Although Barack Obama remains a slight favorite in this election, his position is more vulnerable than at any point since the primaries concluded, and he no longer appears to have a built-in strength in the electoral college that we had attributed to him before.
The reason is a new poll out of Ohio, where Public Policy Polling now shows the race dead-even at 45-45. In a PPP poll conducted in July, Obama had led by 8; that poll had been largely responsible for propping up Obama's Ohio numbers. Our simulation model operates quite literally in shades of color, rather than a simple red:blue duality. However, with this poll figured in, we now figure McCain to be a very slight favorite in Ohio.
Furthermore, with Ohio now trailing behind Obama's numbers nationally -- we regard Obama as a 1.0-point favorite in the national popular vote, but McCain an 0.6-point favorite in Ohio -- McCain now rates as slightly more likely to win the electoral college than the popular vote, a reversal of the trend apparent for most of the past couple of months.
If there's a silver lining for Obama in this poll, it's that his lost ground has come mostly from Democrats (he performed quite well among independents in this poll) -- a group that he will have a chance to rally next week in Denver.