Wisconsin, Michigan, Minnesota, Oregon, Pennsylvania, and Washington if McCain is the nominee.
Lol.
Seriously. Only states won by Clinton, Gore, and Kerry could potentially be close, right? Even Dukakis won all of those except Michigan and Pennsylvania.
Pennsylvania
Obama - 54.48%
McCain - 44.17%
Michigan
Obama - 57.37%
McCain - 40.92%
Wisconsin
Obama - 56.22%
McCain - 42.31%
Minnesota
Obama - 54.06%
McCain - 43.82%
Washington
Obama - 57.43%
McCain - 40.32%
Oregon
Obama - 56.75%
McCain - 40.40%
To be fair, McCain probably did better in these states than, say, Huckabee would have.