With all due respect to Judis, I'm not popping anything just yet, except maybe some sleeping pills to get me through the night. (That's for you, John.) In the last few days, pretty much every tracking poll I trust (WaPo, Gallup, Rasmussen) and several I either don't trust (that would be you, Zogby) or don't have much of an opinion about (Kos, Investor's Business Daily) has shifted toward McCain, in some cases sharply. While some of the more traditional (i.e., non-tracking) polls show Obama with a big lead--like the Pew poll Judis cites--these polls tend to reflect older information.
As of this writing, Obama's lead in the national tracking polls looks to be around five points (I get 5.5 when I average all six of the trackers I mentioned, along with the Hotline and Battleground trackers, which haven't changed much in the last few days). If that drops two-to-three points, as it easily could in a week, I don't think it's crazy to think McCain will have a shot at winning Pennsylvania, Virginia, and/or Colorado. Unlikely, yes, but not crazy. According to sites like Real Clear and Pollster.com, Obama's lead in those states is currently larger than his 5.5 point national lead (significantly so in Pennsylvania). But, as I argued last week, the relationship between battleground-state numbers and national numbers can change significantly as we approach the finish, and those state averages you see could easily be a week out of date.
My immediate concern is twofold: That McCain is getting some traction with his liberal/socialist/redistributionist charge--the WaPo tracker shows McCain narrowing the gap on the economy over the last week--and, in light of this, that Obama is striking his high-note a few days too early. I'd feel more comfortable if he roughed McCain up a bit longer (though, in fairness, his "closing argument" speech is very good and it does take some swipes at McCain. Also, it's not like the campaign isn't still running tough ads.).
Be sure to check out Judis' response here.