David J. Lonsdale, Extended Deterrence:  Back to the Future, No. 541, December 1, 2022
Extended Deterrence:  Back to the Future

David J. Lonsdale
David J. Lonsdale is a Senior Lecturer in War Studies, at the University of Hull, UK. His publications include Understanding Contemporary Strategy, Understanding Modern Warfare, and Alexander the Great: Lessons in Strategy.

Introduction

It is well understood that deterrence is a challenging strategic activity.[1] Said challenge is exacerbated when we shift attention to extended deterrence. This is largely because the success or failure of deterrence rests on a complex and indeterminate relationship between the deterrer and the target actor(s). Critical to the outcome of that relationship is a process that comprises the assets, actions and attitudes of the deterrer and subsequent response of the target. Credibility lies at the heart of that process. Traditionally, credibility is understood to be dependent upon the so-called three Cs of credible deterrence: capability, commitment and communication. However, it is here proposed that a fourth C is equally essential to the outcome of a deterrence relationship: context. It is from this fourth C that the real difficulties of extended deterrence emerge. In extended deterrence, context becomes more variable and incorporates a wider gamut of national security interests. In order to better understand the challenges of extended deterrence, this paper first discusses the complex interactions that exist amongst the four Cs of credible deterrence. From here, the work identifies “Flexible Response,” a deterrence concept first developed during the Cold War, as a posture that can help strengthen the credibility of extended deterrence.

The Four Cs of Credible Deterrence

Since the act of deterrence is founded upon a threat, the credibility of said threat is an essential enabler of a successful deterrence strategy. In turn, credibility is the product of a complex interplay amongst the aforementioned four Cs of deterrence. It is within this complex interplay that the context element of extended deterrence comes to the fore.  Generally speaking, capability demands that the deterrer has forces that are sufficient and proficient enough to enact the threat made. Estimations of proficiency and sufficiency are dependent upon the context, which, in turn, encompasses the policy objectives at stake, the military objectives thereof, and the nature of the enemy. Forces that produce a threat that is too large or too small for the situation at hand will necessarily undermine the credibility of deterrence. Furthermore, operationally ineffective forces similarly are likely to weaken credibility. In a purely bipolar relationship, sufficiency and proficiency, although still challenging to acquire, are easier to gauge. In a multipolar system, with various extended deterrence commitments, the capability challenge is severely enhanced. In light of these thoughts, in its nuclear force structure the US must ensure it has sufficient flexibility to deal with a range of capability requirements. Moreover, those forces must be capable of effective operations against a variety of potential adversaries in different regional settings.

When it comes to commitment, context is equally problematic. Threatening to unleash nuclear war poses a credibility challenge in any context. That being said, nuclear release in defence of the homeland enjoys a degree of plausibility. The level of plausibility would seem to diminish with the use of nuclear weapons in support of allies (the very essence of extended deterrence). Moreover, not all allies are equal when it comes to national security interests. A deterrer will have to work harder in some contexts to successfully display their commitment to use nuclear weapons. Once again, we are left to conclude that flexibility and proficiency in capability are essential ingredients of commitment for extended deterrence. In this way, the theorist Carl von Clausewitz is compelling when he writes that the use of force (or threat thereof) is proportionate to the measure of the policy objectives in play. [2] Allies lower down the national security agenda may still require cover from the US nuclear umbrella. However, it is unlikely that more marginal interests would justify large-scale nuclear conflict that threatens enormous casualties, both in the region and possibly the US homeland. In these instances, the deterring power needs far more limited and controlled nuclear options that can be successfully employed against enemy forces. With such capabilities in place, it is easier to demonstrate genuine commitment.

Finally, communication is also subject to the vagaries of context. Each security challenge is unique, conditional on the particular politics, strategic cultures, and balance of forces in play. [3] Consequently, signaling intent with nuclear weapons is challenging. As Thomas Schelling reminds us, deterrence communication is dependent upon establishing a common understanding. [4] If deterrence is to succeed, the target actor must be able to clearly decipher the implications of the words and actions of the deterrer. Again, flexibility in capabilities and posture would seem a necessary response to this contextual communication challenge. A broader, more flexible set of capabilities gives one a stronger hand when communicating a credible threat in different scenarios. With a flexible force structure, one can shape the threat to the issue at hand. Indeed, the possession of appropriate capabilities is a form of communication itself. As former U.S. Under Secretary of Defense for Policy, Walter Slocombe notes, ‘forces themselves play the dominant role in perceptions and, therefore, in deterrence.’ [5] Warheads and delivery systems speak louder than words. Nonetheless, the latter also matter. Robust and positive comments about one’s nuclear forces further strengthens and clarifies deterrence communication in a complex extended deterrence world. The opposite is also true. Repeatedly expressing horror and negativity about nuclear weapons may leave one looking like a reluctant nuclear power and thus a doubtful deterrer.

Lessons from the Cold War

Although the security challenges we now face are by definition unique, much that we see in the contemporary world is neither entirely new nor requires wholly novel approaches. As we grapple with the challenges of extended deterrence in the third decade of the 21st Century, it will prove profitable to return to some ideas and concepts developed during the Cold War. And yet, there has been a deliberate attempt in some influential quarters to consign Cold War ideas to the dustbin of history. Perhaps most notably, President Obama publicly stated that he wanted “to put an end to Cold War thinking”. [6] This attitude is problematic because the core challenges of extended deterrence were worked through during the first nuclear age. The hard intellectual graft was done as the world first tried to make strategic sense of nuclear weapons. As the theorist Colin Gray notes, strategic sense is a valuable, hard-won resource. The two primary sources of which are robust theory and historical reflection. [7] The Cold War provides a rich source of empirical evidence on extended nuclear deterrence, and proved to be a fertile ground for theoretical development on the subject.

Indeed, it was partly in response to the challenges of extended deterrence that US nuclear strategy developed from the relative simplicity of Massive Retaliation (first enunciated in 1954). [8] If we track the trajectory of US nuclear strategy during the Cold War, we see an ever-growing quest for flexibility, credibility, and strategic utility. From the early days of Massive Retaliation, US nuclear strategy developed along the lines of limited nuclear options (LNOs), Flexible Response, countervailing, and escalation control. Highlighting the centrality of credibility to this process, much of the key foundational theory of the 1960s was a response to the perceived credibility gap in Massive Retaliation, especially in relation to more marginal threats to security. Furthermore, Albert Wholstetter’s influential, The Delicate Balance of Terror, acted as an operational wake-up call to all those who assumed that US retaliatory forces at the time would suffice. [9] Taken as a whole, the experience of US nuclear strategy during the Cold War, with its strong extended deterrence character, reveals that, when it comes to nuclear strategy, the details can genuinely matter. Furthermore, from that experience we can conclude that a secure and robust deterrence posture must be built upon an equally robust operational capability. Relying upon some vague, general threat and capability (a la Massive Retaliation) will not cut the mustard. That was true then, and is even more so now.

Declining Credibility

Unfortunately, much of the good work in nuclear strategy has been lost in recent years. This was especially evident during the Obama administrations. In an effort to reignite the disarmament agenda, the 2010 Nuclear Posture Review (NPR) sought to reduce the role of nuclear weapons in US national security policy. As one senior state department official at the time noted, the NPR’s “first step” involved “develop[ment of] a nuclear force structure and posture for use in the negotiations” of the successor agreement to START I. [10] And, although the Obama administrations did not ultimately adopt the sole use criterion, they came close. Aside from a rather unconvincing threat against NPT non-compliant actors, the 2010 NPR explicitly states that U.S. nuclear weapons have only one role: “deterrence of nuclear attack on the United States or our Allies and partners.”[11] This left the US with a far less flexible declared deterrence policy. Moreover, with such a negative attitude to nuclear weapons, driven by the nuclear zero agenda, the US was left looking like a reluctant and declining nuclear power. Taken together, these developments arguably undermined the credibility of US nuclear deterrence, especially when faced with complex extended deterrence security challenges.

Thankfully, some of the damage done under Obama was rectified during the Trump administration. In this respect, the 2018 NPR was a significant step in the right direction. Perhaps with an eye to the communication element of credible deterrence, the 2018 NPR signalled an increased emphasis on nuclear weapons in national security, ‘there is no higher priority for national defense’.[12] Allied to an enhanced modernisation programme, an emphasis on flexibility, and discussion of post-deterrence operations, the tenor of the Trump Administration was far more robust in terms of nuclear strategy. There was, however, one glaring problem with the 2018 NPR: the explicit insistence that the review ‘is not intended to enable, nor does it enable, nuclear war-fighting’. [13] From the perspective of strategic sense, the obvious response to such a statement is ‘why not?’. As will be argued below, prudent operational nuclear planning is in tune with the nature of strategy, enhances the credibility of deterrence, provides essential options should deterrence fail, and fulfils a moral obligation under the Just War rubric.

As might be expected, especially in light of recent geostrategic events, the newly released 2022 NPR takes a middle ground between the 2010 and 2018 variants. Whilst still advancing the aim of reducing the role of nuclear weapons in US strategy and seeking to bolster arms control efforts, the new review acknowledges the increased threat environment and its implications for extended deterrence. In particular, it is noteworthy that the 2022 review emphasises the importance of flexibility and even discusses ‘achieving objectives’ as a role for nuclear weapons in the event of deterrence failure. The review offers no real details on what operational objectives could be sought in nuclear conflict. It does, however, include the reasonably robust statement that ‘the United States would seek to end any conflict at the lowest level of damage possible on the best achievable terms.’[14] Still, despite containing this rather 2018-esque statement about nuclear use, the 2022 NPR also spends quite a bit of time discussing arms control, crisis stability, managing escalation risk, and the desire to work towards a sole purpose declaration. One is left with the impression that the Biden Administration is a nuclear sceptic reluctantly coming to terms with the harsh realities of the contemporary geostrategic world.

The Need for Prudent Operational Planning[15]

As already noted, there are four main drivers for serious operational nuclear planning. First, it chimes with the nature of war and strategy. As clearly indicated by Clausewitz, ‘it is inherent in the very concept of war that everything that occurs must originally derive from combat’.[16] Clausewitz recognised that even when battle does not occur (including, we might say, in a deterrence relationship), the outcome is premised on calculations of what would happen should battle have been fought.[17] In this sense, it is a conceptual anathema to decouple deterrence from credible operational capabilities. As a retort to this line of thinking, it may be argued that Clausewitz’s theory, written in the 19th Century, does not relate to nuclear weapons. However, it is worth noting that Bernard Brodie, the father of the nuclear age, described Clausewitz’s book as timeless.[18] More to the point, one should note that the natures of strategy and war are universal, encompassing all forms of military power, including nuclear weapons. In this way, the deterrence potency of nuclear weapons is premised on their prospective military use, or rather their credible threat to deliver firepower and thereby achieve politico-military objectives. To reference an appropriate analogy; consider a modern aircraft carrier. Regarded by many as the capital ship of contemporary naval forces, the carrier’s operational and strategic potency stems primarily from its ability to launch various forms of destructive airpower. In both cases, nuclear weapons and the aircraft carrier, strategic effect does not emanate from the mere existence of the weapon or platform. Rather, it originates in their operational capabilities.

Second, flexible operational capabilities likely enhance credibility. It has already been noted that establishing robust credibility is fraught with challenges. If all you have on the table is annihilation or surrender, an adversary may reasonably assume that you will not choose the former on an issue that is less than vital to your national security interests (often evident in extended deterrence). In more ambivalent security scenarios, one requires the ability to wage controlled, limited, survivable forms of nuclear war. In this way, a flexible nuclear posture gives deterrence more substance, the underpinning threat becomes more tangible. To somewhat labour the point, with more concrete and diverse options in play, one’s resort to nuclear weapons looks more plausible, and therefore more credible for deterrence purposes.

This does not mean, however, that larger nuclear options are off the table. Indeed, there exists an interesting deterrence relationship between limited and unlimited nuclear options. Limited nuclear options likely make the threat more plausible. However, in certain scenarios a limited threat may not be enough. An enemy may be willing to risk much over an issue of considerable import. It is important, therefore, to integrate limited and unlimited options on the ladder of escalation.[19] In this way, limited options make the threat more tangible, but it is the fear of escalation to nuclear annihilation that underwrites the whole deterrence dynamic. The process of escalation can be exploited in two ways. Thomas Schelling proposed the threat that leaves something to chance, whereby the credibility of escalation follows from the possibility of unforeseen or unintended consequences of earlier actions. Although seemingly irrational, the rationale for this approach is the inherent extreme caution an enemy will have with regard to nuclear war in general. The second, and preferable, means of providing credibility to threats is via escalation control. Under this second approach the deterrer requires sufficient nuclear forces at each level of escalation to convince the enemy to decide to backdown.

Third, to put it bluntly, deterrence may fail. As much as we may desire to live in a world in which deterrence holds and aggression does not occur, it is strategically irresponsible to ignore the possibility of deterrence failure. Consequently, the US must be prepared for nuclear war to the extent feasible.  As noted, to its credit the 2018 NPR ventured into post-deterrence possibilities. Whilst a welcome development, this was a limited foray that seemed not to go beyond the confines of countervailing, damage limitation and intrawar deterrence. [20] Beyond these admirable goals, the US must have the capability to manage escalation and seek to achieve policy objectives in nuclear conflict, including the mitigation of damage to Western society and recovery. There are those who postulate that nuclear weapons, in use, are astrategic; that they cannot serve any rational policy objective. [21] However, in response we once again turn to strategic sense. Without the conscious pursuit of policy objectives in war, strategy ceases to function as a rational instrument of politics. This universal principle of strategy is applicable to, and necessary in, nuclear war because deterrence is not fool proof.

To be clear, the US must have a theory of engagement with enemy forces to attain military objectives in the pursuit of policy goals. Precisely what that attainment would look like is entirely dependent on the specific scenario faced, most especially the nature of the enemy and the policy objectives sought. It may be; indeed it is highly likely, that in a nuclear conflict survival and recovery of the nation-state (in some form) would be a primary policy objective. That objective, in itself, requires mature operational capabilities and planning to prosecute a damage limitation campaign. However, the complex contemporary security environment could deliver a range of policy objectives that need pursuing. And, whilst it is undoubtedly true that nuclear weapons will only ever be used in extremis by rational actors, they are still weapons that may be needed in a range of potential scenarios, and all actors may not fit the rational profile expected. On a more general point, we must think about possible end states in nuclear war. Bernard Brodie is once again compelling when he wrote, ‘So long as there is a finite chance of war, we have to be interested in outcomes; and although all outcomes would be bad, some would be very much worse than others.’[22]

Finally, it can be argued that prudent planning for flexible response options and limiting damage is a moral requirement under the Just War tradition. To clarify, the Just War tradition is a well-established means to ensure that the resort to, and conduct of, war is morally justified. Whilst it is true that nuclear weapons pose a challenge to established notions regarding the ethics of war, they do not exist in a moral vacuum. Amongst other criteria in the Just War tradition, for a war to be considered just there must be a reasonable prospect for success. The logic behind this principle is that, without the prospect for success the costs of war would be borne for no gain or goal. It is axiomatic that success requires a theory for attaining desired goals, even if those goals are limited to survival and the potential for recovery. In the absence of the latter, it is unlikely that a prudent, robust operational capability would be developed. Accordingly, if deterrence fails, nuclear weapons would likely be used in an ad hoc fashion, guided by nothing more than some vague hope that strategic effect would accrue. Moreover, for the jus in bello criteria of proportionality and discrimination to be fulfilled, nuclear war must be fought in a controlled and discriminant fashion. Again, this requires diverse, flexible response options.

Concluding Thoughts

It is not the claim of this paper that the lessons of the Cold War can be simply mapped onto the current security environment without adaptation. Every security challenge is unique and must be approached with an eye to the particular. Nor is it claimed that the unique characteristics of nuclear weapons can be ignored. Their enormous destructive potential must be respected and clearly taken into account. Nonetheless, the nature of strategy is universal, and must be given due respect when constructing nuclear weapons policy. As we grapple with the security challenges of the 21st Century, we should acknowledge that much of the code of extended deterrence was decrypted in the first nuclear age. In particular, we should respect the lineage of flexibility, credibility and strategic utility. Most evidently, this requires serious operational planning and flexible response options. To cite Herman Kahn, who taught us to think about the unthinkable, when faced with the strategic challenge of nuclear weapons there has to be an alternative beyond annihilation and surrender.[23] A mature and confident operational capability oriented around flexible response options provides such an alternative. God willing, it would provide the credibility required to ensure a robust deterrence posture; and in the face of deterrence failure would help support the continuation of strategy and the prospect for protecting our way of life.

[1] Keith B. Payne, “Deterrence is not Rocket Science: It is More Difficult,” Journal of Policy & Strategy, 2/3, 2022, pp. 25-36.

[2] This is discussed at some length in Book 1, Chapter 1 of Carl von Clausewitz, On War (Princeton, NJ: Princeton University Press, 1978).

[3] Indeed, it was nuclear strategy that inspired the development of the strategic culture literature. For details on culture in strategy see Colin S. Gray, Perspectives on Strategy (Oxford: Oxford University Press, 2013), pp. 79-115.

[4] Thomas C. Schelling, The Strategy of Conflict (Cambridge, MA: Harvard University Press, 1980).

[5] Walter Slocombe, “The Countervailing Strategy,” International Security, 5, 4 (Spring 1981), pp. 18-27.

[6] Cited in Hans M. Kristensen, “Obama and the Nuclear War Plan,” available at http://www.fas.org/programs/ssp/nukes/publications1/WarPlanIssueBrief2010.pdf.

[7] Colin S. Gray, Theory of Strategy (Oxford: Oxford University Press, 2018), pp. 140-147.

[8] For details on Massive Retaliation see Lawrence Freedman & Jeffrey Michaels, The Evolution of Nuclear Strategy, 4th Edition (London: Palgrave Macmillan, 2019), pp. 119-120.

[9] Albert J. Wohlstetter, “The Delicate Balance of Terror,” Foreign Affairs, 37 (1959), pp. 211-34.

[10] Quoted in Anna Loukianova, “The Nuclear Posture Review Debate,” available at http://www.nti.org/eresearch/e3 nuclear posture review debate.html.

[11] U.S. Department of Defense, 2010 Nuclear Posture Review (Washington, DC: Department of Defense, 2010), p. 17, available at https://dod.defense.gov/Portals/1/features/defenseReviews/NPR/2010_Nuclear_Posture_Review_Report.pdf.

[12] U.S. Department of Defense, 2018 Nuclear Posture Review (Washington, DC: Department of Defense, 2018), p, 48, available at https://media.defense.gov/2018/Feb/02/2001872886/-1/- 1/1/2018-NUCLEAR-POSTURE-REVIEW-FINAL-REPORT.PDF.

[13] Ibid, p. 12.

[14] U.S. Department of Defense, 2022 Nuclear Posture Review (Washington, DC: Department of Defense, 2022), p. 8, available at https://s3.amazonaws.com/uploads.fas.org/2022/10/27120404/NPR2022.jpg.

[15] This section of the paper is built upon intellectual foundations which were most fully developed by Colin S. Gray and Keith B. Payne. See Colin S. Gray & Keith B. Payne, “Victory is Possible,” Foreign Policy, 39, (1980), pp. 14-27 and Colin S. Gray, “War-fighting for Deterrence,” Journal of Strategic Studies, 7:1, (1984), pp. 5-28.

[16] Clausewitz, p. 87.

[17] Ibid., p. 97.

[18] Bernard Brodie, “The Continuing Relevance of Clausewitz,” in Carl von Clausewitz, On War (Princeton, NJ: Princeton University Press, 1978), p. 46.

[19] The Ladder of Escalation is most famously explored in Herman Kahn, On Escalation: Metaphors and Scenarios (London: Pall Mall Press, 1965).

[20] 2018 Nuclear Posture Review, op. cit., pp. 23 & 30.

[21] For a reflective discussion of this subject see Freedman and Michaels, pp. 665-678. Rather surprisingly, one such author is Colin S. Gray, who in his last great work of theory concluded that “there can be no meaningful nuclear strategy. If used in warfare, nuclear weapons would be most likely too powerful to serve political purposes.”  However, by this, Gray did not mean that deterrence itself should be separated from prudent operation planning. Colin S. Gray, Theory of Strategy (Oxford: Oxford University Press, 2018), p. 123.

[22] Bernard Brodie, Strategy in the Missile Age (Princeton: Princeton University Press, 1959), p. 278.

[23] Herman Kahn’s core writings on nuclear strategy include the aforementioned On Escalation, Thinking About the Unthinkable (New York: Horizon Press, 1962), On Thermonuclear War (Princeton, N.J: Princeton University Press, 1960), and Thinking about the Unthinkable in the 1980s (New York: Simon & Schuster, 1984).

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