DJ Drummond of Wizbang has an interesting question:

So, put it all together, and in the past week Obama has stayed steady or lost support in every party identification group, yet Gallup says his overall support went up four points. And McCain stayed steady or went up in every party identification group, yet we are supposed to accept the claim that his overall support went down by four points? Anyone have an answer for how that is even possible?

Drummond has an answer. Read the whole thing.