How long have we known the truth about the Cuban missile crisis?

I "agree" with the reader cited below by James Fallows in his continuing series on threat inflation and ensuing U.S. military engagements:

I said that nearly all the major official "threats" of the modern era proved in retrospect to have been hyped. Missile gap, Tonkin Gulf, WMD, etc. Reader JA immediately replied, "You left out terrorism." And reader AS wrote:

It's true that we came close to nuclear war during the Cuban missile crisis. But according to a well documented article in the Atlantic [plus others],  the missiles themselves were an inflated threat, i.e., according to US generals at the time did not materially hurt US security and could easily be traded, as they eventually secretly were, for US missiles in Turkey. 

To elaborate a bit on the core point: the cited article, by Benjamin Schwarz, is based on a book by Kennedy Library vet Sheldon M. Stern, The Cuban Missile Crisis in American Memory, which is in turn based largely on secret tapes recorded by Kennedy that were made public in 1997.  Here is Stern on the absence of military threat posed by the missiles in Cuba:

Kennedy and his civilian advisers understood that the missiles in Cuba did not alter the strategic nuclear balance. Although Kennedy asserted in his October 22 televised address that the missiles were “an explicit threat to the peace and security of all the Americas,” he in fact appreciated, as he told the ExComm on the first day of the crisis, that “it doesn’t make any difference if you get blown up by an ICBM flying from the Soviet Union or one that was 90 miles away. Geography doesn’t mean that much.” America’s European allies, Kennedy continued, “will argue that taken at its worst the presence of these missiles really doesn’t change” the nuclear balance.

That the missiles were close to the United States was, as the president conceded, immaterial: the negligible difference in flight times between Soviet Union–based ICBMs and Cuba-based missiles wouldn’t change the consequences when the missiles hit their targets, and in any event, the flight times of Soviet SLBMs were already as short as or shorter than the flight times of the missiles in Cuba would be, because those weapons already lurked in submarines off the American coast (as of course did American SLBMs off the Soviet coast). Moreover, unlike Soviet ICBMs, the missiles in Cuba required several hours to be prepared for launch. Given the effectiveness of America’s aerial and satellite reconnaissance (amply demonstrated by the images of missiles in the U.S.S.R. and Cuba that they yielded), the U.S. almost certainly would have had far more time to detect and respond to an imminent Soviet missile strike from Cuba than to attacks from Soviet bombers, ICBMs, or SLBMs.

“A missile is a missile,” Secretary of Defense Robert McNamara asserted. “It makes no great difference whether you are killed by a missile from the Soviet Union or Cuba.”

Wow. Schwarz also demonstrates that the Soviets undertook to deploy the missiles in Cuba to offset U.S. "Jupiter" missiles pointed at the USSR in Turkey, and that the crisis was resolved by a secret missile-removal swap -- after the Kennedy administration risked nuclear war rather than agree to such a swap in public:

Beginning in the late 1980s, however, the opening of previously classified archives and the decision by a number of participants to finally tell the truth revealed that the crisis was indeed resolved by an explicit but concealed deal to remove both the Jupiter and the Cuban missiles. Kennedy in fact threatened to abrogate if the Soviets disclosed it. He did so for the same reasons that had largely engendered the crisis in the first place—domestic politics and the maintenance of America’s image as the indispensable nation. A declassified Soviet cable reveals that Robert Kennedy—whom the president assigned to work out the secret swap with the U.S.S.R.’s ambassador to Washington, Anatoly Dobrynin—insisted on returning to Dobrynin the formal Soviet letter affirming the agreement, explaining that the letter “could cause irreparable harm to my political career in the future.”

The funny thing is, while the evidence cited by Schwarz-via-Stern all derives from tapes and documents made public decades after the fact, I could swear that I remember reading substantially the same case in high school, circa 1976, in Stephen Ambrose's Rise to Globalism, published in 1971 (I'm sure about what I read in a very successful class on American foreign policy, but I may have the wrong book).  And now I am going to invest $15 in  a real-time memory test and download Ambrose's book on my Kindle.  Back in a few minutes! 

Update: the basic dynamic in this crisis -- that the U.S. would not publicly trade removal of its missiles in Turkey for removal of the missiles in Cuba but was happy to do so covertly -- was indeed plain when Ambrose wrote in 1971. I am quoting from an updated version but I believe this text is from the 1971 version; the sources, though unfootnoted, seem to be public statements made in the late 60s:

Far more important [than a letter from JFK to Khrushchev promising not to invade Cuba if the USSR removed the missiles], however, was an oral promise Robert Kennedy gave to the Soviet ambassador to the United States, Anatoly Dobrynin. Although the President would not back down in public on the Turkish missile sites, he evidently had begun to see the absurdity of the situation—the United States was on the verge of bombing a small nation with which it was not at war, and risking in the process a nuclear exchange with the Soviet Union, over the issue of obsolete missiles in Turkey that he had already ordered removed. Kennedy discussed the issues with his brother and asked him to talk to Dobrynin. On Saturday night, October 27, Dobrynin came to Robert Kennedy’s office. The Attorney General first presented the Russian ambassador with an ultimatum: If the United States did not have a commitment by the next day that the missiles would be removed, “we would remove them.” Dobrynin then asked what kind of a deal the United States was prepared to make. Kennedy summarized the letter that had just gone to Khrushchev, offering to trade the missiles for an American promise not to invade Cuba. Dobrynin turned to the sticking point—what about the American missiles in Turkey?

Robert Kennedy’s answer, as given in his own account of the crisis, was: “I said that there could be no quid pro quo or any arrangement made under this kind of threat or pressure, and that in the last analysis this was a decision that would have to be made by NATO. However, I said, President Kennedy had been anxious to remove those missiles from Turkey and Italy for a long period of time. He had ordered their removal some time ago, and it was our judgment that, within a short time after this crisis was over, those missiles would be gone.”

The statement was sufficient. The Russians had their promise. The next day Dobrynin informed Robert Kennedy that the Soviet missiles in Cuba would be withdrawn. The deal was done (Locations  2764-2777).

So it's not really true, as Schwarz asserts at the outset of his article, that everything we thought we knew about the Cuban missile crisis was wrong.  It was plain more or less from the start that the Kennedy administration brought the world within a whisker of war over a point of prestige.