One arena in which Bobby Kennedy had always shown his softer side was his faith. All the Kennedys called themselves Catholic, but Bobby practiced his religion in ways that endeared him to his mother and distinguished him from his brother Jack. During his three years at Portsmouth Priory School, he went to church the required four times a week plus the three optional services.
Ritual played an even bigger part of life in his and Ethel's home than it had in Rose and Joe's. The young couple outfitted each of the 13 bedrooms with a Bible, holy water and a crucifix or statue of Saint Mary. There were prayers every morning, before and after each meal, and at bedtime when the children assembled to recite as one "Now I lay me down to sleep".
Benediction was offered for the family too and as the list of deceased relatives grew, the children named each one and asked God to vault them straight to heaven. Also named were the saints they prayed to - Anthony to end poverty and find a parking place, Francis for the growing menagerie, and Christopher when they took off in a plane. Bobby's Saint Christopher medal never left his neck, which made sense given his non-stop travelling.
Most observers assumed Ethel was the keeper of the flame of faith, and that she was more wed to liturgy than Bobby. But the reassurance he found in his religion was apparent when, as a young man, he stepped over the railing and volunteered as an altar boy at St Francis Xavier Church in Hyannis, to the delight of his mother, who attended early Mass every morning.
He did the same thing in random cities across America during his many investigations and campaigns. "The priests couldn't believe the delicacy with which he did it," recalls advance man James Tolan. "They told me they never saw an individual serve Mass in that way other than a seminarian."
His Catholicism was integral to his politics, too. It reinforced the sense of public service drilled into the children by Rose and Joe. It was consistent with his commitment to the sanctity of the family - and to big ones like he was born into and that he and Ethel would more than replicate.
Bobby shared the Church's conscientious division of the world into good and evil, along with its judgment that communists are godless and the poor blessed. His life centred on three totems in those years of early adulthood: the Democratic Party, the Kennedy family and God.
But he distinguished between the faith's divinity and its hierarchy. While he held the former sacrosanct, he had always challenged Church authorities, from parish priests to the Pope.
Back in his undergraduate days, he joined other Harvard Catholics at lectures by Father Leonard Feeney, an influential Jesuit priest who warned that the Jews "are trying to take over this city" and preached that only Catholics could be saved. Bobby was embarrassed enough by those diatribes to discuss them with his brother Ted and his father, who arranged for him to meet Archbishop Cushing to convey his concern.
Even a Kennedy found it difficult to confront a prelate in those days and Bobby's courage likely played a role in Feeney's eventual expulsion from his order and excommunication from the Church.
In later years, Bobby lobbied the Pope to name a liberal replacement for New York's arch-conservative Cardinal Francis Joseph Spellman. And when he piled the children into the station wagon for the ride to church - they had to attend starting as toddlers, although they stayed in the back with a nursemaid until they were "church broke" - he "always carried a Bible with him", recalls Bobby Jnr.
"When the priest started talking about the Right-wing stuff, he would pointedly read the Bible, or he would read the Catholic newspapers at the back of the church." He called it "an awful thing" that the Church taught that babies, his or anyone's, were born in sin. He told his kids that "priests were Republicans and nuns Democrats". He also told them they needn't trust clerics to mediate the word of God when they could read it for themselves in the Old Testament and the New.
As defining as his faith was to him, Bobby's heritage was even more so, especially in distinguishing him from his brother the president. Their differences in temperament and outlook crystallised as the two spent more time together as young adults.
Jack would always be the handsome older brother, whose silky-smooth polish made begrudging Bostonians tag him as a "Fifth Avenue Catholic" and "Harvard Irishman". Bobby was all Gaelic, bristling with energy and trusting his gut.
If the Church had been their calling, Jack would have been pope, Bobby a parish priest. Jack looked past women he met unless they were young and gorgeous. Bobby was interested in nearly everybody, grasping a hand and peering into a face in ways that made a person feel a genuine connection.
Each stood as the other's best man when they married, but when Jack wanted to relax, he turned to his even younger brother Ted, not the more prudish Bobby. When Joe offered all his children $1,000 for not drinking until age 21 and another $1,000 for not smoking, Bobby collected, Jack indulged. "Jack has always been one to persuade people to do things," his father said. "Bobby tends to tell people what to do."
Their singularities were easy to spot on the American football field. Jack hung back, protecting his wounded back and aristocratic bearing, while Bobby charged into anyone, kids included, who was foolish enough to stand between him and the end zone. It was apparent, too, in the swimming pool.
Both made the Harvard team, where their acclaimed coach Harold Ulen remembered Bobby as "very heavy in the water", while Jack "could float very well". That, family biographers Peter Collier and David Horowitz write, was a metaphor for what separated the two: "Jack's sensibility was buoyantly literary; Bobby's was heavily moral, however inchoate. Bobby sought responsibility as compulsively as Jack tried to evade it."
Those very divergences let them construct a brotherly alliance that would become as celebrated in the political sphere as the one between Wilbur and Orville Wright in aviation. Each brother had trained for his role in their campaigns, Bobby by moulding himself into a relentless prosecutor, Jack by reading, travelling, and perfecting his smile.
The division of labour was perfect - Jack as statesman, Bobby as hatchet man - and perfectly suited to the Kennedy family business.
"It was politics that brought them together," Eunice said. "That's a business full of knives. Jack needed someone he could trust, someone who had loyalty to him. Jack knew he had a person like that with Bobby around."
The newspaper columnist Stewart Alsop called it a "sweet-and-sour brother act", in which "Jack uses his charm and waves the carrot, and then Bobby wades in with the stick". Theirs was a reversal of normal sibling roles, with the younger doing extraordinary things for the elder.
Bobby was his brother's keeper. Sometimes that role brought out his warm-heartedness, but it could also make Bobby defensive and vindictive. When Bobby told someone "No", Jack added "I'm sorry". Jack made friends, Bobby enemies - the appropriate outcomes for a politician and his sideman.
Yet those roles belied their characters in ways that elevated Jack and diminished Bobby.
"John Kennedy was a realist brilliantly disguised as a romantic, Robert a romantic stubbornly disguised as a realist," observed Arthur Schlesinger Jnr, biographer to both. Joe realised from the start that the yin-and-yang tandem could be unstoppable and Jack came to see that over time.
The Press called Bobby as steely as Joe, and Jack as tender as Rose, but they had it exactly backward. "Jack would cut you off at the knees," said Kenny O'Donnell. "Bobby would say, 'Why are we doing that to this guy?'" If Jack Kennedy was "the first Irish Brahmin", Massachusetts Governor Paul Dever observed after watching Bobby at work, "Bobby is the last Irish Puritan".
Larry Tye's Bobby Kennedy: The Making of a Liberal Icon is published by Random House, priced £25