Rasmussen has just released polling from five key swing states. When coupled with PPP's new poll of Michigan and SurveyUSA's new release from Virginia, we see a race that is relatively unchanged from the pre-convention period, but with incremental trends in different states that might portend changes in electoral strategy:

State/Pollster WAS NOW SWING
OH Rasmussen McCain +5 McCain +7 McCain +2
MI PPP Obama +3 Obama +1 McCain +2
PA Rasmussen Obama +3 Obama +2 McCain +1
VA Rasmussen McCain +1 McCain +2 McCain +1
VA SurveyUSA McCain +1 McCain +2 McCain +1
FL Rasmussen McCain +2 TIE Obama +2
CO Rasmussen McCain +1 Obama +3 Obama +4
AVERAGE McCain +0.6 McCain +0.7 McCain +0.1

A few thoughts, and caveats:

The best news for McCain at a micro level is that he appears as though he might have gained just a tiny bit of ground in the Midwestern Rust Belt states, something which may also have been reflected in the new ABC/WaPo national poll, which showed him performing well in the Midwest. I still think that Pennsylvania isn't going to close quite enough for him to qualify as a top-tier swing state, especially as there are a lot of Clinton voters out there who should be returning to the Obama ticket. But Ohio now looks like it probably isn't Obama's path of least resistance to 270 electoral votes, and I'd expect Michigan to continue to be very competitive.

The best micro-level news for Obama is in Florida, where there are a couple of favorable dynamics in play:

(i) the Joe Biden selection probably went over well there;
(ii) the consolidation of the Clinton vote is also valuable in Florida, and
(iii) something is likely to be lost in translation between Sarah Palin and swing groups like Jewish voters and Cubans; moreover, Floridians tend to be fairly socially liberal but more conservative on fiscal and foreign policy, not necessarily the best match for Palin's politics.

We need more evidence to confirm this, but at this point, it feels to me like Florida is a better target for Obama than Ohio.

It also looks to me like the Palin selection may have increased the income/economic gap. That is probably good news for McCain in Ohio and good news for Obama in states like Colorado. It theoretically might also be good news for Obama in Virginia, but I think his gains there might be offset by McCain consolidating evangelicals.

At a macro level, these numbers seem like basically good news for Obama, since the overall numbers in swing states haven't moved much at all - just shifted around some from region to region. McCain is polling about 3 points better right now than he was at the pre-convention equilibrium. It's possible that those 3 points are manifesting themselves mostly in states that were already very red. Maybe Obama will lose Idaho and Nebraska and Alabama by 30 points rather than 20, but that doesn't help McCain very much electorally (an exception might be in a state like Indiana).

In other words, I suspect that the probability of Obama winning the electoral college while losing the popular vote probably increased as a result of the post-convention dynamics. If you literally just looked at the polling out today, McCain would win the popular vote by 2-3 points, but Obama would probably be at least even money in the electoral college, by just barely holding onto Michigan and Pennsylvania and then either winning the Colorado/Iowa/New Mexico parlay, or perhaps Florida.

--Nate Silver