Joan Smith: Be afraid – Palin's weaknesses are her strength

It was like watching a sleek Afghan hound compete for best-in-show with a shamelessly winsome mongrel. From the moment Sarah Palin surged on to the stage and grasped his hand, asking if she could call him by his first name, Joe Biden seemed mesmerised by the showy antics of his rival for the vice-presidency. Ms Palin smiled, winked, invoked the deity – when this woman mentions God, it sounds as if she's talking about one of her neighbours – and name-checked a school class back home in Alaska. She described herself for the umpteenth time as a "hockey mum" and used cringe-making folksy phrases like "betcha" and "doggone it". Poor Senator Biden forced a smile, looking as if he could scarcely believe what he was hearing, and doggedly attacked the Republicans' presidential candidate, John McCain, instead of turning his fire directly on Ms Palin.

As I watched this unequal contest, I was reminded of the late Andrea Dworkin's description of right-wing women as "ludicrous, terrifying [and] bizarre". On Thursday night, Ms Palin got all sorts of things wrong, including the name of the top American commander in Afghanistan; she repeatedly failed to answer questions, diverting into areas she had been prepped to handle when she was being coached for the televised debate. It didn't matter. Widely predicted to fall flat on her face, all Ms Palin had to do was what she does best: presenting herself as the antithesis of the suave intellectual on the other side of the stage.

Mr McCain did not pick her as his running mate in order to appeal to sophisticated, liberal, educated Americans. He chose her to fill the gaps in his own CV (not least the God-shaped one); to stun the Democrats after their rejection of Hillary Clinton; and to bring on board millions of Americans who feel excluded from traditional political discourse. I don't suppose they could name General David McKiernan either, but they love it when she lines up with them as an outsider who's perplexed and offended by the elitism of America's governing class. Her target audience lapped it up last week, blogging that she had wiped the floor with Mr Biden; she didn't, but the reaction says a great deal about the kind of visceral, vengeful, anti-intellectual fantasies her rhetoric stirs up.

It's true that Mr McCain took a big risk when he chose her, but I fear that people on the centre-left have been too quick to write her off. Something similar happened in this country in the 1970s, when traditional Tories scoffed at Margaret Thatcher's challenge to Ted Heath, and look where that got us. Mr McCain is still trailing Barack Obama, and the conventional wisdom is that he's handled the current financial turmoil less deftly than his rival. But for every American who assumes people won't vote for Mr McCain in case they end up with President Palin, I suspect there's another who loves the idea. This is a woman who is ruthless in her pursuit of power, but she disguises it with displays of femininity and a kind of studied ordinariness. Hockey mums are nothing to be afraid of, after all, and Mr Biden has nothing worse to complain about than being smothered in blancmange.

Ms Palin might have had a trickier time if her opponent had been Hillary Clinton. To feminists, she is a familiar type, a right-wing woman who flatters men by reflecting their views back in even more extreme form. She's not going to upset the status quo and she's even mildly sexy, which gives her a unique selling point. The Democrats should be worried: Sarah Palin is at once the most ridiculous and the scariest woman on the planet.