It's hard to say exactly when the moment arrived, but well into Wednesday's final presidential debate John McCain must have realized that he was not "whipping" Barack Obama's "you-know-what" and, in fact, probably was starting to fall behind on points.

That's when it kicked in, and you could see it wash over McCain's face—that feeling of distaste for Obama that I've witnessed in so many of Obama's political opponents (and some others) over the years. Call it jealousy or call it disdain, but Obama can readily elicit this emotion from people who come into contact with him.

"The looks and the disdain and the contempt and the anger that (McCain) felt were palpable throughout the middle section," observed David Gergen, the presidential adviser turned CNN pundit, in a post-debate analysis. 

In an unguarded moment a few years ago, Obama confessed to me that one of his greatest perceived flaws was his imperious air, a slight whiff that he can emit that says, "I'm just a little bit smarter than you, just a little bit better looking, a little bit more successful and talented."

I can recall a supporter of an opponent in Obama's U.S. Senate race looking at Obama onstage and commenting snidely about how Obama would hold his chin high and survey the audience "as if he's looking down at the rest of us." When Obama received a bit of unsympathetic press coverage, Obama's chief consultant David Axelrod bemoaned that the journalist was "just jealous that Obama is a better writer"—an analysis with which I tended to agree.

This can seem like smug elitism to some, outright arrogance to others or just plain confidence to his most ardent admirers. But it's a quality that cannot be denied about his persona, a quality that I believe is rooted in the extensive ego- and character-building efforts of his young mother, who worried about a potential lack of self-esteem in her biracial, father-abandoned son.

By some scorecards, McCain might have won last night's contest on substance. For the first 30 minutes or so, Obama looked tired and sounded flat. He held his eye blinks just a little longer than normal and spliced in a few too many pregnant pauses, which has historically signaled to me that he is physically fatigued. He had just spent three days aggressively campaigning in Ohio and preparing for the debate, so fatigue probably played a role in that halting tone.

But when McCain kept the discussion centered for too long on the negative aspects of the campaign, and then seemed to heap more blame on Obama for causing that tone, the match swung in Obama's favor. That's when McCain's looks of disgust grew more noticeable, and I think those uncomfortable physical reactions from McCain probably did more to sway feelings about the two men than anything that was said during the 90 minutes of give-and-take. The far senior Republican senator was sending a physical signal that he just couldn't believe he wasn't kicking the tail of this young, cool Democratic upstart.

This may be an unfair comparison, but at those moments, McCain reminded me of left-wing filmmaker Oliver Stone's portrayal of Richard Nixon—an embittered man who never got beyond his jealousy for the love and affection that John F. Kennedy engendered in so many Americans. Jealousy is one of the ugliest of human emotions, but it is also one of the rawest. There are still nearly three weeks left in this presidential race, and that can be an eternity in politics. But if McCain is to lift his sinking poll numbers, he would be well advised to suppress his personal feelings of contempt and anger, or this thing could get even uglier for him.