At the State Fair Park in the Milwaukee suburb of West Allis nine days ago, Sarah Palin made her first major public appearance since resigning as governor of Alaska back in July. Despite strict entry conditions banning laptops, mobile phones, and cameras, an estimated 5,000 people paid $30 to hear her speak for 25 minutes at a fundraiser organised by the Wisconsin pro-life movement. Denied official media access, journalists had to buy tickets in order to hear a speech that, like everything else she does these days, created instant headlines.

In the course of a wide-ranging attack on abortion, the former vice-presidential candidate speculated that, under the proposed new healthcare system, those who support terminating pregnancies might also be inclined towards killing off old people. The sort of conspiracy theory beloved of the conservative right, it was a revival of her long-standing allegation that the Democratic administration wants to introduce "death panels" to decide whether patients live or die.

"What may they feel about an elderly person who doesn't have a whole lot of productive years left?" asked Palin. "In order to save government money, government healthcare has to be rationed so [what] then of this elderly person that perhaps could be seen as costing taxpayers to pay for a non-productive life?"

Apart from delighting the crowd, those lines caught the eye of the national papers, and, as is now the norm, neatly divided America in two. It invigorated her followers and appalled her detractors, and the reaction to this comment offers the perfect prism through which to view the most polarising politician in the country.

On the right, it was taken as yet more evidence Palin is a fresh, dynamic voice, willing to speak uncomfortable truths and to take on the enemies of the Republican Party at every turn. On the left, it was considered merely the latest demonstration that the 45-year-old is a slightly unhinged, paranoid fear-monger, determined to use lies and distortion to further her cause.

If the exact definition of what Palin does represent is probably somewhere in between both those extremes, what cannot be denied is the fact she's had the fastest rise to political stardom in recent American history. It took President Barack Obama 11 years to make the journey from the Illinois State Senate to the White House. In just 15 months, Palin has gone from being the unknown governor of a largely inconsequential state to becoming the best-known and, some would say, best-loved face of the Republican Party

Despite growing evidence the opposition may yet have to take a more moderate line to win back lost voters in 2012, Palin's popularity among the hardcore constituency was still evident in the run-up to last week's elections. Conservative candidates all across America sought out her endorsement, knowing such an imprimatur would impact on the faithful and, more importantly, on financial donors too.

When her memoir Going Rogue: An American Life is published this Tuesday and turns into an instant best-seller, the book will offer one more barometer of her enduring influence and plenty more material to her opponents.

The latter two points are directly related. The more the critics dismiss Palin as some sort of distaff George Bush who once governed a state that's really just a national park (which still gives her far more executive experience than Obama, ahem), the more passionate her followers become. Every time the left pile on, deriding her as clueless, ignorant, and backward, just to give a sample of the critiques, it merely enhances her status as the darling of the right wing. There's nothing more endearing to politicos than the belief their leader is being unfairly persecuted by their enemies.

To a certain extent, they have a point too. Witness the way in which the American media treat Levi Johnston. For the remarkable feat of once dating and impregnating Palin's daughter Bristol, Johnston has become a national celebrity. Whether or not the 19-year-old follows through on his threat to pose nude for Playgirl, this high school drop-out has already stretched his 15 minutes of fame to a lucrative half an hour by constantly recycling titbits about the Palins in general, and the woman of the house in particular.

Scarcely a week goes by when some entertainment or news show doesn't parade him questioning her parenting and her public persona. Very often, these outlets don't seem too bothered about questioning the objectivity of an estranged teenager who's fighting a custody battle while also trying to make a living off his accidental notoriety. Hardly the most credible witness in the court of public opinion.

"If I really wanted to hurt Palin," said Johnston on CBS' The Early Show the other week, "I could, very easily, but I'm not going to do it, I'm not going that far."

Chivalrous stuff from a guy who's already accused her of crimes as diverse as never cooking for her kids, never cleaning the house, and calling her Down Syndrome baby Trig "the retarded one". It's all the more disturbing too because it's par for the course in much of the Palin coverage. Immediately after she was first nominated as John McCain's running mate last year, 400 Democratic Party operatives flooded Alaska in search of negative stories about her and leftist blogs began openly speculating Trig was not her son at all but her younger daughter's. Even Bill Clinton, at the height of the Monica Lewinsky madness, wasn't subjected to conjecture this tawdry.

Seedy as her trip through the tabloid wringer has been (false rumours of her impending divorce were all the rage this summer), it has undoubtedly contributed to Palin's continued rise and rise. Never mind the way in which she seemed to negatively impact on the presidential race, a feat that might well have sounded the death knell for another political career, the conservative rump of the Republican Party still can't get enough of her. Late-night comics can mock her as the woman who claimed to be able to see Russia from her house, supporters will prefer to see her as the feisty woman who mocked politically correct environmentalism by announcing she wanted to "Drill, baby drill" for domestic oil.

Throughout Obama's own campaign, and in particular during the primaries, it was constantly reported he possessed a rock-star quality that energised people. Well, among the sections of the American population that Obama once lambasted for clinging to "God and guns", Palin has the same giddy effect. They love her unconditionally. They don't care that journalists are upset she doesn't read news magazines or study foreign policy. They aren't bothered that she makes the odd embarrassing gaffe in interviews either.

To most of them, it's enough that she's attractive, and knows how to use a gun and how to gut a fish. These are not people who will be waiting for the New York Times review to come in before lining up to buy her book.

"In this eagerly anticipated memoir, Palin paints an intimate portrait of growing up in the wilds of Alaska; meeting her lifelong love; her decision to enter politics; the importance of faith and family; and the unique joys and trials of life as a high-profile working mother," says the jacket leaf. "She also opens up for the first time about the 2008 presidential race, providing a rare, mom's-eye view of high-stakes national politics—from patriots dedicated to 'Country First' to slick politicos bent on winning at any cost."

The marketing premise of the book appears to be her reputation as something of a maverick. Despite the election campaign going seriously awry, there survives this carefully cultivated image of Palin as an anti-Washington outsider taking her cues from the public rather than the lobbyists, a crusader always willing to take on the establishment, regardless of the personal cost.

A grand notion, it is rather undermined by the strange geography of the book's promotional tour. After appearing on tomorrow's Oprah (a hostile venue for a conservative or any unbeliever in the church of Obama), Palin is restricting her in-store signings to friendly territory, eschewing states and big cities with heavy Democratic leanings. No matter how you spin it, that's not the courageous action of somebody willing to take on the opposition on their own terms.

Perhaps she's right to be circumspect though because on Tuesday, another book with an uncannily similar cover design, titled Going Rouge: An American Nightmare will also hit the shelves. Compiled by the editors of the left-wing magazine The Nation, it's a collection of 23 essays about Palin from high-profile contributors like Naomi Klein. Among other topics, it will examine "the nightmarish prospect of her continuing to dominate the nation's political scene".

That they would go to such lengths to counter somebody the left likes to portray as of no real consequence seems to suggest they do secretly still regard her as some sort of a serious threat. After all, a heavyweight media outlet wouldn't be wasting all that time and resources on a politician with a great future behind her. Would they?