A different way to look at the horse race

Polls continue to shift in Obama's favor. However, if you take a look at CNN's Electoral College Map, a slightly more worrying picture emerges. Assuming that no states currently classified as "lean McCain" end up throwing their electoral votes to Obama (in other words, assuming that the election is close), McCain will win the presidency if he wins all of the following states:

Florida
Ohio
Virginia
Missouri
Nevada

According to RealClearPolitics, the current polling margins in those states are:

Florida - McCain +5.0
Ohio - Obama +5.3
Virginia - Obama +0.5
Missouri - McCain +7.0
Nevada - tie

I am not exactly reassured. Now, a lot could change - McCain could collapse when the nation sees him on stage next to Obama, Bob Barr could siphon away a significant number of votes, etc. But without such a dramatic stroke of luck, Obama remains at an electoral disadvantage - namely, that a lot of black people are concentrated in Deep South states that have no chance of voting Democratic, while conservative whites typically have slim majorities in places like Florida, Ohio, Virginia, Missouri, and Nevada.