The fundamental law of political debates is like the fundamental law of medicine. First do no harm. To yourself. By this admittedly low standard, Sarah Palin succeeded in the Vice Presidential face off with Joe Biden. She did herself no harm; she even halted her own political tailspin.

And when 70 million people, the biggest audience in televised debate history since Carter v Reagan (and 50%?more than Obama v McCain) is watching, that was a very good thing for the Republican ticket. For Palin, the week that preceded the debate was the political equivalent of the Wall Street meltdown. After reaching dizzying, and unrealistic heights – fuelled by irrational exuberance of the Republican right – her stock plummeted so far and so fast she started looking like Fannie Mae.

A series of interviews with CBS anchor Katie Couric were, even Republicans conceded, an unmitigated disaster. Asked about the $700bn bail-out, Palin sounded like a schoolgirl who starts spouting Westlife lyrics when she's asked to analyse Milton. Her response prompted one of the most eviscerating parodies in Saturday Night Live's 34-year history.

In a bungled effort at damage limitation, John McCain muscled in on Palin's final interview with CBS, interjecting and answering questions that were directed at Palin. Alternatively cringing and grimacing, he sat beside her like a father who is giving his teenage daughter her first driving lesson – in his brand new BMW.

Every time Palin spoke, you could almost hear him shriek the political equivalent of "Brake!" Both appeared angry and combative, blaming their woes on 'gotcha' journalism, even though the most strident criticisms of Palin stemmed from her remarks to a voter suggesting that a McCain-Palin administration would embark on military adventures in Pakistan.

All week, conservative commentators, who had earlier hailed Palin's selection, questioned whether she would scupper McCain's chances in November. Kathleen Parker, a columnist with the conservative magazine National Review, urged Palin to withdraw from the ticket. "My cringe reflex is exhausted," she wrote.

The polls suggested that so too was much of America's – her approval rating dropped by more than 20 points and two-thirds of America's saying she was not qualified for the vice presidency.

It seemed the only way things could get worse would be if she pulled out her moose hunting gun and shot her running mate – à la Cheney – in the face.

An absurd game

In the US political debates, an absurd game plays out in advance. Instead of an expectation that candidates should show formidable intellectual and leadership skills, they are effectively handicapped.

If you are perceived as being smart, you have to exceed previously held perceptions to win. If on the other hand, not much is expected, a candidate is deemed to have succeeded simply by not falling flat on their face. It's a bit like pitting a Special Olympics athlete against an Olympic athlete; there can be no real winner.

When it comes to foreign policy, Biden is regarded as one of the sharpest knives in the drawer. He should be; he's had 35 years experience as a Senator, many of them spent as head of the Senate Foreign Relations Committee. As Palin has proven in utterances that teeter between excruciating and alarming, Palin isn't in the drawer – in fact she's not even in the kitchen.

So the old dancing-elephant standard applies; it's not the fact the elephant dances badly – the amazing thing is it can dance at all.

But it is to Palin's credit, and testament to her grit, that she pulled back from her own political abyss and put in a performance that, while it didn't exactly help McCain, certainly didn't add to his woes.

She stopped herself from becoming a national joke by playing her strongest cards – her telegenic appeal and her Washington outsider status. Palin has the rarest of political gifts; a natural likeability, an ability to connect with her audience that only a handful of politicians – think Clinton or Reagan – possess.

But the folksiness teetered on cloying at times; the 'doggones' and 'darns' and 'you betchas' came thick and fast. And, like Bush, the Palin alphabet comes unencumbered by 't's' or g's'.

"Oh man, it's so obvious I'm a Washington outsider and someone just not used to the way you guys operate," she said in response to a Biden answer on Iraq. As a riposte it was an awkward fit, but it was one of the pre-coached lines Palin had in her limited arsenal, and she was going to use it.

Like George W Bush, Palin can display a cockiness that belies her experience. When Biden characterised the Republican energy policy as "drill, drill, drill," she interjected "The chant is drill, baby, drill."

It was an immature little barb, but when your options for point-scoring are limited by your knowledge, you take what you can.

Biden for his part, wisely refrained from correcting Palin's blunders, including her reference to the US commander in Afghanistan, General David McKiernan, as 'McClellan'.

At times, she treated the debate as though it were a Miss Congeniality contest, interrupting a question about what she would do if she had to assume the presidency to send out a greeting to "My brother, who I think is the best schoolteacher in the year, and here's a shout-out to all those third-graders at Gladys Wood Elementary School. You get extra credit for watching this debate."

Cheesy and inappropriate

It was one of many moments that hovered between cheesy and inappropriate but there were others when Palin revealed herself as a surprisingly savvy politician. Every time Biden tried to make the connection between McCain and Bush, she accused him of looking backwards, the implication being he was the politics-as-usual candidate and she was the icon of change. Palin's "there you go again Joe, always looking backward" riposte was ripped from the old debate playbook of Ronald Reagan, but it was effective.

But for the most part, it was talking points, ducking questions and spirited attacks, the effectiveness of which were limited by a demonstrable lack of knowledge of national-security issues.

Palin was helped somewhat by questions from the moderator Gwen Ifill that were for the most part prosaic and predictable, allowing Palin to rely heavily on pre-coached responses.

And there were gaffes – including one where she seemed to claim additional constitutional powers for the vice president in the legislative branch. It was one of those dangerous moments for Palin when she clearly didn't understand the question and gave a largely incomprehensible answer which suggested that not only did she support the power-grab of the Cheney vice presidency, as VP she would expand it further.

It allowed Biden an opening in which he excoriated Cheney as the most dangerous vice president in US history.

Biden – who can be gaffe-prone, self-aggrandising and verbose – was serious, statesman like and
displayed a deep knowledge of his topics. The Obama agenda and the case against McCain was effectively laid out, and in the flurry of polls that were conducted by
various news channels and networks after the debate, he emerged as the clear
winner.

But after the near frenzied anticipation, nothing has changed and McCain's slide in the polls – triggered by his mishandling of the economic crisis – has not been halted.

Now that The Sarah Palin Surreality Show has ended, the focus has reverted wholly to the economy. The days when the political dialogue was dominated by chatter about lipstick and moose burgers are over. While the economy remains at the top of the agenda, McCain, who gambled on a cultural war, will swim against the tide.

'Ordinary' Americans may have found Palin more appealing. But ordinary Americans have learnt a sobering lesson over the past eight years; the presidency requires a person of exceptional intelligence, courage and wisdom, not the hockey mom next door or the windshield cowboy from Crawford.