I think the Romney people are looking at their inside numbers, and believe that they are winning, or close to it, with momentum on their side. I think the Obama people are watching their lead of the summertime slip through their fingers with little they can do about it other than to sling one more $100 million worth of slime at Romney. Going all-negative and throwing hopey-changey under the bus.
Hence the nature of the "debate" last night, with Romney rising amiably above the fray while Obama irritably yipped and yapped and snapped at him like a sharp-toothed puppy trying to get a rise out of a big dog.