KEY POINTS:
Presidential debates often get narrowed over time to the sum of small moments: Al Gore sighing and crowding George W. Bush's airspace, George Bush snr looking at his watch, Michael Dukakis being caught in the headlights with his Willie Horton moment.
The first presidential debate for Barack Obama and John McCain yielded little in the way of 'Gotcha' slogans. But it provided important impressions and illuminated differences between the two men.
Whereas Obama was crisply sombre, McCain was intense and testy.
Whereas Obama roamed widely over economic policy positions, McCain hammered his cost-cutting drive to the point of obsessiveness.
Obama then erected a frame and sketched his vision for the world like a much-read student aware he can analyse with perception and insight.
For instance, he noted that America's preoccupation with Iraq had limited its ability to compete for influence around the globe even as China gains ground in Africa, Latin America and Asia: "The conspicuousness of their presence is only matched by our absence."
McCain brought global diplomacy down to the level of a Michael Palin travelogue ("I've been to Waziristan, I can see how tough that terrain is") weaving personal stories and political connections into an at times rambling narrative that stressed his record and command of detail.
Each approach mirrored the campaigns they have run: Obama is the patient trapper laying his snares; McCain the instinctive tactician responding to wind shifts during the race.
Going into the debate, Obama needed to present a sturdy competency and sidestep his penchant for long-windedness. He did that, although there was a period when McCain's needling appeared to get under his skin. He didn't spring any zingers or funny one-liners but he held his own and didn't make any mistakes.
His best moments were on Iraq: "John, you like to pretend like the war started in 2007. The war started in 2003. You said we knew where the weapons of mass destruction were. You were wrong. You said that we were going to be greeted as liberators. You were wrong. You said that there was no history of violence between Shia and Sunni. And you were wrong."
McCain showed real passion on his favourite issue of pork-barrel spending, distancing himself from his party with "we came to power to change government and government changed us".
As McCain testified about his experience and readiness to lead, he appeared to suggest a faith in a personal approach to governing reminiscent of George W. Bush: "I know our allies and I can work much more closely with them", "I know [veterans] know that I'll take care of them", "I'm confident, now that General Petreaus is in the new position of command [over Afghanistan]."
At times his attempts to highlight his experience seemed to simply spotlight his longevity. Inevitably, there was a strong visual impression of generational difference and promise - McCain (the past), Obama (the future).
On the issues, they both showed impressive knowledge and command of policy. The view that Obama is better on the economy appears to have solidified in the polls so he was probably helped by having 40 minutes devoted to that topic.
Rather than "who won?", the better question to ask is "who improved his position?".
Obama clearly did.
He went into the debate 4.2 points ahead on the RCP poll average. He is also getting better poll results in key battleground states, although Florida and Ohio remain the toughest sales.
McCain went in as the supposed foreign policy expert; Obama will be on friendlier - domestic policy - turf for the next two debates.
At an important level Obama had the upper hand: Likeability is crucial in elections and McCain pressed the feistiness factor a bit too much.
His tactic of regularly stressing that "Senator Obama does not understand" tipped over at times into open, sneering disdain.
McCain said Obama's decision to possibly hold talks with Iranian President Mahmoud Ahmadinejad without preconditions "isn't just naive. It's dangerous".
"So let me get this right. We sit down with Ahmadinejad, and he says, 'We're going to wipe Israel off the face of the Earth,' and we say, 'No, you're not'? Oh, please!"
Towards the end he said: "I don't think I need any on-the-job training. I'm ready to go at it right now."
His big mistake: He refused to address Obama directly and look him in the eye.
Obama, on the other hand, was all calm reasonableness.
He cleverly ripped a page from Bill Clinton's book on how to debate older war heroes (Bush snr, Bob Dole). Like Clinton he managed to make forceful points without sounding disrespectful and kept control under fire.
He generously admitted McCain was right several times. His use of McCain's first name 'John' at times, rather than the usual 'Senator McCain', came across as warmly familiar. At times he looked straight down the camera.
The overall effect was to make Obama seem more bipartisan, gracious and presidential and McCain more than a bit mean-spirited. Would Clinton or Ronald Reagan have come across like that? In the contest over who was the nicer guy, it was no contest.
Not surprisingly, CNN's focus group screen worms started wriggling southwards at any nastiness. And CNN's instant polling showed women going for Obama by a huge 59-31 per cent.
McCain, at least, put questions about his impulsive decisions of the past few weeks behind him with a serious, knowledgeable performance, apart from a couple of minor stumbles. But then Obama hardly looked like the risk McCain was trying to make him out to be.
The bad news for McCain is a debate on foreign policy, his area of expertise, was his best chance of changing the race dynamics. It didn't happen.
Now McCain faces a run to polling day with economic issues full square and centre in the public's mind. He has to hope his running mate Sarah Palin can survive the Colosseum for 90 minutes on Saturday.
Once again this race is looking like Obama's to lose.
