Fifty years ago, on the morning of October 16, 1962, the CIA delivered to John F Kennedy aerial reconnaissance photos revealing Soviet missile sites in Cuba.
Shortly after the CIA briefing, Kennedy showed the photos to his advisor Kenneth O'Donnell.
The president was alarmed. ''You'd better believe it,'' he told O'Donnell, coming to terms with the missiles' significance. ''We've just elected Capehart in Indiana and Ken Keating will probably be the next president of the United States''.
The Cuban Missile Crisis has become an icon of 20th century history: the closest the Cold War came to a hot war, two great superpowers playing a game of brinkmanship that could have slipped into Armageddon.
But it was more a domestic crisis than a foreign policy crisis. Fear of the November 1962 mid-term elections loomed larger than fear of nuclear war.
There's a lot of mythology about those 13 days in October. It didn't take long for the tale of an heroic president pulling the world back from the precipice to take root. But that mythology massively overstates the severity of the Cuban Missile Crisis, and, as a consequence, the likelihood of apocalyptic nuclear war at any time in the 20th century.
Put simply, the world never came to ''the brink''.
In his excellent 2010 book, Atomic Obsessions, the political scientist John Mueller demonstrates neither Kennedy nor Nikita Khrushchev had any intention of escalating to nuclear hostilities.
The Soviet premier, for all his bluster, was scarred by his experience of World War II. One of the cables he sent Kennedy wrote of his fear of the ''death and destruction'' of total war. Explaining himself later, Khrushchev said ''I'm not a Czarist officer who has to kill himself if I fart at a masked ball. It's better to back down than to go to war.''
It's now clear Khrushchev placed the missiles in Cuba to deter an American invasion — that is, not in an offensive capacity. But even then, some historians have suggested there was agreement in the Soviet leadership to withdraw the weapons if the US responded with military force.
The USSR never even went on a general alert.
The Americans were even less eager for conflict. Put aside the warmongering General Curtis LeMay, who was nowhere near the decision-making team and exasperated Kennedy. David Welch and James Blight, two historians who have worked closest with the tapes of White House meetings, say the odds the Americans would have escalated hostilities were ''next to zero''.
And the gambit that ended the crisis — Kennedy's secret promise to Khrushchev that he would remove American missiles from Turkey — wasn't much of a gambit at all. The tapes reveal the president vowing ''I don't want to go to war anyhow, but I am certainly not going to war over worthless missiles in Turkey''.
Keeping the deal secret was just good domestic politics.
Of course, neither side knew of the other's true position. But half a dozen times during October each side made missteps which, had the world been truly on the brink, would have pushed them off. A U-2 was shot down trying to get a closer look at the missile sites. Neither superpower budged. Another U-2 strayed into Russian territory and was chased out by Soviet fighters. Neither superpower budged.
Nobody wanted war. And as Henry Kissinger once said, ''despite popular myths, large military units do not fight by accident.''
So what was the crisis in the Cuban Missile Crisis?
As usual, domestic politics drove foreign policy.
Kennedy had beaten Richard Nixon in 1960 by outflanking him as a hawk — charging that the Republicans had no plan to topple Fidel Castro and stoking fears of Soviet nuclear superiority.
But after the 1961 Bay of Pigs debacle — where US backed Cuban exiles were routed in an invasion attempt — Cuba suddenly became Kennedy's political problem. Cuba looked like it was going to be a big issue in November, and maybe even in the 1964 presidential race.
Two Republican senators in particular attacked him furiously over Cuba: Ken Keating, a New Yorker with White House ambitions, and Homer Capehart, from Indiana.
These attacks had hurt. Kennedy wanted to reassert his hawkish credentials. The most fateful event of the Cuban Missile Crisis occurred, not in October, but in a press conference a month earlier. On September 13 Kennedy declared bombastically that ''if Cuba should possess a capacity to carry out offensive action against the United States ... the United States would act.''
Kennedy didn't know missiles were already on their way. This September ultimatum was for a domestic audience — to counter Republican claims he was soft on communism — but it seriously constrained his choices in October. He'd promised action.
Throughout the crisis, Kennedy regretted his September chest-beating: ''I should have said that we don't care''. But it was too late. He'd ruled diplomacy out. Blockading Cuba was the least warlike thing the administration could think of.
Kennedy famously declared on television that the missiles were an explicit threat to American security.
Privately however the administration thought different. ''It is generally agreed,'' said Kennedy's advisor Ted Sorensen on October 17, ''that these missiles, even when fully operational, do not significantly alter the balance of power — that is, they do not significantly increase the potential mega-tonnage capable of being unleashed on American soil.''
Defense secretary Robert McNamara was more direct. ''I don't think there is a military problem here.''
The successful resolution of the crisis on October 28 blunted the Republican attacks. The mid-term election was only a week away. The Democrats picked up four seats in the Senate, one of which was Homer Capehart's.
October 1962 has become central to the JFK mystique. It was quickly integrated into the legend of Camelot.
Not only that, but the episode defined how we think of nuclear politics; as if we are, at all times, minutes away from global war.
But if the Cuban Missile Crisis is the closest the world has ever come to a nuclear exchange, then we've never come very close at all.