Rupert Cornwell: Fame and money: why Sarah Palin won't run for the White House in 2012

Her name will not be found on any ballot form in nine days' time. Nor does it feature in the headline story of these US mid-term congressional elections – whether the Republicans can seize control not only of the House of Representatives (which looks a foregone conclusion) but of the Senate as well.

Neither will the lady have the starring role in the minor features that will appear on 2 November. Will Sharron Angle claim the biggest scalp of the night in Nevada, by defeating Harry Reid, the top Senate Democrat? Will Republican Mark Kirk capture President Barack Obama's former seat in Illinois – the one the state's former Democratic governor once put up for sale? Can the witchcraft-dabbling, masturbation-averse Christine O'Donnell pull off the ultimate shock in Vice-President Joe Biden's old seat in Delaware? The answers: maybe, probably, and absolutely not.

I refer, of course, to Sarah Palin. Like it or not, she is the story behind the story this autumn. And not just on the political pages. Her taste for "rump-hugging skirts, designer jackets and knee-high boots" inspired a two-page analysis in the "Fashion & Style" section of the The New York Times last week. The paper contrasted this unabashedly feminine wardrobe with the conventional pantsuits worn by "men-mimicking" politicians such as Hillary Clinton and the Democratic speaker, Nancy Pelosi. In fashion as well as ideology, it seems, the former governor of Alaska is the standard-bearer for a generation of younger, more assertive female candidates in 2010.

But the true story behind the story does not concern clothes. It is whether the running mate John McCain plucked from obscurity two years ago will try for the top job herself in 2012. That question will be resolved within a few months at most, and very possibly before the new 112th Congress assembles in early January. Right now however, the short answer is, nobody knows.

"Keep 'em guessing, Ike," was the advice a friend gave then General Dwight D Eisenhower, when both parties were making overtures to him, and no one knew whether he would run for the White House in 1952. Palin is indisputably a Republican, but otherwise she is following that strategy to perfection.

Look at it one way, and there seems little doubt she will be a candidate. Earlier this month, she met 50 conservative leaders whose support would be vital if she entered the race. She has made speeches in Iowa, where caucuses will kick off the 2012 primary season 15 months hence. Her every remark, her every tweet, is parsed for clues.

Few, on the face of it, were bigger than the one she dropped the other day on Fox News, where she is a regular guest and contributor. "If the American people were to be ready for someone who is willing to shake it up, and willing to get back to time-tested truths ... and if they happen to think I was the one, if it were best for my family and for our country, of course I would give it a shot." For supporters that was as good as a green light. And not by coincidence is a new Palin book coming out in November, entitled America by Heart: Reflections on Family, Faith and Flag – exactly the boiler-plate stuff every presidential candidate churns out on the eve of a campaign.

In reality though, things are anything but clear-cut. Yes, she has a great deal going for her. She is vastly popular among grassroots conservative activists who love her "Mama Grizzly" schtick and bought two million copies of her first book, Going Rogue. She sits alongside the Republican kingmakers of Fox, garnering free TV exposure her rivals would kill for. Her fundraising prowess is unequalled by any member of her party. Her name recognition is sky-high, at a moment when Republicans are leaderless and charisma-deprived. She is ferociously anti-Washington, yet simultaneously her party's most visible link with the Tea Party movement that has provided so much of the energy behind the Republican's probable victory in nine days' time.

Yes, she says (and does) some silly things. Remember, though, how snooty liberals used to mock George W Bush for hisintellectual grasp and his mangling of the English language, just as they do with Palin now. Bushisms, notes Jacob Weisberg, the leading expert in the field, were usually single malapropisms, whereas Palinisms "consist of a unitary stream of populist blather". But that's no reason why she might not be "misunderestimated", just as Bush was in 2000.

But, in political terms, Sarah Palin has problems Bush never had. Only 22 per cent of Americans, according to a CBS poll last week, think she is up to the job, against 64 per cent who think she is not. And not only Democrats and independents feel that way; a plurality of Republicans do as well. Tellingly, a number Republican candidates with a chance of toppling a Democrat in what was Obama territory in 2008, now refuse to share a platform with her, for fear of alienating independents about to transfer their allegiance.

Nor, by some accounts, is the Republican high command enamoured of her. Palin is said to have slighted Iowa's veteran and highly popular Republican Senator Chuck Grassley – not the sort of thing you do if you want his help in the caucuses.

More basically, why should she subject herself to the merciless scrutiny of a White House run if there's no real chance of ultimate victory? As a candidate, she would have to debate. She'd have to venture outside the Fox cocoon, and thus risk disasters such as the 2008 interview with Katie Couric. More dirty linen in Alaska is rumoured, not to mention the complication of a family some of whose exploits belong on reality TV.

In short, Sarah Palin already has it made. She is rich and famous, she has power without responsibility. "I know I can certainly make a difference without having a title," she also said recently. "I'm having a good time doing exactly that right now." I believe her. That's why she won't run. You read it here first.