Bush is Ahead, But He's Behind

A little more on the incumbent rule from MyDD, estimating that if the election were held tomorrow and 80 percent of the undecideds went to Kerry,
Kerry would win 304-234, taking Florida, New Hampshire and Ohio, but losing Iowa. (N.B. This calculation was made on October 22nd; it doesn't take into account more recent polls which suggest that the race has tightened.)

Your mileage may differ. The basic point is that you must keep your eye firmly fixed on the President's numbers in the battleground states. If he polls at 49 or 50 percent or above, he's in ok shape. But if he's polling at 47 or 48 or lower, even if he's currently ahead, he's toast.