“Ask not,” said President Kennedy as he rallied young Americans to volunteer for national service in his inaugural address, “what your country can do for you – ask what you can do for your country.” Kennedy had a stricter rule for the women in his life, as journalist Maureen Callahan reveals in her lacerating exposé: asking nothing in return, they were expected to do what their commander-in-chief required, which meant supplying him with sex whenever and wherever he fancied.

As a senator, JFK tried out his priapic power by impregnating a 15-year-old babysitter and positioning an aide beneath his desk to fellate him while he multitasked in his office. As president, he ushered White House secretaries upstairs after work for brief, brusque sessions of copulation and rewarded them with a post-coital snack of cheese puffs; at one lunchtime frolic in the basement swimming pool he instructed a young woman to orally relieve the tensions of a male crony and looked on in approval as she obeyed. His wife, Jackie, whom he infected with a smattering of venereal ailments, lamented that his assassination deprived her of the chance to vent her rage at him. Nevertheless, she embraced his naked body before it was placed in a casket at the Dallas hospital, bestowing a final, perhaps frosty kiss on his penis.

JFK’s conduct mimicked the tom-catting of his father, Joseph, who kept his wife, Rose, permanently pregnant while he took up with movie stars such as Gloria Swanson – whom he raped without bothering to introduce himself at their first meeting – and Marlene Dietrich. Not to be outdone, JFK shared Marilyn Monroe with his brother Bobby, his attorney general. Appointed ambassador to the UK in 1938, Joe declared democracy to be defunct and hailed Hitler’s new world order. He particularly admired Nazi eugenics, which weeded out human specimens he found “disgusting”, and he applied the sanitary theory to his own family. His daughter Rosemary seemed emotionally volatile and looked too chubby to appear in press photographs; deeming her a “defective product”, he had her lobotomised, which left her “functionally a two-year-old”. His wife was not consulted about the operation.

A “negative life force”, Callahan suggests, was passed down from Joe to his descendants. The promiscuous Kennedy men had scant liking for women; with no time for pleasure, they practised what Callahan calls “technical sex”, short-fused but excitingly risky because this was their way of both defying and flirting with death. During the showdown with Russia over Cuban missiles, JFK installed a nubile minion in his absent wife’s bedroom for amusement while he diced with “nuclear oblivion – a catastrophe of his own making”.

The same sense of existential danger elated JFK’s son John, a playboy princeling who loved to show off his genitalia after showering at the gym. Callahan argues that for John Jr “dying was a high”, an orgasmic thrill that he insisted on sharing with a female partner. “What a way to go,” he marvelled after almost killing a girlfriend when their kayak capsized. In 1999, he bullied his wife, Carolyn Bessette, and her sister into flying with him on a private plane he had not qualified to pilot; in bad weather he was baffled by the instrument panel, and all three died when the tiny Piper Saratoga spiralled into the ocean. The accident, in Callahan’s view, was “a murder-suicide”.

An angry sympathy for the women “broken, tormented, raped, murdered or left for dead” by the Kennedys inflames and sometimes envenoms Callahan’s writing. Her account of Rosemary’s unanaesthetised lobotomy left me reeling. It’s equally painful to read about the agony of Mary Jo Kopechne, who drowned in Ted Kennedy’s overturned car at Chappaquiddick in 1969 while he wandered off to arrange for a fixer to finesse press accounts of the calamity: upside down, she contorted her body for hours to gasp at a dwindling pocket of air. Carolyn Bessette tormented herself to qualify as a blond Kennedy consort, enduring a makeover that left her scalp scorched by bleach. In case cosmetic scars seem trivial, Callahan adds a terse allusion to the state of Bessette’s corpse, severed at the waist by her seatbelt in the plane that John Jr so air-headedly crashed.

After all this carnage, the book tries to conclude with a quietly triumphal coda. Liberated by the death of her second husband, Jackie Onassis took a low-paid job with a Manhattan publisher, which allows Callahan to imagine her anonymously merging with the crowd on her way to work, “just another New York woman on the go”. That, however, is not quite the end of the dynastic story. Jackie’s nephew Robert Kennedy Jr is a candidate for president in this November’s election, despite possessing a brain that he believes was partly eaten by a worm, a body that houses the so-called “lust demons” he inherited from his grandfather, and a marital history that gruesomely varies the family paradigm: the second of his three wives, in despair after reading a diary in which he tabulated his adulterous flings and awarded them points for performance, killed herself in 2012.

But the longest shadow is cast by Ted, promoted as the family’s presidential heir apparent in 1980 even though he was “the runt of the litter, kicked out of Harvard for cheating” and a flush-faced alcoholic into the bargain. A psychiatric assessment quoted by Callahan discerns in sloppy, greedy Ted a “narcissistic intemperance, a huge, babyish ego that must constantly be fed”. Sound familiar? That diagnosis makes Trump an honorary Kennedy, with Boris Johnson as a kissing cousin. I sniffed a further connection when Callahan describes Ted arriving drunk at a royal dinner in Brussels with an equally plastered sex worker as his date; the pair appalled the company with their intimate antics, which at one point included urinating on an antique sofa. Could this episode have been reimagined in Christopher Steele’s debunked 2016 dossier where, without evidence, Trump is said to have watched sex workers in a Moscow hotel defile a bed in which the Obamas had slept by drenching it in a golden shower?

Invented or not, such tales are fables about the pathology of politics. Forget the pretence of public service that these damaged men spout as they tout for votes. They seek electoral office because it licenses them to act out their fantasies – to randomly grab pussies or shoot passersby on Fifth Avenue with utter impunity. Having power over others makes up for their own quaking impotence, and all of us, not only those betrayed wives and disposable lovers, are their abused and casually obliterated victims.

• Ask Not: The Kennedys and the Women They Destroyed by Maureen Callahan is published by Mudlark (£25). To support the Guardian and Observer order your copy at guardianbookshop.com. Delivery charges may apply