Deterrence[1] for the sake of security is something in which policy makers have historically placed significant faith, expecting it to dissuade aggression.[2] There are two broad categories of deterrence: Deterrence by punishment, which is “the threat of harming something the adversary values if it takes an undesired action”,[3] and deterrence by denial, “’hardening’ targets in the hope of making an attack on them too costly to be tried”.[4] Both of these categories essentially consist of altering the cost-benefit analysis of enemy action.[5] The introduction of nuclear weapons, with their enormous punitive power, allows deterrence to “be accomplished by weapons which might have no rational use for defence should deterrence fail”,[6] and has been widely credited with the lack of major conflict over the past six decades.[7]

This view is challenged by Andrew Brown and Lorna Arnold in “The Quirks of Nuclear Deterrence”. Brown and Arnold argue that, like contraception, one cannot tell if deterrence has been successful, only if it has failed. Although nuclear deterrence “may perhaps have worked” between the US and USSR, “there is precious little historical evidence that it prevented ‘sub-nuclear’ wars”.[8] In supporting their call to reassess the “effectiveness, extravagance and risks of nuclear deterrence”,[9] Brown and Arnold examine the problems of credibility, human nature, and terrorism. Although they call upon other factors as well, these three will be the focus of this paper, as they are major aspects of Brown and Arnold’s analysis and they stand to be improved or elaborated upon.

For deterrence to fail, it must first be established. This requires that a state’s resolve to act upon its threats is communicated in a credible manner to its opponents.[10] Although this may seem simple at first glance, the disproportional nature of nuclear retaliation complicates matters. Keith Krause addresses this issue in his paper “Rationality and Deterrence”, observing that credibility is “perhaps the central puzzle of deterrence theory”.[11] Krause observes that in a nuclear deterrence model, credibility rests on a specific rationality of irrationality. That is to say, once one is attacked, he loses his reason to retaliate. Therefore one has reason to appear unreasonable. As Brown and Arnold point out, this is demonstrated by the Berlin crisis of 1948, where the assumption of the rationality of American leadership convinced Stalin that there would be no escalation to nuclear war.[12]

While Brown and Arnold focus on the difficulties of rational irrationality and retaliation against nuclear attack, Krause highlights the important question of matching credible threats to individual boundaries in conventional conflict, referring to “salami tactics”.[13] In this respect, Krause has placed his focus more appropriately. While presumptions of rational action play into whether a state will follow through on threats, those scenarios are predicated on action contravening the boundaries placed by the deterring state. Such actions are not likely to began dramatically, but are more likely to begin with testing of boundaries, allowing and requiring action to demonstrate resolve. Therefore, a discussion of rational irrationality is superfluous unless accompanied by an examination of salami tactics. Brown and Arnold do, however, direct attention to the notion of minimum deterrence, or MD,[14] which presents one of the strongest answers to the credibility dilemma available. The vague threat of severely limited nuclear retaliation is a more credible threat to make (in that it requires less resolve), and it leaves the enemy state with ample cities left to lose (so that further threats can be levelled against counter-retaliation), while still threatening unacceptable losses by any account.

However, establishing deterrence does not ensure its success. It is possible in theory, and demonstrated in practice, that the peace may be breached despite the threat being believed. While Brown and Arnold state that the Berlin Crisis represents a failure to establish deterrence, they hold that the Korean War represents an outright failure of deterrence.[15] Mao Zedong, they explain, “seemed to believe that China’s enormous population meant that it would always triumph after a nuclear war”.[16] As the authors point out, totalitarian dictators represent an exceptional case,[17] but their resistance to deterrence still requires explanation. Explaining this exception requires a more developed theory of the nature of humanity as a whole than can be found in “Quirks of Nuclear Deterrence”.

In “Thucydides and Deterrence”, Richard Lebow examines the Thucydidean account of the Peloponnesian War as a data set for understanding why deterrence fails. His approach differs wildly from that of Brown and Arnold, but offers a greater focus on the motivations of actors and the philosophy behind those motivations. Lebow, using a classical conception of the soul as tripartite, delineates the effect of deterrence on men of differing compositions. He uses the example of the Berlin Crisis to demonstrate the ineffectiveness of deterrence when actors are motivated by fear.[18] Fear, he explains, is the result of the loss of control of reason over either appetite or spirit.[19] He also observes that deterrence fails against actors who are primarily motivated by spirit.[20] These limitations of deterrence, combined with the necessity of irrationality entailed in establishing credibility, bring about a very restrictive dynamic of deterrence. If we accept Lebow’s interpretation, then deterrence can only exist as a function of interaction between two entities that are motivated by appetites rather than spirit, and have capable, but limited, reason. In Platonic terms, this restricts deterrence specifically to oligarchies and democracies. Furthermore, while tyrannies are also motivated by appetites, they would lack the necessary oversight of reason for deterrence to alter their behaviour. This dynamic agrees with the failure of Athenian deterrence against more timocratic polities, the failure of deterrence against totalitarian dictators, and its seeming success against somewhat rational democracies. This dynamic is also in line with (and expounds upon) the pre-existing logic of deterrence. Deterrence will be not be established in cases of excessive rationality, and will fail when attempted against entities that are not in accord with the aforementioned dynamic.

Understanding now that certain individuals will be unable to be deterred due to human nature, we must determine whether this applies to the growing threat of terrorism. In order to ascertain whether Brown and Arnold are right in saying that “terrorists lack the rationality, command structure and values necessary to be deterred”,[21] we turn to the ambitiously named “Deterring Terrorism: It Can Be Done” by Robert Trager and Dessislava Zagorcheva. They argue that terrorists are not irrational in “a sense that makes them impossible to deter”,[22] rather their values are atypical. In this respect, most terrorists are akin to timocratic entities, and are indeed immune to deterrent threats aimed at their liberty or livelihood. However, the particular emphasis they place on their political goals make these goals viable alternatives as targets of deterrence.[23] Furthermore, more traditionally motivated actors often perform necessary functions in terrorist operations and are vulnerable to deterrence of a more traditional variety.[24]

That said, Brown and Arnold are quite justified in stating that nuclear deterrence has no use against terrorists.[25] The “return address” problem is similarly identified by Trager and Zagorcheva,[26] but the diffuse nature of terrorists only presents an impasse for nuclear deterrence, while it increases (exponentially) the cost of effective conventional deterrence. Therefore, it is open to question whether, if a terrorist group acquired a nuclear weapon, they could indeed be deterred from using it. Meagre accommodation of political goals, the threat of absolute termination of those goals in the case of an attack, and a commitment to exorbitant conventional retaliation could serve to alter the cost-benefit analysis of the terrorists to such an extent that not using the weapon would be more productive for their cause. However, these methods will not work on a sufficiently motivated group whose objective preferences are diametrically opposed to the deterrer’s, a reality that renders denying nuclear capability to such groups of enormous importance.

Given these realities, it seems as though Brown and Arnold are justified in seeking to reassess the place of nuclear deterrence in the world. However, they give deterrence too little credit. Given an accurate evaluation of one’s opponents, and an understanding of how different people will react to a deterrent threat, deterrence can be a valuable tool in a policy maker’s arsenal. In practice, it is often “the overvaluation of reason”[27] which leads to failures of deterrence. Understanding that actors may be motivated outside of their own personal interests and understanding how to threaten “something the adversary values”,[28] regardless of what it may be, will allow for more effective deterrence against ‘spirited’ opponents. Unfortunately, all of these evaluations will still need to be made in a dynamic which includes dissimulation, self-effacement, incomplete information, and heated emotions. This means that the difficulty of successfully applying deterrence is enormous. Especially with regards to nuclear deterrence, where failure threatens human survival, it is clear that finding alternative means of ensuring security should be a priority.

Bibliography

Andrew Brown & Laura Arnold, ‘The Quirks of Nuclear Deterrence’, International Relations, vol.24, no.3, (2010)

Keith Krause, ‘Rationality and Deterrence in Theory and Practice’, Contemporary Strategy and Security, Snyder (ed.), (New York: Routledge, 1997)

Richard Ned Lebow, ‘Thucydides and Deterrence’, Security Studies, vol.16, no.2, (2007)

Glenn Snyder, Deterrence and Defence, (Princeton University Press, 1961)

Robert Trager & Dessislava Zagorcheva, ‘Deterring Terrorism: It Can be Done’, International Security, vol.30, no.3, (2006)