Deterrence: precarious in theory, effective in practice

During the 1962 Cuban Missile Crisis, the famed US film director Stanley Kubrick decided to move to Australia. He reckoned that in a nuclear war between the United States and the Soviet Union, the fallout would be less Down Under. However, when he learned that he would have to share the bathroom of the ship’s cabin with the passengers of the adjacent cabin, he cancelled the trip. His fear of sharing a bathroom with strangers was greater than his fear of nuclear war. Kubrick stayed home and dealt with his nuclear fears by making Dr. Strangelove, the ultimate cinematic masterpiece about the dilemmas of nuclear deterrence.

Kubrick’s behavior may strike one as paradoxical, yet nuclear weapons are themselves paradoxical. Their destructive power makes their use potentially suicidal, but it is precisely the fear of the potentially catastrophic consequences that moderates international relations. Indeed, while the nuclear age has seen many conventional wars, no war between nuclear powers has ever occurred. Nuclear deterrence did not prevent each and every conflict, but it clearly played a role when existential issues were at stake. Former US Secretary of Defense James Schlesinger put it best when he said that nuclear weapons were being “used” every day.

It is therefore hardly surprising that nuclear deterrence is now re-entering the Western security debate. Given Russia’s high-testosterone nuclear rhetoric, North Korea’s nuclear grandstanding, and with nuclear rivalries looming in Asia as well as the Middle East, a reaffirmation of nuclear deterrence as an important element of Western security strategy was inevitable.

However, re-discovering nuclear deterrence is easier said than done. Since the end of the Cold War, the Western strategic community had lost interest in that concept. With the security agenda dominated by the fight against terrorism and military interventions in failing states, nuclear deterrence appeared like a relic of a distant past. Hence, to make nuclear deterrence again a useful tool in the West’s approach to security, it is important to relearn its major characteristics – and, above all, its limitations:

Credibility. A large nuclear arsenal does not automatically translate into a credible deterrent. Since a state will only take nuclear risks in defense of existential interests, an aggressor may not be deterred if he concludes that the issue at stake is not existential to the defender. Hence, allies of nuclear powers constantly need to be reassured by their protector. According to former British Defence Secretary Denis Healy, it took only 5-percent credibility to deter the Soviet Union, but 95-percent to assure one’s allies.

Threats. Deterrence revolves around threats – and no one likes being threatened. Hence, what might look to oneself like a perfectly defensive deterrence posture may look to others like intimidation. To avoid such an outcome, one must remain aware that an adversary might interpret one’s political declarations, military exercises or procurement decisions in ways far more sinister than what is intended or what one might consider reasonable.

Rationality. A stable deterrence regime requires all actors to adhere to a “rational” costbenefit calculus. Thus, nuclear deterrence cannot work against “irrational” actors, e.g. suicidal fanatics. However, deterrence could also fail when rationality evaporates in a crisis, when leaders are under extreme pressure and regime survival becomes the key issue. As humans fear loss more than they value gain, one should avoid pushing a nuclear adversary into a corner.

Reassurance. A deterrence message has at least two addressees: one’s opponent and one’s own population. The true art of deterrence is to impress the former without frightening the latter. That is why governments must carefully weigh their rhetoric and why, in some instances, not deploying potentially controversial military hardware can be the wiser choice.

Communication. Deterrence is not a substitute for dialogue with the adversary. Without communication between the antagonists, deterrence will not be the solution, but could well become the problem. To avoid miscalculations, a stable deterrence regime requires a degree of transparency and predictability. In other words: deterrence requires rules or at least agreed understandings, however tacit.

How does NATO fare in the nuclear deterrence business? Pretty well, considering that the nuclear dossier had been largely ignored for two decades. While Moscow – in what may be a distinctly “Russian” idea of deterrence – is constantly boasting about its nuclear strength, NATO allies have stayed clear of such grandstanding. Nor is NATO mimicking Russia’s doctrine of using nuclear weapons to “de-escalate” a conflict. The Alliance simply states that nuclear weapons are “unique,” that any employment of nuclear weapons against NATO “would fundamentally alter the nature of a conflict,” and that the circumstances in which NATO might have to use nuclear weapons are “extremely remote.”

Such careful statements indicate that the Allies’ focus is not on beefing up NATO’s nuclear arsenal, but r a t h e r on preventing Russia from miscalculating about its own.

NATO’s reaffirmation of nuclear deterrence does not suggest that Allies would have to renege on their commitment to create the conditions for a nuclear-free world. For the foreseeable future, however, these conditions simply do not exist. The same holds true for initiatives to ban nuclear weapons: In the current security environment, advocating initiatives that delegitimize Western defense policies while not seriously affecting “managed democracies” (Vladimir Putin) appears counterproductive.

Does this sound the “all-clear”? Hardly. With more countries obtaining nuclear weapons, deterrence will become even more difficult and prone to failure than the Cold War nuclear standoff. Nuclear deterrence must not be regarded as an eternal condition, but as a “time-buying strategy”; it should provide the time needed to overcome the political antagonisms that make nuclear deterrence necessary in the first place. Until then, one must take solace in Lawrence Freedman’s apt observation that deterrence may not work that well in theory, yet tends to work in practice.

A version of this article appeared in print in February, 2017, with the headline “The bomb is back”.

Michael Rühle is head of the Energy Security Section in NATO’s Emerging Security Challenges Division.