Pennsylvania will be closely tied to Ohio, as will Michigan. The better Bush does in Ohio, the better he will do in the other two. I think Ohio will be the easiest to win, followed by Penn., followed by Michigan. Bush will probably do four points worse in Pennsylvania than he does in Ohio, and eight points worse in Michigan. So...
If Bush wins by five points in Ohio,
he takes Penn. by one point,
and loses Michigan by four.
If Bush wins Ohio by nine points,
he takes Penn. by five,
and takes Michigan by one.
Or some correlation very much like that.
Michigan seems out of reach for Bush IMO. Pennsylvania, Ohio, and Florida will decide this election. Whoever wins 2 of 3 wins the election. The only other way I could see it is Kerry could win just one of them, but pick up WV, NH, and AZ.
