Within the next five years, the world will face for the first time since the early 1970s a world without meaningful formal arms control agreements, nuclear or conventional, between Russia and the United States. This is a profoundly important development for the role that nuclear weapons play in international security. Rather than be drawn back to Cold War principles that increase the risk of nuclear warfighting, however, nuclear-armed states should reconsider the demandingly different deterrence environment of the twenty-first century and shift their nuclear doctrines, postures, and capabilities unambiguously toward strategic deterrence.

John Gower
John Gower is a retired rear admiral from the Royal Navy with thirty-six years’ service.

In brief: the New Strategic Arms Reduction Treaty (START)—known as START III in Moscow—is running on vapors to its current end date in 2020. The United States is unlikely to agree to a short extension (for up to five years) of New START, given that the only exchange Presidents Vladimir Putin and Donald Trump have had on the issue made the latter’s opposition clear (though he changes his mind frequently). Beyond New START, the chances of a new arms control agreement being negotiated are slimmer than at any time since the first Strategic Arms Limitation Talks (SALT I) in the late 1960s. The Anti-Ballistic Missile (ABM) Treaty was dissolved in 2002 when the United States withdrew from the agreement, while the Intermediate-Range Nuclear Forces (INF) Treaty is, at best, in limbo with both Russia and the United States alleging material violations by the other. The United States has not ratified the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Despite being one of the major components of détente and stability in Europe for the last thirty years, conventional arms control in the European theater is also struggling to remain relevant.

This is a stunning reversal of the optimism prevalent just a few years ago. During Barack Obama’s presidency, prospects for reducing nuclear dangers and making genuine progress toward the aim of the Nuclear Non-Proliferation Treaty (NPT), through reductions in the salience and stockpiles of nuclear weapons, was heightened following developments such as Obama’s 2009 Prague speech and the subsequent 2010 U.S. Nuclear Posture Review. In turn, these developments strongly influenced the UK’s Strategic Defense and Security Review in 2010 and NATO’s Strategic Concept of the same year. I worked with the United States and NATO allies in formulating UK national and alliance nuclear policy throughout this period, and there was a genuine belief that progress was possible. That optimism, and a wider hope of reducing the salience of nuclear weapons in international security policy, has since diminished. The trajectory of nuclear capabilities in several nuclear-weapon-capable states (NWCS) is unmistakably upward.1

Into this nadir of international trust has stepped a seriously unpredictable U.S. administration that has posited a more expansive vision of nuclear deterrence and requested several new types of nuclear weapons to carry it out. A new and rhetorically hostile nuclear power—North Korea—has emerged on the U.S. Pacific flank. Nuclear alliances, NWCSs, and nations for whom nuclear weapons states offer extended deterrence guarantees are facing critical choices over the next two decades about how best to maintain strategic stability, including nuclear deterrence. Despite the frustrations of the non-nuclear-weapon states at these developments, given vent in the adoption by 122 countries in July 2017 of a materially ineffective and unrealistic UN Treaty on the Prohibition of Nuclear Weapons,2 there is a genuine risk that the major and some minor nuclear powers are slipping back into an acceptance of limited nuclear warfighting as a palatable option.

Both the U.S. administration’s National Defense Strategy and Nuclear Posture Review (NPR) significantly strengthen the salience and recentralize the role of a broader range of nuclear capabilities in U.S. defense and foreign policies. The unclassified summary of the U.S. National Defense Strategy, for instance, signals a return to wider applicability of nuclear capabilities, including the deterrence of strategic non-nuclear attack:

The Department will modernize the nuclear triad—including nuclear command, control, and communications, and supporting infrastructure. Modernization of the nuclear force includes developing options to counter competitors’ coercive strategies, predicated on the threatened use of nuclear or strategic non-nuclear attacks.

The NPR affirms this by making clear that the ability to conduct nuclear strike operations below the strategic level is again ascendant in U.S. doctrine. This matches Russian nuclear thinking inferred (whether correctly or not) from open-source Russian statements over the past decade. Recognizing the likely criticism of this retrenchment, the NPR’s authors assert in its summary:

To address these types of challenges and preserve deterrence stability, the United States will enhance the flexibility and range of its tailored deterrence options. To be clear, this is not intended to, nor does it enable, “nuclear war-fighting.” Expanding flexible U.S. nuclear options now, to include low-yield options, is important for the preservation of credible deterrence against regional aggression. It will raise the nuclear threshold and help ensure that potential adversaries perceive no possible advantage in limited nuclear escalation, making nuclear employment less likely.

But far from raising the nuclear threshold, the expansion of current and introduction of new sub-strategic capabilities risks lowering thresholds and increasing the likelihood of nuclear employment in crisis or conflict.

To support these retrenchments in some NWCSs, Cold War shibboleths are being extrapolated dangerously and largely unchallenged into a very different nuclear security environment.
This article explores these shibboleths and some of the new, twenty-first-century factors that significantly complicate the execution of deterrence strategies, and if they fail, managing conflict with nuclear dimensions. It then examines an alternative approach, drawing on the deterrence policy of the UK, which places nuclear deterrence unmistakably at the strategic level and thus maintains a high threshold of use.

Dangerous Shibboleths

Even if there were a time during the Cold War when the ability to wage nuclear war contributed to strategic stability in a similar way as a strategic-level deterrent, the world today is self-evidently a very different place. This makes particularly dangerous policies, postures, doctrines, and deployments that are based on the assumption that those older precepts remain enduring nuclear truths.

Like is Necessary to Deter Like

The use of sub-strategic nuclear weapons in a conflict must, by definition, involve the pursuit of objectives beyond and below prima facie strategic nuclear deterrence. In many ways, therefore, the most hazardous of the Cold War shibboleths is that to deter across all possible circumstances a nation must always be capable of matching weapon capability and employment like for like, and must be able to fight a nuclear war at levels below the strategic one. This concept holds that to deter a nuclear ballistic missile, a ballistic missile is needed, and to deter a nuclear cruise missile, a cruise missile is needed. At the height of the Cold War, this equivalence reached down to battlefield weapons, including artillery shells.

This idea has pervaded U.S. nuclear theory, thought, and practice since the mid-1950s and is emphatically maintained in the 2018 NPR:

To correct any Russian misperceptions of advantage and credibly deter Russian nuclear or non-nuclear strategic attacks—which could now include attacks against U.S. NC3—the President must have a range of limited and graduated options, including a variety of delivery systems and explosive yields.

Throughout changing strategic circumstances, the notion that it was necessary to sustain the ability to conduct a tactical-level nuclear war was a founding principle of the U.S. nuclear triad and the main sustenance of its less-than-strategic elements. In turn, willingness to engage in battlefield or otherwise limited nuclear exchanges rested on the premise that the transition from conventional warfare to nuclear warfare could, with relative ease, be managed and that nuclear escalation could then be controlled. The clear assumption underpinning the 2018 NPR and the public pronouncements of the current U.S. administration is that such notions of escalation control remain valid.

But this assumption is especially dangerous in the twenty-first century. Maintaining and expanding lower-level nuclear options strongly risks creating a “safe space” in which nuclear weapon employment can both be easily conceived of and executed due to the perception of tolerable national risk levels. A NWCS with these capabilities risks sending an unwritten message to an adversary that there is a level of nuclear weapon employment below the strategic one that can be countenanced and, equally, that there is a level of nuclear weapon response that would not inflict upon any party strategic or unacceptable levels of damage. This message is in stark contrast to a capability and declaratory policy that retains only strategic weapons systems. The situation is particularly hazardous when the likely geographical location of any tit-for-tat nuclear use is not on the home territory of either of the involved nuclear weapon states, since any geographic restraint on responses would be significantly diminished. The risk of this would be high in the European theater in a conflict between the United States and Russia.

Nuclear Weapon Escalation Is Controllable

A nation taking the view that nuclear escalation can be controlled has lowered the threshold for use through its nuclear doctrine, capability, and posture. Such a nation must remain confident that it can manage the likely escalation following nuclear weapon employment. To achieve that escalation control, both sides need to be able to understand the aims and objectives of their adversary and have a good knowledge of their acceptable limits within the conflict. In turn, these conditions demand clear, unambiguous lines of communication between decisionmakers on each side.

Yet believers in escalation control buy into a logic that requires several courageous leaps of faith: First, that it would be possible to achieve such near-utopian conditions of knowledge and mutual understanding; second, that these conditions could be achieved and maintained during a crisis; and third, after such perfect knowledge still failed to prevent the first employment of nuclear weapons since 1945—that in the conditions of disorder, communications and data chaos induced by an electromagnetic pulse, and national and allied population panic and clamor—that such conditions could be re-established to control further escalation.

The whole concept of escalation control relies on timely and well-understood communications based on, at the very least, a shared understanding of the reality of the situation. Only if this shared understanding prevails can the antagonists transmit and receive the other’s position in such a way that nuances and shifting red lines are understood and accommodated. There can be no hope of controlling escalation otherwise.

Inter-State Crisis Communications: A Paradigm Shift

During the Cold War, the societal boundaries of what constituted the government and its position within a crisis were far clearer than they are today. Then, national media in the Soviet Union was harnessed to the government’s view, and the media in the United States was at least, for the most part, strongly behind the government’s position in its nuclear standoff with the USSR. Any government-to-government communications were managed via public speeches by the leadership and official communiques. Telegrams, public and private, and letters were signed by the president or his appropriate cabinet or Politburo representative. During crises, both indirect and point-to-point methods of communication were established, understood, and practiced. This arrangement was well suited to the largely bipolar stresses of that period.

In contrast, governments today communicate not only directly at the leadership level but also via a broad range of spokespeople with multiple and differing messages distributed through many channels. These communication channels are separately tuned and crafted with an eye toward the varying needs of the internet, television, and social media. On many occasions, these messages are conflicting and confused. More often than not, they are set in the vernacular and culture of their own country, always with an eye on the internal audience as well as that of the primary adversary. As seen recently, such communications can be extremely intemperate and escalatory in nature. In the last century, governments largely controlled the story and its public perception; today, that shared perception is under broad threat, particularly in more liberal democracies.
Beyond this most challenging problem of communication lie several complicating factors, some unique to the twenty-first century.

Complicating Factors: Miscalculation, Ethos, and Technology


One of the greatest risks to strategic stability is miscalculation in the nuclear weapons domain. Calculated acts can be deterred directly. Miscalculation, however, cannot be deterred; its likelihood can only be reduced.

The risk of miscalculation increases proportionally with the complexity and range of nuclear capabilities and associated declaratory policies and postures. A nuclear posture and capability derived from the assumption that there is a need to conduct limited nuclear war at some stage during a major conflict, and the philosophy that there is an unbroken spectrum of conflict between low-end conventional and high-end nuclear warfighting, requires the most ambiguous declaratory policies and security assurances. While ambiguity brings some deterrence benefits, it also feeds the risk of miscalculation.

In the twenty-first century, the fog of crisis (or of conflict) will likely be made more impenetrable by misinformation and cyber activities. Inflammatory rhetoric and the multiplicity of potentially confusing messages emanating from one of the nations involved will exacerbate the situation. This is a perfect setting for miscalculation.

The fear of suffering a first decapitating or disabling nuclear strike is pervasive in a crisis. It is likely that elements of less than strategic nuclear capabilities will be delivered by dual-use platforms or missiles. The possession of systems and mindsets capable of limited, less-than-strategic battlefield nuclear employment multiplies this fear through mirroring of one’s own options. The chance that a conventional attack by a dual-capable system is perceived to be a nuclear first strike increases significantly during a conflict between nuclear-capable states. Indeed, retaining dual-capable aircraft or air- or ground-launched nuclear cruise missiles, while also possessing a conventional equivalent, raises the likelihood of miscalculation in such circumstances from quite possible to near probable. If dual-capable weapons systems become stealthier, the certainty of their detection and classification would be reduced further. Doubt further increases the risk of miscalculation. Thus, of all the current and potential nuclear capabilities, the introduction of stealthy nuclear cruise missiles that can be launched from dual-capable platforms offer the greatest risk of miscalculation.


The chances of nuclear miscalculation and nuclear weapons employment are dependent, in part, on the degree to which nuclear weapons are socialized in a nuclear-capable state. The socialization of nuclear weapons correlates with the level of direct involvement of a country’s military in the planning, decisionmaking, and execution of nuclear operations. It is axiomatic in warfare that a commander will use all weapons at her disposal to ensure the survival of her forces and the achievement of her mission. Nuclear operations, if considered at all, are best considered completely dispassionately. The crew of an ICBM silo or of a ballistic missile submarine are extensions of their political leadership; they are not involved in the details of conflict or crisis. Their personal survival is not enhanced—in fact, in many cases, if not all, it will be significantly reduced—by their launching of their weapons.

The most stable nuclear deterrence relationship would be between two states that possess solely strategic ballistic missiles that, while manned by military personnel (for how would civilians be convinced to sit in a missile silo or a missile submarine for their livelihood?), are controlled by and for whom all decisions are made by the civilian political leadership. In such an adversarial situation, the leadership on both sides are well aware of the likely targets of any response to their first nuclear weapon employment, and they are thus deterred. A nuclear-capable state with high levels of military involvement in decisionmaking and execution or any expansion of capabilities with military utility on a perceived battlefield risks a lower threshold and higher likelihood of first employment than the above ideal.

I joined the Royal Navy in 1978. My first two seagoing training appointments were in Leander-class frigates, both of which carried nuclear weapons routinely. I slept within feet of the nuclear weapons storage. The continuous and permanent presence of a tactical nuclear weapon—as we went about our peacetime business of exercises, training, and port visits amid the panoply of activity in a naval warship—subtly changed the relationship that the men on board had with nuclear weapons. I would never say that it bordered on the cavalier, but it was widely and tacitly accepted that these tactical nuclear depth bombs would be the recourse in any Atlantic battle with the Soviet Northern Fleet. The level of shock and awe necessary to place nuclear weapons in the proper context had been eroded at the front line. By the mid-1990s, these weapons had been removed from the UK arsenal. The previous familiarity with nuclear weapons rapidly disappeared, and today the UK’s deterrent weapons are rightly seen throughout the armed forces and government as political weapons of extremity and last resort, as they should be.

Inculcating the belief of the inevitability of nuclear warfighting within the military and, in particular, the officer corps changes the perception that these men and women have of the utility and attraction of nuclear weapons. This risks eroding the proper stigma associated with the weapons and gradually accepting the position of nuclear weapons as simply super conventional weapons.

New and Novel Technologies

Elements of a “near-perfect storm” are assembling that threaten traditional concepts of deterrence and significantly increase the complexity of the factors involved in conflict escalation and any perceived ability to control it. These include the increasing number of conventional capabilities with strategic effects previously only achievable with nuclear means, and an emergence of relatively novel capabilities (cyber, autonomous weapon systems, weaponized artificial intelligence) that have yet-to-be fully determined effects. It is notable that the U.S. National Defense Strategy summary correctly identifies these challenges:

The security environment is also affected by rapid technological advancements and the changing character of war. The drive to develop new technologies is relentless, expanding to more actors with lower barriers of entry, and moving at accelerating speed. New technologies include advanced computing, “big data” analytics, artificial intelligence, autonomy, robotics, directed energy, hypersonics, and biotechnology—the very technologies that ensure we will be able to fight and win the wars of the future.

Yet it is strange that, aside from cyber, the NPR makes no acknowledgment of their likely impact on twenty-first-century nuclear deterrence.

In the communications space, the traditional fog of crisis and conflict is being made more opaque by data masking, psychological operations, and false environments that have asymmetric effects on democracies. The deterrence communications challenges identified above have been exacerbated by the pace of technological change to a position where it is clear that few, if any, NWCSs have adjusted their internal nuclear briefing and decisionmaking to keep abreast of this change.

An Alternative Path

Allowing some Cold War certainties to endure without serious challenge will result in postures, policies, and capabilities that risk reducing strategic stability, either through a lowering of the threshold of acceptable employment of nuclear weapons, or an increase in the risk of miscalculation. Relying on an existential gamble—the ability to control nuclear escalation—may not be the most prudent course. The nuclear weapons policies of two nuclear weapon states (the UK and, to a slightly lesser extent, France) provide signposts to a different approach that is perhaps better suited to the increased complexity of twenty-first-century deterrence. The UK centralizes its nuclear deterrence on a limited number of advanced submarine-launched ballistic missiles; France’s deterrence also rests on a similar SSBN force but it is augmented with air-launched cruise missiles for the uniquely French concept of a “demonstration strike” and to give the president “response options.” Both countries rely upon their strategic systems to deter extreme attacks against their vital national interests.

Since breaking the nuclear taboo is stepping (at best) into the unknown, it is axiomatic that the nuclear taboo should not be broken in the first place. All the policy sinews of the NWCSs should be bent to this purpose. The mere fact that a state considers fighting a nuclear war, due to necessity, after the breakdown of deterrence dilutes and diminishes the effectiveness of that initial deterrence.

It would be wiser to signal the complete unacceptability of the employment of any nuclear weapon in any circumstance. To accomplish this, it is necessary to remove as much of the nuances of calculation as possible from an adversary’s perception of the situation: they must be in no doubt of the implacable response to the employment of any nuclear weapon in crisis or conflict. There must be no space for considering an acceptable norm of tactical nuclear weapon employment. That response must be signaled by a combination of available capability, declaratory posture, and the credibility and confidence of all related declaratory statements. The indicated response must be sufficient in all circumstances to directly impact the decisionmakers in the adversary’s leadership, such that they cannot avoid the conclusion that their ability to continue to lead their country will be significantly affected by the response. I am certain that the authors of the U.S. NPR would say this is what they wrote and that this is U.S. policy, but this notion is clearly undermined by the opening of the door to sub-strategic exchanges that both leaderships might see as acceptable in the prevailing circumstances of a conflict away from their homelands.

Admittedly, the signaled response will likely be disproportionate to the potential lowest nuclear weapon employment within that conflict, especially if the adversary retains tactical warheads and delivery systems. But the signal will be directly proportional to any conceivable nuclear escalation. By clearly and unequivocally deterring that first use, this becomes an acceptable deterrence posture. Once accepted, such a posture would, over time, erode any rationale for less than strategic nuclear weapon systems.

Critics of such a position say that it is inherently self-deterring and that an adversary may calculate that you would not react to a small nuclear weapon employment, with relatively limited effect, with such a strictly disproportionate response. This is a seductive argument, and it justifies a return to a diverse warfighting-capable nuclear arsenal, but the reasoning is fallacious. It is not necessary that an adversary must be 100 percent certain you will respond as you indicate, but the unacceptable nature of the damage he risks incurring means that he must be 100 percent certain you will not retaliate before he decides to break the taboo.

Any lesser or variable response, far from enhancing deterrence, reduces the threshold for nuclear use and increases the possibility of nuclear weapon employment in an escalating conventional conflict. All responsible NWCSs must keep under continuous review their declaratory policies, capabilities, and postures against the benchmark of maintaining or improving strategic stability.

As a secondary and subsequent effect, once accepted, such a posture would over time erode any rationale for less than strategic nuclear weapon systems. It would facilitate progress toward a more stable, strategic worldwide deterrence based on solely strategic systems. And it would permit—if political conditions are ripe—more realistic multilateral discussion on fulfilling the NPT Article VI requirement for good faith negotiations on disarmament.


John Gower is a retired rear admiral from the Royal Navy with thirty-six years’ service. His last six years in service were spent in the UK Ministry of Defence, responsible for policy advice and formulation on countering weapons of mass destruction, arms control, and counterproliferation and particularly UK and NATO nuclear weapons policy. He now works as an independent consultant.


1 Introduced in this article, the term nuclear-weapon-capable state (NWCS) is designed to include the five permanent members of the UN Security Council as well as India, Israel, and Pakistan.

2 The Treaty on the Prohibition of Nuclear Weapons is “materially ineffective and unrealistic” in the sense that it has no prospect of binding the very nations it needs to be effective.