When Robert McNamara in 1995 finally gave liberal America what it had wanted for so long — a mea culpa on Vietnam, in his memoirs — he might have thought he would receive at least grudging acknowledgement that he had finally acceded to the views so forcefully put by opponents of the war 30 years before.

Instead, he received a mauling. The house organ of American liberalism, The New York Times, demanded that he not escape “lasting moral condemnation” despite his “prime-time apology and stale tears, three decades late.” The wounds of the sixties had, evidently, not yet healed.

McNamara’s only solace should have been that ultimately he wasn’t the real target of wrath of his fellow progressives. The man at whom that vitriol was really directed had been dead for more than twenty years. Lyndon Johnson barely survived four years after leaving the White House. It was Johnson, the great liberal legislator and true heir to FDR, whom liberals despised most for the war — until, that is, Richard Nixon usurped his mantle as bogeyman.

The Vietnam debacle, not to mention the sixties more broadly, were shaped by the peculiar coincidence that America was led, in turn, by three of the most brilliant and psychologically flawed men ever to inhabit the White House. It was the first of those, John F. Kennedy, foreign policy autodidact and long-term s-x and painkiller addict, who recruited McNamara from Ford Motor to become his Defence Secretary.

McNamara was the ultimate Kennedy-era whizkid, the “best and the brightest” selected by the new, young President to bring a more technocratic approach to solving American’s problems. McNamara, in his early forties and scary-smart, a systems design genius who had worked on bombing campaigns during WW2 with Curtis Le May and brought Ford back from the brink of ruin, wrought significant changes to the US military. He and Kennedy were horrified at the inflexibility of the US military machine, which seemed to have limited capacity to adjust between brushfire wars and nuclear annihilation.

They were also every bit as hawkish as their Republican predecessors, especially when Kennedy was egged on by his chief spearcarrier, his deeply unpleasant brother Bobby, on issues like Cuba. The Kennedy brothers plotted to murder Castro and it still remains unclear whether that was one of the factors in JFK’s death.

Many of Kennedy’s advisers couldn’t accept LBJ, the President from the Id, an outlandish character so implausible only real life could have created him. The Kennedy circle retreated to Georgetown and plotted a restoration over cocktails and touch football at Bobby’s. But some, like Mac Bundy and Dean Rusk — who never liked Kennedy — found serving under LBJ more to their liking.

McNamara spent four years torn between the two. Johnson always suspected him of having one foot in Georgetown and being in league with the hated Bobby, but nonetheless relied heavily on him as the US presence in Vietnam evolved first into a bombing campaign, and then into actual combat.

Much has been made of McNamara’s own growing disillusionment with the winnability of the conflict, culminating in his 1967 advice to LBJ to find a way out. It’s not entirely as clear-cut as that.

For a start, Johnson always understood victory would be immensely difficult, even if his Secretary of Defense could always find data to show that things were turning around. As early as February 1965, Johnson was telling McNamara — who has just finished explaining his own ambivalence about a request for combat troops to guard USAF bases as Rolling Thunder gets underway — that he didn’t think the war could be won (an excerpt from Michael Beschloss’s Reaching for Glory is here). This early acknowledgement of the difficulties of the conflict is taken by liberals as evidence of the implacable determination of Johnson to continue to waste American and Vietnamese lives without purpose, but that fails to comprehend Johnson’s own despair at the political unviability of withdrawal while maintaining support for his massive domestic social agenda, including on civil rights.

While Johnson found life without politics impossible, sinking into depression and succumbing to the heart condition that almost killed him in the fifties, McNamara acted out his guilt over Vietnam for the rest of his life, throwing himself (he worked so hard that Johnson was genuinely concerned he’d “have another Forrestal”, Truman’s Defense Secretary who suicided) into an anti-poverty agenda as president of the World Bank. He also — much more rapidly than his change of heart on Vietnam — came to the view that nuclear weapons were futile, one of the reasons Paul Keating tapped him to be on his “Canberra Commission” on nuclear weapons in 1995.

But like the President with whom he formed such a peculiar relationship, his significant achievements in other areas were, and will always be, dwarfed by the monumental error of Vietnam, a war neither of them knew how to win or to escape.

It’s an injustice — but a small one compared to those perpetrated in the fields and towns of South East Asia.