Hiroshima, Nagasaki and the New Logic of Nuclear Deterrence

Hiroshima, Nagasaki and the New Logic of Nuclear Deterrence

Whether or not they ended the war, nuclear weapons changed the world. And they'll do so again.

Historians have decided that Japan’s surrender was not just about the A-bomb, and many people are taking this to mean that nuclear weapons are, after all, irrelevant. The historians may be right about the surrender, but the new conventional wisdom about nuclear deterrence is wrong.

A cottage industry has developed to puncture holes in the “myths” of nuclear deterrence. One particularly common theme is to argue, usually with exaggeration, that the Americans and Soviets may have been closer to thermonuclear war during the hair-raising 1962 Cuban Missile Crisis than was previously thought.

But perhaps no incident of the nuclear era has quite the same resonance as the U.S. dropping of atomic bombs on Japan in August 1945. For many years the argument that the clouds over Hiroshima and Nagasaki quickly ended the war has been a stock in trade of discussions over the role of nuclear weapons. Thus it is no surprise that here too there has been a pronounced shift in how many historians and analysts look at this seminal event. Gone is the untroubled assumption that the mighty power of the A-bomb turned Japan from a fanatically suicidal nation at war to one begging for surrender. Some scholars today argue instead that the bombs competed with the Soviet intervention in the war against Japan, the impending loss of Manchuria and the looming threat of American invasion in driving Tokyo’s decision to sue for peace. The atomic bombs were not, in this line of thought, the magic weapons that ended the war.

From this reassessment many people have taken a further step and drawn the lesson that nuclear weapons and nuclear deterrence just don’t really work as advertised—and thus that they can be dispensed with. As Ward Wilson, one of the most fervent advocates of this view, argues, “The collapse of the Hiroshima case undermines one of the cornerstones of nuclear deterrence theory.” This has become something like the conventional wisdom, highlighted in thoughtful retrospectives of the sixty-sixth anniversary of the bombing and The Atlantic’s recent assessment of President Obama’s nuclear-abolition vision.

The notion that Hiroshima shows that nuclear weapons aren’t all they’re cracked up to be rests on the argument, as Wilson puts it, “[t]hat the destruction of cities does not sway leaders…[and] that what happened in Hiroshima and Nagasaki was not overly remarkable.” Elsewhere he adds that, “the bombings of Hiroshima and Nagasaki merely extended what was already a ferocious campaign of city bombing and were generally within the parameters of destruction for these conventional attacks…[Also,] a close examination of diaries, letters, and official documents makes clear that the Soviet invasion touched off a crisis [in Japan], while the bombings of Hiroshima and Nagasaki did not.” As he summarizes, “The assertion that nuclear attacks are peculiarly effective because nuclear destruction is peculiarly horrible is unpersuasive.” In other words, Wilson argues, committed countries won’t give up even if they’re subjected to withering atomic attack. In fact, they might even be downright sanguine about it—burning down a country’s entire urban infrastructure, as the United States did to Japan, barely registers in people’s diaries, according to Wilson.

The trouble with all this is not that the reinterpretation of why Japan surrendered is wrong. In fact, it does seem that the Soviet entry into the war contributed substantially to Tokyo’s decision to surrender. The problem is the argument that nuclear weapons are irrelevant and can be dispensed with. If anything, the reverse: The logical implication of a really thoroughgoing assessment that nuclear weapons had little to do with Japan’s surrender is not that nuclear weapons are dispensable, but rather that they should be treated like any other weapon. For if the Japanese could withstand the near-total annihilation of their urban infrastructure and the dropping of two A-bombs, well then there truly is a lot of ruin in a nation. If you’re going to beat a nation like that, you’ll need to use every weapon available, which is why we haven’t gotten rid of rifles or precision-guided cruise missiles just because they aren’t war winners on their own. Thus, this argument would suggest, if Iran or North Korea gets into a fight with the United States or its allies, we had better use every weapon at our disposal because they and their leaders might well act like the Japanese.

This way of looking at things, though rarely heard now, has a distinguished pedigree. The influential U.S. Strategic Bombing Survey found after World War II that the massive bombings of Germany and Japan did not break their will to fight, and many prominent political and military leaders, even the eminently sane Ike, argued for treating nuclear weapons just like any other weapon.

This is where the logic would lead you if Wilson and company were right about the implications of Japan’s behavior. Fortunately for us, however, they’re not. The reason centers on the combined effect of the thermonuclear revolution and the fact of nuclear “plenty.” In the post-World War II world, nuclear weapons became immensely more powerful and vastly more common, particularly after the thermonuclear age was ushered in by the testing of the American H-Bomb in 1952. Thermonuclear weapons are at least an order of magnitude more destructive than the first-generation fission weapon dropped on Hiroshima on August 6, 1945. Moreover, there are now a large number of these weapons which can be delivered, at least by the United States, within hours against targets almost anywhere on the globe. This means that the nuclear arsenal of the United States, for example, is exponentially more destructive than it was in 1945.

Moreover, countries now know about the prompt destructiveness that nuclear weapons can deliver. They have seen what happened to Hiroshima and Nagasaki. Japanese leaders in August 1945 knew none of these things. Perhaps equally importantly, Tokyo’s decisionmakers did not know this in December of 1941, when they decided to go to war. If they had faced a United States which they knew would annihilate most of the country’s urban landscape and military power in a relatively short timeframe, would they have gone to war? It seems unlikely.

Finally, nuclear theologians have long noted the difference between what they call “deterrence” as against “compellence.” The insight is an intuitive one—threatening someone to convince him not to attack you is much more likely to work than threatening him in order to make him give up something he cares about. America’s objective in the summer of 1945 was essentially compellent—the attacks on Japan in August 1945 were part of an American effort to force Japan’s total rather than conditional surrender, a controversial objective even at the time. This sort of objective is invariably going to be harder to achieve.

So what, then, is the real lesson of Hiroshima and Nagasaki and the changing view of their role in Japan’s surrender? The real lesson is that nuclear deterrence is harder than many think. A normal person thinks about the gruesome and tremendous destruction that a nuclear weapon would wreak, and thinks—reasonably—that no one could court such a fate. But the bombings and their only partial effect on Tokyo’s leadership show that human beings, particularly powerful and ambitious ones with a lot to lose, can find themselves in strategic, political and psychological situations in which they are prepared to countenance weathering a nuclear attack and soldiering on. And their populaces, in these situations, might simply have no recourse.

But we needn’t despair, because, as the frigid peace of the Cold War shows, even in standoffs of enemies that simply hate each other, stability can emerge from the salutary fear of the absolute weapon. Nuclear weapons aren’t like other weapons. Used en masse, they are too destructive to be correlated with anything save vindication of a nation’s most vital interests. Thus they have changed the world, making it far more peaceful than the pulverized survivors of 1945 expected. But this means that stability and peace require not pooh-poohing the relevance or potency of nuclear weapons, but rather reminding our enemies and ourselves of their terrible power and of our willingness to harness that power to justified ends.

Elbridge Colby has served with the Office of the Secretary of Defense on the “New START” agreement negotiation and ratification effort and as an advisor to the Congressional Strategic Posture Commission. The views expressed here are his own.