Some of the most consequential changes come upon us silently, almost without notice. The world is in the midst of one right now: Our doctrines of nuclear deterrence are obsolete and in desperate need of an update.
Some history: One of the most famous early concepts in deterrence theory was the doctrine of “Mutual Assured Destruction,” or MAD. Its logic was laid out by Thomas Schelling (a former doctoral advisor of mine), who won a Nobel Prize in economics in large part for his ideas on nuclear strategy.
The MAD doctrine is easy to explain: If they destroy us with nukes, we destroy them, thus creating a form of deterrence.
Sometimes Schelling is portrayed as an advocate of MAD. But he had an uneasy relationship with the doctrine. The basic dilemma was simple: Say the Soviets launched their nukes at the U.S. during the Cold War. Would a U.S. president have made the situation worse by destroying the Soviet Union in response? That would have shifted the final outcome from “Much of North America is destroyed” to “Much of North America and Europe is destroyed, and the resulting nuclear winter is much worse.” If Britain and France retaliated with their nukes — or if China, India and others entered the conflict — it would have been even worse.
Given that the U.S. loses that war no matter what, would it have retaliated in such a situation? To bring the question to the present day: Would the U.S. retaliate with a huge missile launch against a full nuclear attack?
Maybe. Or perhaps probably. But does anyone know for sure?
All it takes is one nuclear-armed maniac to decide the U.S. is not credible about retaliation in such situations. However unlikely that scenario may be, MAD has to fail only once to be an utter disaster. Or perhaps the nuclear-armed maniac is the president of the United States (or a nuclear submarine commander), striking unilaterally at a major enemy, expecting no retaliation.
The 1964 movie “Dr. Strangelove” features a Soviet doomsday device programmed to retaliate automatically if it detects an incoming attack, thereby institutionalizing MAD. A problem arises when a deranged U.S. general orders a plane to stage a nuclear attack against the Soviet Union, causing the movie’s protagonists to race to prevent catastrophe. Matters do not end well. Thomas Schelling was an adviser to that movie. It’s safe to say that, in the long run, he understood MAD was an unstable solution.
Another problem with MAD was the risk of a data accident. Stanislav Petrov, a Soviet air defense commander, in 1983 disobeyed orders and refused to launch a retaliatory nuclear strike against the U.S. It turned out that the supposed American attack was a Soviet data error, and Petrov possibly saved the world from destruction. Good for him — but such episodes have made it harder to feel good about MAD, which relies on human accuracy and judgment.
In the immediate postwar era, following the bombs dropped on Hiroshima and Nagasaki, it was commonly believed that another world war would follow a nuclear one. Since the 1960s, nuclear weapons have largely receded from the public consciousness. Nonetheless, nuclear war was very much a “thinkable” concept, however horrible it might have been.
Gradually, the use of nuclear weapons shifted into the “unthinkable” category. The longer the time since the actual use of nuclear weapons, the stronger the norms against the use of nuclear weapons. The decision to use them came to be seen as a choice that would upset everything about the international world order. Even a “dirty bomb,” which might not kill a lot of people, was morally classified as unthinkable — although potentially deadlier raids with conventional bombs were not.
Following the 9/11 attacks, an earlier generation might have expected the U.S. to use at least tactical nuclear weapons against al Qaeda in Afghanistan. But the U.S. did nothing of the sort, not wanting to upset the well-established norm. Did the U.S. really want a world in which it would be acceptable for Russia to use tactical nukes in, say, Chechnya? Schelling himself, in his remarks and presentations, increasingly stressed the importance of norms in thinking about nuclear weapons regulation.
Thus the world moved almost imperceptibly toward an approach to nuclear deterrence that was fundamentally different from MAD. The MAD doctrine is based on fear. The norms doctrine is rooted in a kind of complacency — namely, the expectation that any state with nuclear weapons has a meaningful stake in the world order. MAD is a doctrine of perceived insecurity. The norms doctrine is one of perceived security.
From the vantage point of 2022, it is clear that the norms doctrine, while it served useful functions for decades — just as did the MAD doctrine — has its limitations. The most obvious is that norms tend to weaken and eventually collapse.
Once the use of nuclear weapons became classified as “unthinkable,” political actors tried to extend that designation to other kinds of weapons. In doing so, they weakened the concept of unthinkability. The broader category of “weapons of mass destruction,” for example, was also supposed to be unthinkable. Yet Iraqi leader Saddam Hussein used them against Iran in the Iran-Iraq war of the 1980s. This led some countries to support Iran, but Saddam remained in power until former President George W. Bush led the war against Iraq roughly two decades later.
In 2012, former President Barack Obama told Russian President Vladimir Putin that they should agree that chemical weapons should not be deployed in Syria, as that would constitute a “red line.” Syria went ahead and used them, and there was no major kinetic U.S. military response, thereby erasing that red line and possibly others.
The pattern is evident: Once the category of “unthinkable” weapons is created, it is expanded so much that it loses its credibility. Politicians tend to spend down the reputational capital that their predecessors build up.
Another problem with the norms doctrine is that, sooner or later, there is value in breaking a norm — precisely because the norm was successful.
Think back to your high school. Your teachers probably set up behavioral norms that most everyone followed. That left room for a rebel who dared to defy those norms, if only for attention and to signal non-conformity.
With nuclear weapons, it’s not as if Putin or some other political “rebel” would use a bomb to make a point or to seem cool. Rather, Putin has been finding it useful to threaten the West and NATO with possible nuclear weapons use. If enough scary threats are issued, the use of nuclear weapons no longer seems unthinkable. And as the unthinkability norm erodes, eventually someone — Putin or not — may use nukes.
Finally, as mentioned above, the norms doctrine assumed the major nuclear powers all had a stake in a status quo. The Soviets made trouble in Nicaragua and other places, for example, but at the end of the day, they were not looking to overturn the entire apple cart. That won’t always be the case. Some leaders may seek to overturn or at least revise that world order.
These days there is the risk that Putin, facing defeat in Ukraine and an untenable situation domestically, might entertain the use of nuclear weapons to change what is otherwise an impossible dynamic. In such a scenario he would have no stake in the ex ante status quo, since that would be unlikely to allow him to die peacefully in his sleep.
The new doctrine in such situations may best be described as “Escalate to de-escalate.” Imagine Putin using a tactical nuclear weapon out of desperation, perhaps in the hope that some of the coalition against him will collapse or weaken. In that case the deployment would be followed by a dictate to negotiate on terms more favorable to Russia. Putin might think the use of nuclear weapons would give him at least some chance to escape his “impossible” situation.
This isn’t panicky doomsaying. Some Kremlin insiders say they share the fear voiced by the CIA, which recently suggested that Putin may be tempted to use small nuclear weapons. Such talk, even if accurate, further normalizes the notion that the use of nuclear weapons is not unthinkable after all.
The ongoing evolution of both nuclear and conventional weapons further blurs the distinction between the two and undercuts the notion that nuclear weapons are somehow special. On the one hand, conventional weapons are becoming more powerful. On the other, “battlefield nukes” can be more precisely targeted and therefore less generally destructive. A lot of the rest of the world — especially parts that have been bombed from the air or otherwise attacked — has already stopped seeing nuclear weapons as so special. As the Cold War recedes from memory, that trend is likely to continue.
Israel, an assumed but unacknowledged nuclear power, is in many ways a leading indicator of warfare trends, and it offers yet another example of how nuclear deterrence is evolving. Two developments are worth noting, both extensions of earlier trends but nonetheless reaching new extremes.
The first might be called “warfare by any other name.” For instance, since 2017 Israel has carried out more than 400 airstrikes, typically directed at Iranian or Iranian-supported forces in Syria, with some in Lebanon and Iraq. It also seems true that Israel has used drones to carry out strikes within Iran, and Iran sometimes retaliates (it sent missiles to take out Mossad offices in Iraq, for instance).
These mutual attacks have become institutionalized on both sides. Israel is even reputed to have a hotline with Russia to ensure that Israeli attacks in Syria do not kill Russian troops.
These attacks are not typically big news in the U.S., and no one (yet?) goes around saying that Israel is openly at war with Iran. Yet arguably Israel is openly at war with Iran — it’s just that no one says so too loudly.
Countries seem increasingly able to classify attacks as intermediate events of less than full urgency, avoiding the need for a major immediate escalation of deterrence. The U.S., Russia and Russia-affiliated agents have led many thousands of cyberattacks against one another, for example, which is a kind of war. Yet the important point is that no one regards these attacks as literal acts of war.
Such an ability to look the other way is useful in the moment. But over time, is it stable? The risk is that quite a few countries are de facto at war with each other, yet no one ever quite admits it, and so those conflicts continue and escalate slowly. It seems naïve to believe they will remain contained forever — and the gradual nature of the escalation may render it all the more likely.
The second Israeli development is Prime Minister Naftali Bennett’s announcement of Israel’s new “Iron Beam” system, which is supposed to use lasers to knock down incoming drones. Bennett notes the system has been successfully tested, though it remains an open question how far it is from being practically meaningful. Still, if better defenses against drones are possible, then they are also possible against missiles — and they will change the calculus of nuclear deterrence.
If you can rapidly vaporize the missiles headed your way, a first strike, nuclear or otherwise, becomes thinkable once again. The forthcoming retaliation from your enemy might not penetrate your defenses enough to destroy you. Even if these defensive systems are years away, the countries lagging in this technology race will see them coming, and they may decide to engage in their preferred military actions sooner rather than later. Why wait until the odds have turned against you?
In other words: Better defenses, which are inevitable, will start the problem of nuclear deterrence all over again.
The lessons of these developments, taken as a whole, are disturbing. We used to think of nuclear deterrence as a problem that, once all major countries had enough weapons to kill each other many times over, had been solved. That was wrong. Any doctrine of nuclear deterrence is set in a particular political and social context and is relative to a particular set of expectations. As it turns out, each generation needs to reinvent successful nuclear deterrence for itself.
Are we up to the task? Is it even on anyone’s political agenda? We will find out, I suspect, soon enough. —Bloomberg