We are now several weeks into the weird humiliation that the Republican party inflicted upon us Americans with their choice of Sarah Palin as their nominee for Vice-President. Here we are, at as precarious a crossroad as history is ever likely to offer up, yet there stands Sarah Palin regurgitating George W Bush's 'good guys-bad guys' baby talk. I despair.

When I hear her failing to recall the name of a single newspaper she'd ever read, I feel willing to offer up my teenage son as a sacrifice to the Republican party; he could serve in her stead with so much more fluency. When she prattles smoothly yet non-responsively to questions about the war, economics or foreign policy - or when she brightly changes the subject altogether - I want to weep.

Palin is a never-ending train wreck of ignorance, inconsistency, outright contradiction and sneering. During her debate with Democratic vice-presidential nominee Joe Biden, she chatted up soccer moms and hockey moms, her mom and her pop and, by golly, yours too. She winked and she dimpled and 'goshed' and 'doggoned' it. She gave a 'shout-out' to some third graders in Wasilla, promising 'extra credit' for staying up to listen.

Less remarked upon was the substance. Despite the enormous variety of public crises we face, she dismissed virtually all forms of government regulation by invoking 'private contract' rather than collective duty; 'personal responsibility' rather than public oversight; and 'tolerance' rather than civil rights. She misspoke the name of a commanding general, she went unchallenged when she expressed her arch-creationist belief that humanity has had no hand in global warming, tucking all that away cosily but dismissively: 'I don't wanna argue about causes.'

Similarly, Palin was unchallenged in her head-spinning assertions about the powers of the vice-presidency, endorsing an unqualified 'flexibility' possibly exceeding Dick Cheney's assertion of a vastly expanded, alarmingly imperial concept of a 'unitary executive'. At the same time, her answers were so vague and addled that it was hard to tell if she actually knew what she was saying.

Yet the morning after the debate with Biden, polls showed that the race was still too close to call. If Biden 'won' based on knowledge and experience, it was not by enough of a margin to inspire a significant shift. Indeed, pundits of all political persuasions were dissecting Palin's ability to 'hold her own' as though it were an actual measure of whether she could run the republic. Pat Buchanan, gleeful mouthpiece of the far right, celebrated Palin as 'a fresh voice' with a 'new vocabulary'. 'She tossed away the questions,' he gloated as though this were a good thing. 'She answered what she wanted to.'

Presenters on Rupert Murdoch's Fox News channel lined up to decry the way 'we journalists' tend to 'value knowledgeability' while true Americans 'connect to her style'. Greta Van Susteren, an experienced lawyer and ubiquitous television commentator, opined: 'Whether I agree with her or not, the important thing is whether she's plain-talking ... I may have had the fancy education, but I love the plain talk, the direct words. I'm a Midwesterner.' (Whew. Whatever is the value of a fancy education if not to inoculate against such blather?)

The enthusiasm for the Alaskan governor reminds me of an exercise I once conducted with students. I played them a segment of the 2007 debate between Ségolène Royal and Nicolas Sarkozy. Very few understood French, so it was effectively an exercise in reading body language. They were convinced that Royal had won the argument because she seemed 'emphatic' and 'passionate' and 'repeated her points a lot'.

The clip I had played, however, was Royal's least convincing moment in that debate: she was delivering a mawkish, inappropriately long-winded tongue-lashing about Sarkozy's purported failure to tackle the plight of handicapped children. Although her body language might have telegraphed earnest conviction, the words she was repeating with such focused intensity were something along the lines of: 'I am not going to pieces, I am angry, I am angry, I am angry.'

Even if one's political sympathies lay with Royal, it was clear why that encounter might have lost her the election. My students accurately translated Royal's passion and conviction. They also accurately translated Sarkozy's discomfort at that moment. But without an understanding of the substance of what was said, it would be impossible to see how much her words contradicted the commanding body language.

The enthusiastic responses to Palin's presentations remind me of that exercise. Yes, Palin's delivery is perky and self-assured. But if one pays attention to the substance, it's impossibly vacuous. That so few do pay attention makes me think that listening to the debates must be like a foreign language for some of my compatriots. Perhaps this is laziness or political illiteracy. Perhaps it's a failure of education. Perhaps there's a measure of raw racism: better to vote for anyone other than the black guy. Or perhaps it's a manifestation of gender fundamentalism, by which any biological formation of a woman can stand in for Hillary Clinton.

At least as distracting are the polarities jumbling American political discourse: i.e. not just good versus evil, male versus female, black versus white, but eastern elitism versus western frontier spirit; secular humanism versus speaking-in-tongues theocracy; scientism versus creationism; 'tolerance' versus equal rights; ultra-libertarianism versus civic engagement.

The Republicans' best operatives have been playing these tensions against each other for decades. Against the backdrop of such a frighteningly incoherent cultural landscape, Sarah Palin plays Mom. She speaks to us in a wipe-your-nose and sit-up-straight inflection that is quite Orwellian - if Orwell had anticipated that newspeak might come packaged as old-fashioned-country-horse-sense speak.

And so we love her, Mother Sarah. She's simple, she's pretty, she's as fierce as a tiger protecting her cubs. So what if storms are rattling the windowpanes? We get a glass of warm milk and a big gold star just for staying up late while she tells us reassuring bedtime stories.

• Patricia Williams is a professor of law at Columbia University and a regular columnist for the Nation magazine