Polls in 23 states today. Category changes in only 2.
Ohio (20 ev): After a few days as a "Weak Obama" state, Obama's lead in Ohio once again drops below 5%. That makes Ohio a swing state again. Woo! This change puts Ohio in reach for McCain again, which substantially boosts his best case scenario.
Arizona (10 ev): John McCain's lead in his home state of Arizona, which has been above 10% since September, once again falls below 10% in the last five poll average. This moves Arizona from "Strong McCain" to "Weak McCain". Since we aren't changing the list of swing states, this has no effect on the overall situation summary.
McCain Best Case - Obama 286, McCain 252
Obama Best Case - Obama 393, McCain 145
If everybody gets their leans - 364 Obama, 174 McCain
Really, not much has changed for the last several weeks. Several states have bounced back and forth between "Lean Obama" and "Weak Obama" and thus in and out of swing state status. But since October 3rd, we have continued to have a situation where McCain winning all of his own leaning states, then stealing all of Obama's leaning states, would still not have enough electoral votes to win. The only thing that has really been changing has been just how much of a loss McCain's "best case" is.
To win right now, McCain has to do better than the "best case" that I describe. He not only has to hold all of his strong and weak states, win EVERY swing state he is ahead in (Georgia, Indiana and North Dakota), and ALL of the swing states Obama is ahead in (Florida, Ohio, North Carolina, Missouri and Nevada). He also has to win at least 18 electoral votes from states that Obama is more than 5% ahead in. That means he must take Virginia and then either Colorado or New Mexico.
Or, yes, Pennsylvania would do it too rather than the combinations above. But Obama's lead in Pennsylvania is much larger than in the states above. John McCain seems to think Pennsylvania is an easier state to move though. So far, the polls have not supported that idea. But maybe he knows something we don't.