During the 1962 Cuban Missile Crisis, famous movie director Stanley Kubrick decided to emigrate to Australia. He had read that the radioactive fallout from a nuclear exchange between the superpowers would be lowest in the remote city of Perth. However, when Kubrick, who had already ordered over 100 Boy Scout camp trunks for his voyage, learned that on the ship to Australia, two cabins would share one bathroom, he cancelled his trip. According to Jeremy Bernstein, who tells this anecdote in his book Nuclear Weapons, Kubrick’s fear of having to share a bathroom for six weeks with total strangers proved greater than his fear of dying in a nuclear inferno. The director stayed put—and dealt with his horror of nuclear war in his satirical masterpiece “Dr Strangelove, or: How I Learned to Stop Worrying and Love the Bomb.”
Today’s debate about deterrence displays even more contradictions than Kubrick’s emotional rollercoaster in the early 1960s. While much has been written about a “renaissance” of the concept of deterrence due to the deteriorating international security situation, the sad truth is that this renaissance has amounted to little more than slogans and preconceived notions. For the West, which is seeking to adapt its security policies to prevail against its autocratic challengers, this is a poor starting point.
The Changing Concept of Deterrence
According to Lawrence Freedman, the doyen of deterrence research in the United Kingdom, the concept of deterrence suits Western democracies very well. Deterrence strategies “appeal to governments because they can be presented as being defensive but not weak, and firm but not reckless.” Deterrence implies that undesirable developments can be kept at bay largely by remaining passive: The mere threat of force substitutes for its use. To be sure, the concept has its share of logical inconsistencies, and it also raises difficult ethical questions, in particular regarding its nuclear dimension. However, when it works, its benefits far outweigh its costs.
Since the beginning of the nuclear age, deterrence has become the object of scientific study. What was initially a purely military concept would be increasingly enriched by findings from political science, economics, and behavioral psychology. This led to a better understanding of the risks and limits of deterrence, but above all it highlighted the importance of the political-military context for determining the success or failure of the concept.
Even if the abstract-hypothetical nature of the subject at times produced questionable analyses, past decades saw the emergence of an impressive body of knowledge about the concept of deterrence, which sometimes served as guidelines for Western security policymakers.
After the end of the Cold War, deterrence played a less prominent role in the Western discourse on security, yet it gained again in importance as the international security landscape started to deteriorate, due to Russia’s increasingly aggressive behavior as well as the rise of an assertive China. However, the Western debate, especially since the Russian invasion of Ukraine in February 2022, demonstrates that many are prepared to ignore even the most basic principles of deterrence.
Understanding the Adversary’s Interests
One of the fundamental conditions for successful deterrence is to know the adversary’s interests. While such an analysis is difficult and speculative, in particular when it comes to opaque authoritarian states, it remains essential because it determines how deterrence needs to be organized.
However, the indispensable analytical diligence for such an exercise is often missing. Whether Russia or China, Iran or North Korea: In the context of the current deterrence debate, these states often become mere caricatures, seemingly pursuing only one goal, namely to make life for the West as difficult as possible. The notion that these countries might simply be pursuing their own—albeit highly problematic—security interests barely figures in the current debate.
The tendency to demonize one’s opponent is particularly visible in the highly emotional debate about the Russian assault on Ukraine. Russia is seen as a notorious imperialist whose expansionism can only be stopped by defeating it. Otherwise, so the argument goes, Moscow would be encouraged to sooner or later attack NATO as well. In this view, taken inter alia by the historian and commentator Anne Applebaum, Russia’s war against Ukraine is not a post-Soviet conflict, but the prelude to a much larger imperial project.
Such an interpretation of Russia and its policy has serious consequences for NATO’s deterrence strategy. If Russia were an opportunistic predator that will strike as soon as the West lowers its guard, peace in Europe would depend solely on NATO’s military strength. Worse, if even an alliance of 32 countries, which is massively superior to Russia, cannot deter Moscow from attacking it, one would have to conclude that Russia can no longer be deterred at all. Hence, an increase in NATO’s military capabilities, for which there are many good reasons, would not translate into a stronger deterrent. Instead, allied governments would have to prepare their citizens for an inevitable war.
This is precisely what many participants in the current debate are calling for. However, past experience from previous debates within the West indicates that measures taken by governments to strengthen deterrence will not always reassure their populations, but can also frighten them. Therefore, as British military historian Michael Howard argued already during the 1980s, deterrence and reassurance must always be weighed against each other. Years of debate about an imminent war will probably not lead to a greater willingness among Western populations to defend themselves, but may result in a crisis of security policy. Put differently, what may be intended to strengthen deterrence could, paradoxically, lead to its weakening and thus play into Russia’s hands.
The Limits of Deterrence
The attempt to assess the interests of the adversary is not only important for the defender in order to influence the potential attacker. One of the findings of deterrence research—albeit often ignored—is that the attacker, too, not only looks at defender’s military capabilities, but also his interests, as shown by Alexander L. George and Richard Smoke in their seminal work Deterrence in American Foreign Policy: Theory and Practice.
This explains why Argentina occupied the British-ruled Falkland Islands in 1982, even though Buenos Aires was well aware of the conventional military superiority (and nuclear status) of the United Kingdom. However, the Argentinian leadership believed that London’s interest in these islands was far too small to warrant recapturing them by way of a costly military operation in the South Atlantic. The Argentinian assessment of the British calculus turned out to be wrong, yet the UK’s deterrence strategy had failed as well, because London had inadequately communicated its continued interest in the islands.
This helps explain why the claim repeatedly made in the current debate, according to which a militarily stronger West could have deterred Russia from attacking Ukraine, reveals a fundamental misunderstanding of deterrence. It was easy for Russia to conclude that the West was not prepared to go to war for Ukraine. Consequently, NATO’s military superiority did not play a decisive role in Moscow’s calculus, as this superiority would not come into play in any case. Russia’s interest in preventing Ukraine’s westward orientation was always greater than the West’s interest in defending Ukraine militarily.
This asymmetry of interests ultimately proved more important than the military balance of power. Those who tend to ignore this connection between deterrence and interests risk being surprised, just like the UK in 1982 or NATO in 2022, irrespective of how much they are investing in their defense.
Nuclear Escalation Risks
The inadequate understanding of deterrence is not limited to the West alone. Russia also repeatedly fails to use the concept to advance its own interests. For example, even before its invasion of Ukraine, Russia was already reverting to a rhetoric of nuclear threats to limit Western support for Kyiv. These threats have been backed up by nuclear exercises and the possible deployment of nuclear weapons in neighboring Belarus.
However, it is obvious that these nuclear threats have not had the intended effect. This is because the West does not base its decisions solely on Russian statements or military capabilities, but also on its assessment of Russian interests. Just as Moscow came to the conclusion that the West would not defend Ukraine directly, the West concluded that the use of nuclear weapons would only be plausible if existential Russian interests were at stake. Since such a situation is still a long way off, an expansion of support for Ukraine—including by delivering longer-range weapons—is considered justifiable.
And there is more. By constantly referring to “red lines,” which the West crosses without consequences, Russia is undermining its own credibility and, at the same time, its deterrence. The image of determination that Moscow is trying to convey gives way to an image of helplessness, because the threat of weapons of mass destruction appears out of proportion to the political and military goals that Russia is pursuing with this war.
However, this could change if Western policy were to go beyond securing Ukraine’s survival and aimed to defeat Russia. Moscow’s nuclear threats would then take on a completely new dimension. One of the classic findings of behavioral psychology is that the fear of loss makes people take greater risks than the prospect of gain. In the context of deterrence, this means that one should not push a nuclear-armed opponent into a corner, i.e., into a situation where he believes he has nothing left to lose.
Self-Deterrence or Prudence?
It is precisely this realization that is guiding the West’s policy on Ukraine. Support for Kyiv is constantly being stepped up, yet without provoking a war between the West and Russia, which could potentially take on a nuclear dimension. It is obvious that this policy frustrates many observers, because it continues to deprive Ukraine of certain military options. Accordingly, some Western governments are accused of succumbing to their unfounded fear of Russian reprisals (“self-deterrence”).
It is quite possible that the West could have pursued a more resolute policy from the outset without provoking Russian retaliation. However, such a strategy would have considerably increased the risks for the West. For this reason, many countries, notably the United States, which bears the main burden of Western support for Ukraine, have opted for a more cautious course of action. Washington is also monitoring Russia’s nuclear activities and thus takes great care not to send any misleading signals.
For example, the US postponed a planned missile test shortly after the Russian invasion of Ukraine. However, the fact that conservative critics branded this rather unimportant decision as a sign of weakness showed that for some observers the urge to show strength and determination—ostensibly to improve deterrence—is pushing all other considerations into the background. If both sides acted according to this logic, a direct military confrontation would be almost inevitable.
Deterrence in the “Grey Zone”
The fact that the simple equation according to which more military strength equals greater deterrence does not add up is also demonstrated by the attempt to apply the concept to attacks below the military threshold. For example, in recent years, NATO has come to qualify so-called “hybrid” attacks such as cyberattacks, disinformation campaigns, or acts of sabotage as threats that could trigger the Washington Treaty’s famous Article 5 clause of collective self-defense. In practice, however, the unabated hybrid activities against NATO states show that such threats leave hybrid actors unimpressed. They calculate—correctly—that NATO, which only has military instruments at its disposal, will not respond to non-military attacks by taking up arms. Hence, attempts by some analysts to extend the principle of deterrence to the grey zone of hybrid conflicts through creative wordsmithing (“deterrence by entanglement”) remain unconvincing.
One problem with this kind of discussion is that the concept of deterrence is being damaged if it is applied to situations in which it is almost bound to fail. Another problem is the claim that Russia has long been waging a “hybrid war” against the West, which is often heard in the context of the war in Ukraine, is not only highly problematic in terms of international law, but also leads some observers to call for tougher Western “countermeasures,” including the use of military means.
However, anyone who wants to respond militarily to non-military pinpricks is moving beyond deterrence in favor of an extremely risky “tit-for-tat” strategy, as the opponent would then also be tempted to respond militarily. Hence, the response to such threats does not lie in banking on military deterrence, but in strengthening the resilience of the state, its economy, and its society.
A Better Understanding of Deterrence
The current Western debate, in which deterrence is simultaneously over- and underestimated, shows that the alleged rediscovery of this concept has remained woefully incomplete. While the shock caused by Russia’s attack on Ukraine has made many observers recognize the growing importance of deterrence, they only use this concept selectively, in order to support their own positions.
To be sure, since deterrence is not an exact science, it does not offer precise policy advice. However, as the West is seeking to prepare for a world of strategic competition, including by increasing national defense budgets, it is high time to understand which threats can be deterred by what kind of means—and which cannot. Calls to increase the “nuclear IQ” are therefore necessary, but not sufficient. Without a more mature understanding of the opportunities and limits of deterrence—nuclear as well as conventional—the West runs the risk of building its security on delusions.
Michael Rühle is a former NATO official. Before his retirement in 2023, he was head of the Climate and Energy Security Section, Emerging Security Challenges Division, at NATO Headquarters in Brussels. In a career spanning 32 years, he also worked in policy planning and speechwriting.
