Is there a taboo against the use of nuclear weapons? In other words, are people uncomfortable with the thought of using nuclear weapons in a way that cannot be explained purely through rationalist explanations? It seems the answer is quite clearly yes. After all, there have been many occasions throughout history in which a nuclear-armed state could have used nukes but chose not to. Israeli leaders, for example, had the ability to strike Egyptian troops in the Sinai during the Yom Kippur War. They did not. American forces could have employed nuclear weapons against China during the Korean War. Yet, despite pressure from the military, American civilian leadership chose to avoid nuclear escalation. In both cases, the nuclear-armed states would be conducting nuclear strikes against countries without a nuclear arsenal, thus obviating any concerns about mutually assured destruction. So, why didn’t they use their trump card?
According to Nina Tannenwald, part of the reason is the existence of a nuclear taboo. In her telling, there exists a normative prohibition against the use of nuclear weapons, which largely explains why no nuclear weapons have been used in combat since 1945. Unlike conventional weapons, nuclear weapons have developed a special status. As Calum Mattheson explains, “The Bomb” has achieved an almost mythical status that creates a morbid fascination but also partitions nuclear weapons from other aspects of the military arsenal. It seems intuitively correct that policymakers would be hesitant to unleash the destruction of nuclear weapons onto the world. Would you be willing to employ nuclear strikes as readily as conventional air strikes? I suspect the answer is no.
Nevertheless, I am relatively unconvinced of the durability of the nuclear taboo. First, there simply is not much empirical evidence that this taboo is widely shared around the world. There is also not much to suggest that a nuclear taboo exists among the American public (here is a more accessible writeup of the journal article). Now, the importance of public opinion in shaping elites’ views on nuclear use is not obvious. However, it stands to reason that more permissive public opinion would do nothing to constrain a president who might be considering the use of nuclear weapons. More generally, I think U.S. strategic culture still tends to mirror the Powell Doctrine (go big or don’t go at all), and this is reflected in the results of the Sagan Study hyperlinked above. When it comes to choosing between defeat and the use of nuclear weapons, it is not impossible to envision American policymakers opting for nuclear employment. After all, everyone, including the Americans, thought strategic bombing was a heinous war crime during the interwar period. As soon as the stakes were raised, though, and the U.S. found itself in a life or death struggle against fascism, American strategic bombers sortied over and over to reduce Germany and Japan to Schutt und Asche.
At least the U.S. is geographically secure, which means that it could likely survive a defeat without worrying about its existence. For nuclear-armed states like Israel and North Korea, however, this is not the case. If they lose, they are extinguished forever, and they thus face particularly intense pressures to use their nuclear weapons. The French Force de frappe was designed around a similar premise: if the Soviets overran Western Europe and the existence of the Republic was endangered, the French would unleash a massive nuclear strike against the USSR. French General Pierre Marie Gallois remarked that, “Making the most pessimistic assumptions, the French nuclear bombers could destroy ten Russian cities; and France is not a prize worthy of ten Russian cities.”
This raises another interesting question about the nuclear taboo: what if it is broken? Most taboos exist independent of an individual’s decision to violate them. For example, if you discover that your neighbor is a cannibal who regularly dines on human flesh, it is unlikely that you would suddenly expand your diet to include human organs. But it seems that this stickiness does not extend to the nuclear taboo. After all, if a nuclear-armed country finds itself on the receiving end of a nuclear attack, it seems highly unlikely that a taboo against nuclear use will prevent them from retaliating. Indeed, during a recent conflict simulation exercise in which I was a participant, there was not a single person who did not recommend escalation (potentially up to the nuclear level) against North Korea were it to detonate nuclear weapons against the U.S. or any of its regional allies.
That the potential use of nuclear weapons provokes discomfort is obvious. This is heartening, as it is one more impediment against the potential for nuclear escalation. Strategic balances and rationalist logics are important, but so are norms. Yet, we should not overstate the strength of the taboo. It seems neither particularly sturdy or, if violated, durable. We would do well, therefore, to continue developing ever more capable deterrent forces to ensure that a nuclear conflict does not occur.