Polling, especially during the convention period, is often described as a “roller coaster”, but I think the metaphor is a little bit more powerful than that. You can ride a particular coaster a dozen times, visualize the ride, and tell yourself that you aren’t going to be scared when you go down the first big hill. But inevitably, if you have genetics like mine, you’ll be still be screaming once you’ve actually strapped yourself in and are riding the damned thing. There are certain things that are so experientially intense that it’s probably impossible to fully prepare yourself for them — you can know exactly what’s coming, and it doesn’t matter.
At this very moment, John McCain has a lead of something like 2, maybe 3 points in the national polls. If I had asked you, before the convention period began, what you expected the national tracking numbers to look like on the weekend immediately following the Republican convention, my hunch is that the average guess would have been right around a Republican +2 lead — exactly where the polls are now.
Is it possible that the race has entered some sort of new steady state? Yes, of course — such things happened following the Republican Convention in 1988 and the Democratic Convention in 1992, for instance. But history tells us that far more often, convention bounces recede. And even if this one doesn’t, the absolute worst case for Barack Obama is that he’ll be within striking distance given one good debate performance, and will probably also have a slightly stronger hand to play in the electoral college than in the national popular vote.
McCain’s bounce is probably now fully manifested. I think he might pick up one more point or so in the Gallup tracker tomorrow, as I show slightly stronger results for him on Sunday (+5.0) and Saturday (+7.2) than I do on Friday (+2.7). But I don’t know that he’s going to get much more than that without further, intervening events.
Public Policy Polling also has a survey out in Michigan, which shows Obama with a 1-point, 47-46 lead. Those are better numbers for McCain than other PPP polls of the Wolverine State — he had trailed by 3 in July — but actually ought to be a somewhat heartening result for Democrats, since it means that Michigan is polling about 3 or 4 points more Democratic than the nation as a whole. I will have more thoughts today or tomorrow about the way that individual states might be affected by the convention period.
Finally, as I’ve urged throughout the convention period, take the various charts and graphs on this website with a grain of salt for the time being. It usually takes something like 5-7 days, depending on the volume of polling, for our tracking curve to catch up to the new numbers. If McCain holds onto these numbers through the end of the work week, he should be leading in the national popular vote estimate (though I’m less certain about the electoral college). Then again, maybe the bounce will recede quickly, in which case the tracker will seem prescient.