But what if there is a huge surge in Republican voting? Well, this would be felt across all states, at least somewhat, and should be turning the purple states red. But regardless, I took Linzer’s model, assumed a 20 percent increase in turnout in the red states (those projected to go for Romney by more than 8 percent), and assumed a 6 percent net increase in Romney’s vote share over the baseline projection. The result? Romney wins the popular vote by 0.7 points, still less than the current RCP Average.

You can poke holes in this model, to be sure, but I think the simplest explanation is that the state and national polls really are saying different things, at least for now. In other words, if you are calling for the state polls to be right, you are pretty much necessarily calling for the national polls to be wrong, and vice versa.

How do we resolve this? Which will be correct? My best answer is “I don’t know; it is a source of uncertainty in projecting the election.” I suspect one group of polls will converge upon the other in the next week, and we’ll get a better idea.