There is a lot of nervous buzz today about the national tracking polls. Gallup now gives John McCain a 2-point lead, the first time he has had an advantage of any amount since late May. Rasmussen, meanwhile, has the race converging back into a tie, after having shown Barack Obama ahead by 3 points yesterday.
This tracking polling will NOT reflect any convention bounce (or its absence). These polling firms concluded their interviews by mid-evening, before Michelle Obama's speech and before network coverage of the convention began. So if there is a response to the events of Monday night, it will show up in the field on Tuesday, which means that it will be reflected in polls released on Wednesday. Moreover, our research has concluded that there typically is not any bounce until the third day of the convention. As such, this polling tells us nothing at all about the convention so far, and it probably won't tell us a whole lot until at least Thursday or Friday.
It might tell us something about Joe Biden. I tend to agree with the conventional wisdom that there was liable to be a bit of a near-term backlash whenever Obama announced his VP choice, provided that the VP was not Hillary Clinton. The key phrase in there, however, is "near-term". If Hillary is able to rally her supporters to the Obama-Biden ticket tonight, there could still be a latent/lagged VP bounce for Obama that gets rolled up into his convention bounce.
Besides all that, we also have a number of state polls today which generally look pretty decent for Obama.
Yep, Quinnipiac released its "big three" swing state polling this morning. The results are literally identical to last month in Pennsylvania, where Obama leads by the same 49-42 margin, and essentially identical in Ohio, where Obama's lead is down from 2 points to 1 (although with undecided and Bob Barr improving). The difference is in Florida, which swung from a 2-point Obama lead to a 4-point deficit. Obama's investment in the air wars in Florida does not appear to paying immediate benefits. Still, this result is about where other polling firms had shown Florida, as Quinnipiac had been a modest outlier before. And that Obama's lead is holding relatively steady in Pennsyvalnia should reassure his supporters.
There is also polling out in North Carolina (PPP) and Texas (Rasmussen), which shows North Carolina and Texas at the same margins they have been polling at since antiquity, with McCain holding a 10-point lead among Texans and a 3-point lead among Tarheels.
EDIT: To clarify one thing: how can I imply that some of these state polls are good for Obama when they show his numbers -- at best -- holding steady? Because they beat the model's expectations. Our model had already anticipated about a 2.5-point decline for Obama since the last time these Quinnipiac polls were in the field in late July, and that decline was already priced in to our numbers. That turned out to be prescient in Florida, where his numbers slipped by 6 points. But Obama polled somewhat more strongly than anticipated in both Pennsylvania and Ohio.