Okay, here's your confidence.
Let's figure out how many voters the average elector represents per state. You will quickly find that it takes far fewer voters to represent an elector for traditionally red states than in traditionally blue states. Think Wyoming, Utah, Dakotas, Alaska -- very few people per elector, whereas many blue states have a larger number of people per elector (New York, California).
What does this mean? It means that Obama is at a significant disadvantage where the electoral college is concerned. Plus, many of the little states are already at a saturated point. How many Obama '08 voters are you going to flip to Romney in Oklahoma? Not many at all!
You also have to consider that the states are not totally separate battlegrounds. Sentiments in one state will spill over to another. It's impossible for Obama to win SC without winning NC, and impossible for Romney to win MA without winning CT. That kind of thing. The only state that has really bucked the trend as establishing itself apart from its neighbors in my memory is Indiana in 2008. What this means is that, generally, you can't make a blue state a little less red without lifting up their neighboring purple states to be redder as well.
So what does this mean -- IMO, it is all but impossible for Obama to win the electoral vote without winning the popular vote. He has a heavy disadvantage towards it in the first place, and momentum seen in (say) NC *is* going to spill over to VA, and momentum seen in PA/MI/WI *is* going to spill over to OH. IMO, either (some of the) OH polls are wrong or the national polls are wrong. If you believe that Romney is leading nationally, believe he's going to win the election altogether.