But the personas that the two men chose to present in the debate indicated the difference in a profound way. The truths of debates are these:

Emotional messages, which are variants on "how do I feel about this person?", are all that matter in presidential debates. Issues discussions are significant mainly to the extent they shape these impressions. For instance: a candidate's view on the economy feeds the impression of whether he sympathizes with "people like me." Or views on foreign policy feed the impression of whether he would be "a leader we can trust."





Barring a truly disastrous performance, each side's partisans will think their candidate did well, and will be reinforced in the reasons for supporting the person they already like. Thus John McCain supporters will think he sounded confident and masterful; Obama supporters will think he kept presenting the big-picture perspective on national security and the economy. Which means therefore:





The audience that matters is people who start out undecided or uncertain -- and finally are looking for emotional reassurance about who they can imagine as president for the next four years. In general, such viewers are only now starting to pay serious attention to the campaign -- in contrast to people already committed to helping (or stopping) one of the candidates. That is why the first debate is a unique "re-launch" opportunity for the candidates to present themselves to people who realize it's time to make up their minds.

Everything John McCain did on stage last night was consistent with trying to score tactical points in those 90 minutes. He belittled Obama with the repeated "he doesn't understand"s; he was explicitly insulting to him in saying at the end "I honestly don't believe that Senator Obama has the knowledge or experience" for the job (a line Joe Biden dare not use so bluntly on Sarah Palin); and implicitly he was shockingly rude and dismissive in refusing ever to look Obama in the eye. Points scored -- in the short term, to the cheers of those already on his side.

Obama would have pleased his base better if he had fought back more harshly in those 90 minutes -- cutting McCain off, delivering a similarly harsh closing judgment, using comparably hostile body language, and in general acting more like a combative House of Commons debater. Those would have been effective tactics minute by minute.

But Obama either figured out, or instinctively understood, that the real battle was to make himself seem comfortable, reasonable, responsible, well-versed, and in all ways "safe" and non-outsiderish to the audience just making up its mind about him. (And yes, of course, his being a young black man challenging an older white man complicated everything he did and said, which is why his most wittily aggressive debate performance was against another black man, Alan Keyes, in his 2004 Senate race.) The evidence of the polls suggests that he achieved exactly this strategic goal. He was the more "likeable," the more knowledgeable, the more temperate, etc. (Update: though from here on out he doesn't have to say "John is right..." anywhere near as often as he did last night.) .

For years and years, Democrats have wondered how their candidates could "win" the debates on logical points -- that is, tactics -- but lose the larger struggle because these seemed too aggressive, supercilious, cold-blooded, or whatever. To put it in tactical/strategic terms, Democrats have gotten used to winning battles and losing wars. Last night, the Democratic candidate showed a far keener grasp of this distinction than did the Republican who accused him of not understanding it.



