Crossposted to The Good Blog 

Why did the US blockade Cuba after it discovered that nuclear missiles launch sites were being constructed there? I think the story most people have is that because the missiles were so close to the US it meant that suddenly the US was much more vulnerable to a nuclear attack than it had been previously. This meant that the US wanted to stop the rest of the supplies bound to Cuba on Soviet ships from reaching their destination. 
 

There is some truth to this story. But the real one I think points to one of the key events of 20th century history being deeply mysterious.
 

The strategic holy grail for country A during the cold war was for country A to attain a secure second strike capability while country B did not. This means that if B were to launch a nuclear strike on A, A would be able to respond above a threshold of destruction. However, the same does not for B - if A were to launch a first strike, B would either no longer have a nuclear deterrent or it would have a ‘small’ one. If both of these conditions are met, country A can launch a first strike to win a war. 
 

The balance of terror 

Surprisingly to me at least, in 1962 it was plausible that the US could launch a first strike and plausible that the leadership of both the US and USSR knew it. The most important reason for this was that the US dominated the USSR both in terms of number of ICMBs and the speed at which they could get them off the ground. The USSR had about 12 ICMBs whereas the US had hundreds and crucially because they were solid-fuel rather than liquid fuel they could get them off the ground within minutes whereas it took the fastest Soviet missiles 2 hours to launch. This was in the era when Soviet ICMBs were still stored in silos which couldn’t withstand multiple nuclear strikes meaning they were sitting ducks for US missiles. If the only missiles each side had to target one another were ICMBs then the US would have had a first strike capability no question.

However, by 1962 - by 1959 to be exact - both the US and USSR had all three legs of the nuclear triad operational. Although, for the Soviets, only just. I can’t find out how many long range bombers the USSR had in 1962. The best source I’ve found is a declassified US intelligence report from 1958 saying that the USSR had 85 long range bombers to the 1769 of the US. By 1959 the USSR had also deployed its first nuclear powered submarine capable of delivering nuclear missiles. The advantage of nuclear powered over diesel powered subs is that they’re both much quieter and can stay submerged for much much longer. Today having a single nuclear powered sub at sea is sufficient to have a secure second strike capability. However, it wasn’t until 1970 that the USSR developed a submarine that could carry a thermonuclear payload. This is very important to note - thermonuclear weapons a  different sort of weapon to a conventional nuclear bomb. The firebombing of Tokyo killed 100,000 people, substantially more than either of the atomic bombs dropped on Japan. Atomic bombs were viewed certainly in the early 50s as really really really destructive conventional weapon. It was thermonuclear bombs that changed nuclear weopons into a terrifying force whose use almost couldn’t be counteranced. In contrast to the Soviets, the US had already developed their Polaris submarines, which did carry thermonuclear bombs. 
 

A brief interlude in Berlin 

In some ways, the actual balance of power doesn’t matter for getting to the mystery of the missile crisis. What matters is how each side perceives the balance of power, and this is where the real mystery starts. The 1961 Berlin crisis was in many ways a dress rehearsal for Cuba with almost all the same actors on stage: Khrushchev, JFK and his brother and second in command Robert, the mercurial defence secretary Robert McNamara and the grizzled Chief of Staff of the Air force, General Curtis LeMay who commanded the bulk of American nuclear weapons. 

Berlin in 1961 was as totemic to JFK as Cuba would be in 1962 - keeping West Berlin out of the communist bloc was a line in the sand. In 1961, the Soviet Union attempted to turn West Berlin red. The USSR demanded a complete withdrawal of NATO forces from West Berlin, leaving it unable to defend itself if and when the USSR attempted to rid itself of the Capitalist stain. Publicly at least, the position was that the US was drastically behind the USSR in terms of ICBMs. The launch of Sputnik in 1957 had shown the world that the USSR had the ability to hit the US ICMBs in the Soviet union.
 

This, combined with Khrushchev’s claim that the USSR was producing ICBMs ‘like sausages’, general cold-war paranoia and 1957 Gaither Report meant that the US government believed that they were far behind the Soviet’s in missile production, and the Soviet leadership knew that Americans believed it. By 1961 - before the Berlin crisis - the truth about the dramatic US advantage was known in the highest US government circles, but this hadn’t been made public. During the Berlin crisis, with Soviet and US tanks eyeball to eyeball in West Berlin, the Americans made their knowledge of the true number of the Soviet missiles public. This, combined with the show of commitment to defending West Berlin, was enough to engender a Soviet climbdown from their ultimatum. 

Cuba

To set the scene, by the time the Kennedy administration knew that the Soviet planned to place medium range missiles in the Cuba there were already missiles ready to launch within 18 hours capable of wiping out any city in the South East of the United States, the President and executive committee (ex comm) knew it, the Soviet’s knew that they knew it, and both knew that more missiles were on the way. What the administration didn’t know, however, was that in addition to the city destroying strategic nuclear missiles there were also tactical missiles, which carried a much much smaller payload and were designed for battlefield use. 

We have extraordinarily good primary sources to give us insight into the administration's decision making because almost all of the meetings of ex comm, the joint chiefs of staff - the US military's highest body at the time - the discussions between JFK and his brother are recorded. From this we know a few things about how different key actors responded to the missiles in Cuba and at least what they said their reasoning was. 

General LeMay’s position was the clearest: the US should launch a full scale invasion of Cuba and to take the missiles and preferably unseat Castro for good measure. We have his explicit reasoning on tape. The US had a vast nuclear advantage over the Soviet Union, his bombers could get off the ground before Soviet missile’s could hit them and so the Soviet union wouldn’t do anything to stop them. It is worth mentioning however, that this was a man who considered that the US would have won a nuclear war if there were “two Americans and one Russian '' left. LeMay’s reasoning for why the US should invade Cuba anyway was that 

McNamara supported the blockade option - using the Navy to Cuba to prevent any more nuclear missiles from getting onto the Island. However, his reasoning is much less clear. We have him quoted as saying that being blown up with a missile from Cuba is the same as being blown up with one from the Soviet union. We also have him on the record as saying that the missiles in Cuba didn’t change the situation much - the US would still have a huge advantage. I think the inference that one should draw from this is that McNamara believed that the US and USSR had already reached strategic parity with one another, with the US retaining a numerical lead. This would mean that the US couldn’t launch a disarming first strike, while also meaning the Cuban missiles didn’t affect the strategic balance.

The strategic space
 

We have four options for what the effect of a full complement of Soviet on Cuba would have on strategic balance
 

1. The missiles maintained the status quo of the US having a first strike capability without meaningfully increasing Soviet power
    
2. US had first strike capability but the Soviets moved closer to eliminating it
    
3. The US lost first strike capability
    
4. The US didn't have first strike capability and so the missiles had no effect

I think the weight of evidence points to either 1) or 4) - the options which say that missiles had no strategic effect. And I think both the Kennedy administration and Khrushchev knew it. Just looking at the facts on the ground, the missiles were still liquid fueled and the US clearly knew where they were - this is what started the whole damn thing. This looks to me like the strategic situation shouldn’t have changed at all. The sheer number of ICMBs the US had in comparison to missiles that could cause damage to the US mainland means that if the US could be confident of being able to destroy Soviet forces capable of hitting the US, the relatively small number of extra missiles that would be stationed on Cuba shouldn’t change the balance - and the US would have conventional forces available to attack the Cuban missile sites. I think the key factor to realise here is the sheer speed advantage that the US had. The time between the decision to attack the missiles and their being destroyed is measured in 10s of minutes while the time to get the missiles off the ground is measured in hours. 

Now, it’s not at all clear that the US did have a first strike capability, but if the US decision to blockade Cuba, risking nuclear war, was based on the strategic effect of the missiles then this leaves the option that the missiles gave the USSR first strike capability. This just seems implausible. In addition to all the advantages I’ve laid out, the US also had missiles stationed in Turkey and Italy meaning that at best the missiles in Cuba put the Soviet union back at parity. 

So why the hell did the US blockade Cuba? And why did the USSR try (initially) to respond? 

I think it is possible that the missiles really did change the strategic calculus, or at least McNamara thought they did. Finding when he and civilians in the defence department thought that mutually assured destruction had been reached would confirm if this wasn’t the reason. But I think the reasoning of LeMay and most of the evidence we have for the reasoning of McNamara points in the opposite direction. This leaves JFK and Khrushchev to point us to what I think are the likely answers. 
 

Kennedy, Khrushchev and Cuba

“You had to do it Jack. They’d have impeached you”

“I think you’re right Bobby, I think they would have.”

The wonders of modern history is that we have access to the tape-recorded quotes above from Robert Kennedy talking to the President. I think this gives the most likely reason why JFK and the rest of excom couldn’t allow the missiles to stay in Cuba. It was simply unconscionable that the USSR could have missiles in America's backyard - in Cuba of all places! - after Khrushchev had committed that he wouldn’t put any missiles in Cuba.

 There’s a story about credible commitment in all this. If the US couldn’t show that it would defend it’s red lines then it would encourage the Soviet’s to take Berlin and potentially lead to the nightmare scenario of a salmari-invasion of Western Europe. There was discussion about the implications for Berlin in the excomm meetings and it was the explicit justification LeMay used, so it seems very likely that showing US resolve was a part of JFK’s decision making. But the general discussion doesn’t read to me like explicit considerations of strategy were the key deciding factor. No one in ex comm even proposed the option of just letting the Soviet’s keep the missiles there, an option that should have been on the table if the decision making was about carefully weighing up the costs and benefits of the chance of losing US credibility and Western Europe against the risk of nuclear war. The only man to suggest it was Adlai Stevenson, the US ambassador to the UN, and he was mocked as a coward. What seems most likely to me was that the motivation was some combination of desire to protect US credibility, hurt pride, and knowing that this would end any hope of Cuba being taken back from the communist camp and with it any hope of recovering from the humiliation of the failed bay of pigs invasion of Cuba. This concoction of humiliation would be unacceptable to the American voting public and congress and at best the Democrats would be wiped out in the midterms and at worst JFK would be, as his brother said, impeached. 

It would be nice for the arc of the story I’ve been telling if this post could end here, but I think I’d be remiss to leave Khrushchev out of the story because, from a strategic perspective it’s just as much a mystery as to why the Soviet’s risked nuclear war for no strategic advantage. 

Similarly to the US side, there is some chance that the conventional story is right, that the missiles gave the Soviets an assured second strike ability and were so strategically invaluable. I’ve read a lot less primary of the sources here, so to a degree I’ll just say that at least some historians do think that this was Khrushchev’s main motivation, although I think that just on an object level it seems to me unlikely to still stand. 

One of my favourite insane quotes is this one from Khrushchev as the crisis was beginning: 

“It’s been a long time since you could spank us like a little boy—now we can swat your ass”. Of course the Soviet Union could do no such thing - at best they reached marginal strategic parity with the US. What it speaks to is the feeling of being able to inflict the same humiliations the US had inflicted on the Soviet Union - the stationing of missiles in Turkey and West Berlin - back on the Imperialists. The scholarly consensus as far as I know is that Khrushchev decided on his plan at a meeting with the Bulgarian Premier, looking out across the black sea to where he knew US missiles were stationed so insultingly, terrifyingly, close to the motherland. The other subplot going on here was the Sino-Soviet split. A stable, Castro led Cuba would have been a triumph for Soviet camp, a first foray in the Western Hemisphere, which the US had adopted as home turf since the declaration of the Monroe doctrine. 

A punchline, of sorts

I think the key takeaway here is that there is a pretty high probability - it seems to me hard to argue that it’s below 25% or so, and very hard below 10% - that probably the most dangerous episode in human history was caused by not by the chess moves of great powers in a great game but by the fog and thunder of pride and fear. I have no clever policy solution to this, but I think the surprisingly unimportance of strategic fundamentals will be important to bear in mind when I write later posts about the events that caused the ebb and flow of the nuclear threat - I’m looking at you MIRVs - and is a core fact to bear in mind when thinking about how likely it is that Damocles’ sword that we all live under will fall.

 Edit:

I've learnt since writing this some more information about the beliefs of key actors during the crisis. The Joint Chiefs of Staff, excluding LeMay thought that the missiles would change the state of play significantly by allowing the Soviets to his bomber bases. An internal defence department report in response to this found that the US would still be left with 873 ICBMs , in addition to all of the Polaris submarines, giving the US more active nuclear missiles than France, the UK or China have today. Nevertheless I think this should provide a weak update towards thinking that strategic considerations were the most important factor.