Believe the Republicans, and a mortal threat faces the Land of the Free should, as seems ever more likely, the Democrats regain control of the House of Representatives next week. The threat comes heavily disguised in the persona of an elegant woman closer to 70 than 60 (though she doesn't look it) with a fondness for finely cut suits in pastel shades, and cheekbones to die for.
But do not be deceived, warn Republican TV spots, voter mailings and campaign leaflets across the 50 states of the union, as America's no-holds barred mid-term election campaign moves towards Tuesday's climax. Nancy Pelosi is trouble - a wild-eyed La Pasionaria from the city that for properly reared Republicans is the epitome of wanton liberalism.
Now even that might not greatly matter, were she not the Democratic leader in the House of Representatives. Should her party on 7 November make the net gain of 15 seats it needs for a majority, Pelosi would become Speaker, the first woman ever to hold the third ranking office in the Republic. And this exalted position, "two heart beats from the Presidency", would be entrusted to - not to put too fine a point on things - a tax-loving, gun-hating, gay-coddling, welfare queen-supporting, abortion-promoting, illegal immigrant-cosseting peacenik.
Republicans conjure up the vision of an America transformed into a giant Haight-Ashbury, the neighbourhood within Pelosi's San Francisco congressional district that was home of the 1960s hippie movement. If Ms Pelosi had her way, the country would lie defenceless before the terrorists. Vice-President Cheney mocks her "San Francisco values". John Hostettler, a Republican congressman struggling to hang on his seat in Indiana, tells voters she is seeking to advance "the whole homosexual agenda". The prospect of a Pelosi-run House, another top Republican contends, "is just plain scary". Unfortunately, the dragon-lady description has a couple of serious problems.
For one thing, it's not quite true. Yes, she represents a district that voted 85 per cent for John Kerry in 2004, based in what is probably the most Democratic city in the country apart from Washington DC. Yes, she voted against the Iraq war from the start (which it should be said, more than half the Republicans in Congress probably wish they now had done as well).
Yes, she is unarguably liberal, with a long record of fighting for abortion rights, for rolling back the Bush tax cuts, for providing welfare for legal immigrants, and for human rights. Even more important, however, she is an intensely disciplined politician, relentless in her pursuit of the one thing without which all political ideas are mere talk, and which the Democrats have barely tasted since Bill Clinton left office in January 2001. That thing is power.
"The Republican caricature of her is completely at odds with how she's seen out here," says John Arensmeyer, a San Francisco Democratic activist, says. "She's serious, highly regarded, maybe not a visionary, but very good at the political game. She's not ideological, but very pragmatic. For this city, she rates as a moderate."
The second problem is that the demonisation may be pointless. For, as poll after poll shows, Pelosi is simply not very well known - which makes it hard to align the projected image of her with the charming and rather glamorous woman she is in real life. One reason is that she appears relatively infrequently on television. Critics say because she is apt to come across as brittle and over-intense. The ads thus tend to show her looking angry and staring-eyed, often alongside Ted Kennedy and Hillary Clinton, long-standing Democratic bogeymen both, in similar rant mode. Nevertheless, as Pelosi told Newsweek recently, "Two-thirds of the public have absolutely no idea who I am, and I see that as a strength. This isn't about me. It's about Democrats." So who precisely is Nancy Pelosi?
First off, she is not a native San Franciscan. Pelosi absorbed politics with her mother's milk, but on the other side of America. Her father was Thomas D'Alesandro, congressman for, and then mayor of, Baltimore during the 1940s and 1950s. She grew up not in the intense, idiosyncratic and tribal politics with which her adopted city is identified, but amid the old-fashioned machine politics, of favours granted and favours called in, of the old East Coast cities.
Motherhood dominated the first part of her adult life - five children in the space of barely six years after her marriage to Paul Pelosi, a property investor whose $50m fortune makes his wife one of the 10 richest members of Congress. "An Italian-American, Roman Catholic mother and grandmother" is her preferred description of herself. "Am I going to have to use my Mother-of-Five voice?" she is apt to ask, if an audience's attention seems to be straying.
Only much later did she enter the business of politics in her own right, first at a state level, before winning election to Congress in 1987, at the age of 47. Some charged that Pelosi was a lightweight in a well-cut suit. But she rose fast, becoming minority whip, the second ranking position of the opposition Democrats, in 2001. After Dick Gephardt stepped down as minority leader in November 2002 to launch a White House bid, she was overwhelmingly chosen by her colleagues to replace him.
That alone was achievement enough, making Pelosi the first ever woman to lead either party in either chamber on Capitol Hill. She is quietly but intensely proud of what she has achieved for her sex. In the male-dominated universe of politics, she had broken through not a glass ceiling, but a veritable marble ceiling. Now she stands on the brink of being "Madam Speaker". And if a Madam Speaker, why not a woman president?
But that remains a matter of conjecture. What is indisputable is the change she has already wrought in the way Democrats do business in the House - not in terms of ideas, but in a new hard-edged approach to the daily political battle. Every Republican attack must now be instantly rebutted.
She has also stamped down hard on bickering and party splits, using the award of plum jobs to cement her authority. Measured by their voting record, House Democrats are more united than in half a century. That trend seems likely to continue if she becomes Speaker, with chairmanships and other coveted committee jobs in her gift. Pelosi may have nice looks (rumours of face-lifts are utterly unfounded, she insists), but she has a ruthless streak as well. As she told CBS's 60 Minutes last month, in a rare prime-time television appearance, "I am very strong. I am tough."
She is also hugely energetic and intensely disciplined. With no need to worry about her home base, she has been on the road constantly during the campaign, visiting different states every day, raising money and making personal appearances for Democratic candidates in close seats across the country. One moment it is a closed-door meeting for donors, the next a gumbooted visit to a farm in rural Minnesota daintily wolfing down - if such a thing is possible - pork chops on a stick ("Oh, this is dee-licious").
But come next January when, if the polls are right, Nancy Pelosi is installed as Speaker of the 110th Congress, the truly serious business begins. And then we will gain a first answer to the most searching question of all. Can this woman who has reached that high office thanks to her relentless opposition to President Bush and all things Republican make her hyper-partisan and dysfunctional part of Congress work?
Ms Pelosi will take the helm of an institution with an approval rating of just 25 per cent, less popular even than President Bush. She promises she will extend a hand of reconciliation to a Republican minority, by allowing it for instance to submit its own amendments on bills, something long denied to her Democratic minority.
But is such generosity of spirit likely, given the understandable desire of Democrats to avenge a decade of being trampled upon, and the intense pressure on Pelosi to subject this White House to the tough congressional investigation of Iraq, Hurricane Katrina and the like that it has hitherto escaped? The Speaker-in-waiting, however, is a realist.
Barring a landslide, any Democratic majority will be small. She knows full well that if her party, entrusted at last with responsibility for governing, makes a mess of it, the chances of a Democrat taking the supreme prize in 2008 could be damaged. For that reason she has virtually ruled out a move to impeach President Bush, as demanded by some on the left. "It's off the table, a waste of time," she told 60 Minutes.
But the relationship between a driven liberal Speaker and a dogmatic, unbending conservative President is one of Washington's most fascinating unknowns. Pelosi has called Bush an incompetent and a liar. "He wonders what went wrong in Iraq," she says. "I hope he'll look in the mirror for starters." These are personal attacks, and no one sees politics through a more personal prism than George Bush.
Maybe these two political warriors can make an uneasy truce. After all, she argues, "we're both professionals. You could go through a long list of things his surrogates have said about me. I have a thick skin. They have to do what they have to do. I have to do what I have to do." On this slender glimmer of pragmatism depends a semblance of good governance in the first two years of Speaker Pelosi, and the final two years of rule by Bush.
A Life in Brief
BORN: Nancy Patricia D'Alesandro on 26 March 1940, in Baltimore Maryland, the youngest daughter of Thomas and Annunciata D'Alesandro.
FAMILY: Married Paul Pelosi, a native San Franciscan, in 1963. They have four daughters and a son.
EDUCATION: Trinity College (now Trinity Washington University) in Washington DC.
CAREER: Chairman, Northern California Democratic Party 1977-1981; chairman, California state Democratic party 1981-1983. Elected to Congress 1987 for California's 8th District, covering most of the city of San Francisco. Elected Democratic minority whip 2001, minority leader 2002.
SHE SAYS: "The emperor has no clothes. When are people going to face the reality? Pull this curtain back." - about George Bush
THEY SAY: "I think she helps our cause ... because of what she believes. Nancy is not in sync with a vast majority of the American people." - Vice President Dick Cheney