@blatham,
I don't think this one is propaganda -- I think it's very possible and that the Obama campaign is very, very smart to guard against complacency and/ or overconfidence.
I do think that was part of what happened in New Hampshire for example (and I think Obama was smart to bring that up). The polls showed that he'd win handily, the campaign got a little cocky (did the big rallies rather than the smaller town halls they'd been doing, and that Hillary was doing while she campaigned there). The press had him coronated, pretty much. And people reacted against that -- oh, you think you know what to expect, eh? Well you've got another think coming.
Of course the McCain campaign is interested in a comeback narrative, but I really don't think it's as simple as that. I think there isn't some objective reality of what will happen in the next two weeks -- I think certain scenarios are more or less likely but what the campaigns actually do has an impact. Obama is handling this stretch very, very well. McCain is not. If McCain tries for another big game-changer or just overreaches with the slime (Ayers has already been shown to NOT be effective) then things could still open up in Obama's favor. But a few things could happen that would mean advantage McCain, too.
Just two weeks left/ a whole fourteen days left. Lots could happen yet.