They don't make them like Pamela Harriman anymore. On balance, that's probably a good thing. Not that there isn't much to admire or, at least, marvel at in the life of the mid-century paramour turned Democratic Party power broker -- her talent for keeping strategically chosen lovers as lifelong friends, her zest for reinventing herself, her unquenchable optimism about her party's prospects, her capacity for leading a remarkably consequential public life without ever holding an actual public post, or even really a job, until she was seventy-three. But Harriman's path to power -- greased by aristocratic privilege, fuelled by sexual alliances, and, for both reasons, not exactly transparent -- isn't one you'd recommend to an ambitious woman today, either for her own sake or, not to sound too stuffy about it, for democracy's.

Sonia Purnell's new biography, "Kingmaker: Pamela Harriman's Astonishing Life of Power, Seduction, and Intrigue" (Viking), is a bit of a feminist reclamation project, bent on producing a more respectful portrait than those found in two earlier books, Christopher Ogden's "Life of the Party: The Biography of Pamela Digby Churchill Hayward Harriman" (1994) and Sally Bedell Smith's "Reflected Glory: The Life of Pamela Churchill Harriman" (1996). It's time to set to rights, Purnell believes, Harriman's reputation as, what she calls, a "conniving and ridiculous gold digger obsessed by sex." I wasn't entirely convinced that such a rescue operation was necessary. It's true that the earlier books were meaner than Purnell's, flecked with nineties snark and anonymous quotes. (Ogden's was the product of an authorized-biography agreement gone sour.) And Harriman was certainly subject to gossip, some of it scurrilous and sexist. A nasty takedown in The New Republic by the glib British expat Henry Fairlie, published in 1988 under the headline "Shamela," dubbed her a Washington widow of "vivid repute . . . her name inflated with each husband." When Bill Clinton nominated Harriman to be the Ambassador to France, Senator Strom Thurmond felt it appropriate to declare, "They're sending the Whore of Babylon to Paris!" (That would be the irredeemably segregationist senator from South Carolina, who had a string of sexual-harassment allegations to his name and a long-unacknowledged daughter by a Black teen-ager whose mother worked for his parents.)

As Purnell herself amply documents, however, Harriman's political savvy and clout weren't exactly overlooked in her lifetime. Clinton, whose Presidential promise Harriman recognized and championed early on, called her "the First Lady of the Democratic Party." When the Gorbachevs made a trip to Washington, in 1987, they sought her out. Nelson Mandela made a point of visiting her Georgetown home, in 1993, to tap her counsel on getting voters to the polls. When "Shamela" hit the stands, Purnell says, half the Senate signed a letter condemning the article (more than a few of the senators had been beneficiaries of her fund-raising largesse), adding that Harriman, "a woman of extraordinary wealth and ability," could have chosen a life of "idleness and self-indulgence" but, instead, had chosen one of "public service."

Purnell, the author of three previous biographies (including the excellent "A Woman of No Importance," about Virginia Hall, an American whose career as an Allied spy during the Second World War really was in need of rediscovery), has written a thorough account of Harriman's rise which also manages to be a brisk, twisty read. Harriman was a woman of action and, on the evidence presented here, a supremely confident, canny, seductive, driven, and discreet one. She was neither particularly introspective nor penetrating in her observations of others. (Purnell quotes Harriman describing her lover Gianni Agnelli, the chairman of Fiat, as "nice" and "fun"; of her second husband, the hot-shot talent agent turned Broadway producer Leland Hayward, she said, "There was something very vulnerable about [him] that attracted me enormously.") Informed of a diary kept by a formidable man of her acquaintance, the young Harriman burst out with a telling response: "Oh, what a goddam bore! Imagine! If something exciting happened during the day, the last thing you want to do is write it down." The action is plentiful, though, much of it bound up with the central plotlines of the times -- she was not a woman to "let her century pass her by," as Clinton's Secretary of State Madeleine Albright put it. And Purnell has found plenty of people to talk to about their memories of Harriman, along with archival sources, including newly available transcripts of interviews with her that Ogden, her spurned biographer, conducted.

Harriman was born Pamela Digby, in 1920, the oldest child of Edward Kenelm Digby, the eleventh Baron Digby, and the Honourable Constance Bruce. Being minor members of the peerage, they naturally needed nicknames: he was Kenny, and she was Pansy. Pamela spent part of her childhood in Australia, where Kenny had been dispatched as military secretary to the governor-general. Back in England, the Digbys lived at a family estate, Minterne, where they were waited upon by footmen who wore gold buttons engraved with ostriches, part of the family crest. Minterne sat on some fifteen hundred acres and contained fifty rooms but -- until Pamela's parents moved in -- no bathrooms, which Kenny's father had thought were "disgusting." Purnell tells us that Pansy "doted" on her spirited, rambunctious elder daughter, "almost as if she had been the desired son," though she "rarely ventured" to the nursery where Pamela and her sister spent most of their time. Kenny, like the blustering patriarch of another aristocratic family with intelligent daughters, the Mitfords, was firmly of the opinion that formal education rendered young women unmarriageable. As a teen-ager, Pamela pleaded to be sent to boarding school. When Kenny and Pansy relented, she spent less than two years at a private school for girls, in Hertfordshire, from which she departed with a certificate in domestic science, the capstone of her classroom education.

The Digbys did dispatch her to Paris and, oddly, to Munich -- in 1937, when Nazis were marching in the streets -- for the requisite finishing. Purnell notes that "droves of aristocratic girls like Pamela were sent to be immersed in Bavarian culture, which was considered more polished and disciplined than that of France." ("Disciplined" would be one word for it in those years.) Seventeen-year-old Pamela was both politically attuned and naïve enough to ask the nearest Mitford girl -- the Nazi-loving Unity -- to arrange a tea for her with Hitler. Her account of their meeting wasn't especially sharp ("he seemed made of tinfoil as later caricatures made out and he was sort of nervous"), and some of her detractors insisted that she must have made the whole thing up. Purnell doesn't think so: "However unsatisfactory, the meeting marked the start of Pamela's lifelong mission of self-education about politics and power."

Soon enough, it was time for Pamela's début, which is to say, the great push to marry her off to a suitable man of her social class, in the annual twelve-week marketplace ritual known as the season. Within a few years, she would secure her reputation as a world-class flirt and beauty -- auburn-haired, with scintillating blue eyes and a peaches-and-cream complexion, gifted in the art of making whichever man she happened to be speaking to feel like the only man in the room. She'd lean "forward to capture his every word," Purnell writes of one significant later conquest, stroking "his forearm with her fingertips," laughing "deliciously at his attempted repartee, her tongue pointed erotically behind her teeth." (That last trick is a little hard to picture, but I'll take Purnell's word for it.) Yet Pamela's first season was a flop. Deborah Mitford, who also came out that year, described her as "rather fat, fast and the butt of many teases." Nancy Mitford, the novelist, was hardly less withering, calling Pamela "a red headed, bouncing little thing, regarded as a joke by her contemporaries." (Love in a cold climate, indeed.) Pamela ended the season without a fiancé.

The man she said yes to the following year would transform the course of her life -- not through force of character (he had a weak one) or of love (theirs was not a moonstruck romance) but through the strength of his name and connections. Randolph Churchill, the only son of the future Prime Minister, "did not even pretend" to be in love with Pamela when he proposed -- he'd reportedly asked nine other women to marry him that week alone -- but he told her that she looked like a healthy candidate to bear his child, paternity being his Churchillian duty. As a husband, the philandering, gambling-mad, verbally abusive Randolph was a colossal letdown, starting with their wedding night, during which he read aloud great chunks of Edward Gibbon's "Decline and Fall of the Roman Empire." ("To ensure she was paying attention, between bouts of snoring or farting, he barked, 'What was the last sentence?' " Purnell writes.) But, as his father's son, he held a golden key. While her husband did his military duty in England and then in Egypt, she grew close to her in-laws, Winston and Clementine, who were utterly charmed by her. She sat up late with Winston, playing the two-handed card game bezique when he was too worried to sleep, cut his cigars for him, and took a deep interest in the progress of the war. By 1940, Pamela, now pregnant, had moved into 10 Downing Street, where she shared a bunk bed in the bomb shelter with the Prime Minister (she occupied the lower bunk, joking that she had "one Churchill on top of me and one inside me") and dined with senior government ministers and foreign leaders, including Charles de Gaulle. Warning that the Germans might soon invade England, her father-in-law told her that she would have to take down at least one, using a carving knife if necessary. In the event, the Churchills would find much more suitable uses for her talents.

Clementine, we're told in "Kingmaker," had "noticed Pamela's power over older men (including her own husband) through a rare cocktail of flattering attention, smoldering sex appeal and an impressive grasp of geopolitics." Now Clementine and Winston saw a chance to deploy their daughter-in-law in the all-important campaign of wooing the Americans to abandon neutrality and join the fight against Nazi Germany. In that cause, Pamela found her own distinctive war work, "unleashed as the Churchills' most willing and committed secret weapon." A 1941 photo spread in Life, shot by Cecil Beaton, of a winsome Pamela with her new baby boy, named for Winston, enhanced the appeal of the plucky English, holding out so bravely and attractively against the Blitz. But it was her deftly managed personal contacts that helped seal the Anglo-American special relationship. When Franklin Delano Roosevelt sent his irascible right-hand man, Harry Hopkins, to London, the Churchills launched a charm offensive in which Pamela was front and center. Then came an offer from Lord Beaverbrook, a press magnate whom the Prime Minister had appointed to oversee aircraft production. Beaverbrook would put baby Winston and a nanny up at his country estate so that an unencumbered Pamela could move into the Dorchester hotel, in London, and work her magic on influential Americans. He would outfit her for the mission, Purnell writes, with a wardrobe of "tight-fitting evening frocks, high heels and natty tailored suits to help her in her new role in Britain's desperate struggle to survive."

In March, 1941, F.D.R. signed the Lend-Lease Act, effectively ending American isolationism by opening up U.S. military aid to Britain. He sent W. Averell Harriman to London to oversee the program, and to report back on the British conduct of the war. Harriman, too, would require some tender persuasion, and Pamela, now barely in her twenties, was up for the job. He was forty-nine, vastly wealthy from his family's railroad fortune, and, as luck would have it, "absolutely marvelous-looking," in Pamela's estimation. At a dinner at the Dorchester soon after his arrival, Pamela, wearing "a skin-tight shoulderless gold lamé dress bought specially for the occasion by Beaverbrook" and dazzlingly conversant in matters military and political, made immediate headway. What she called "a very fortuitous" Luftwaffe bombing raid sent them dashing to Harriman's lower-floor quarters. Here, Purnell gets a little purple, but that must have been hard to resist: "While the building quivered from the worst raid in London to date and shrapnel rattled down onto the streets, Pamela lay naked in the arms of the man who might be able to bring the horror to an end." She soon moved in with Harriman, who was married but with a wife far away in New York and busy with her own extramarital pursuits.