Analysis & Opinions - Foreign Affairs

The Age of Strategic Instability: How Novel Technologies Disrupt the Nuclear Balance

| July 21, 2020

For decades, American policymakers and military planners have focused on preserving what is known in the nuclear lexicon as “strategic stability.” During the Cold War, especially as mutual assured destruction became accepted logic between the United States and the Soviet Union, the pursuit of strategic stability provided a framework for managing the existential risks associated with massive nuclear arsenals. Under conditions of strategic stability, each superpower recognized that its adversary could massively retaliate against a nuclear first strike—which created a disincentive to resorting to nuclear weapons. Preserving confidence that each side had a “second-strike capability” thus became essential. And even with the collapse of the Soviet Union in 1991, strategic stability has continued to structure thinking among policymakers and planners about how to create predictability in the nuclear relationship and reduce incentives to escalation.

Yet as the quest for strategic stability has continued to guide defense planning and arms control, it has become increasingly untethered from technological and geopolitical realities. Since 2011, tensions have been mounting in the U.S.-Russian relationship, giving rise to the very real possibility that some combination of deliberate actions, misunderstandings, miscalculations, and accidents could lead to nuclear escalation and catastrophe. After several decades of rules, agreements, norms, and human relationships fostering prudent behavior and shrinking nuclear arsenals—from the Cold War peak of more than 70,000 warheads, each side now retains between 6,000 and 6,500—arms control is being undermined and abandoned. Last August, U.S. officials withdrew from the Intermediate-Range Nuclear Forces Treaty, in reaction to evidence of Russia’s noncompliance. In May, U.S. President Donald Trump announced his intention to withdraw from the Open Skies Treaty (which has allowed unarmed observation flights, in order to enhance transparency). The sole remaining U.S.-Russian agreement is New START, which limits the aggregate number of strategic offensive arms in each arsenal—and if that is not renewed in early 2021, it too will collapse. Meanwhile, new technologies are presenting their own challenges to long-standing thinking about escalation.

Accordingly, the traditional focus on strategic stability may no longer be sufficient to manage today’s risks. Even with the resurrection of arms control agreements now being abrogated or dismantled, there is reason to doubt that strategic stability, at least as understood in the old paradigm, could be reestablished or preserved.


To fathom the unprecedented nature of the challenges ahead, it is important to understand the logic that governed classic strategic stability—a logic driven by the imperative of discouraging escalation between two nuclear-armed superpowers. In this construct, both the United States and Russia (or, until 1991, the United States and the Soviet Union) believed that the other side lacked the capacity to threaten the “survivability” of its nuclear forces: each knew that after a nuclear attack, it would still have sufficient nuclear warheads and delivery systems (and the command-and-control network necessary to launch them) to retaliate. As a result, each side retained confidence that its second-strike capability would be preserved. This mutual recognition created a disincentive to strike first, since both Moscow and Washington knew that any nuclear attack would be met with a nuclear response—thereby maintaining a perilous but thus far real equilibrium. 

That long-standing logic has been upended by new technologies and the spread of competition to new domains. For nuclear strategists of an earlier era, whatever the exigencies of calculating throw-weight, first- and second-strike capabilities, and missile ranges, the basic considerations were relatively simple: there was a fairly linear escalation ladder from conventional to nuclear weapons, with just two players involved. Policymakers and defense planners today have to contend with a system of complex interactions that are far less predictable and therefore harder to manage or control. Preserving stability and avoiding escalation become exponentially more difficult in this environment.

The United States can play a major leadership role in both reducing tensions and building new norms.

There is now a broader array of capabilities that can be considered “strategic”—meaning that their use can have consequences significant enough to potentially impair or disable the target’s ability to respond effectively and thereby to deter aggression. Once, this was the unique purview of nuclear weapons. Now, advances both in nuclear weapons and their means of delivery and in other technologies and capabilities create new uncertainties that undermine deterrence and potentially create incentives for escalatory behavior.

On the classic nuclear front, Russia is working to achieve prompt, penetrating, and precise strikes on distant targets. This effort involves work on heavy intercontinental ballistic missiles, multiple hypersonic delivery systems, and novel weapons delivery capabilities, such as a nuclear-powered, nuclear-armed underwater drone. The Chinese nuclear arsenal is considerably smaller but also expanding and will benefit from China’s investments in advanced technologies with military applications.

Beyond nuclear, cyberspace is the realm that has garnered the most widespread public attention thus far. Cyberspace is both a warfighting domain and a capability that can be deployed in other domains. With respect to strategic stability, cyber gives adversaries the ability to disable a country’s way of life by stealthily attacking its “soft underbelly” rather than by using classic, observable military capabilities. U.S. policymakers and strategists have begun discussing whether the United States should threaten a nuclear response to a debilitating wide-scale attack on energy infrastructure, with the goal of deterring any such attack. Adding this to the list of casus belli for nuclear response could serve as a deterrent, but it would also open up a new escalatory pathway without clear firebreaks. 

Space has also become a contested domain, with similarly worrying implications for strategic stability. Space capabilities are integral to enabling or disabling critical capabilities in other domains; satellites, for example, are essential to both military and civilian communications, and adversaries have targeted them in order to challenge U.S. dominance. American defense planners are wrestling with the implications for deterrence and stability: what if, for example, U.S. satellites that provide early warning of missile launches were damaged or disabled?

Biotechnology is another area with potentially strategic implications. Innovation has spawned new capabilities that have enormous positive potential, especially in advancing health science and generating new therapeutics for the prevention and treatment of a wide range of diseases. However, these developments also have a darker side and could be weaponized with potentially strategic effects. At the end of 2016, the President’s Council of Advisors on Science and Technology offered a warning: “While the ongoing growth of biotechnology is a great boon for society, it also holds serious potential for destructive use by both states and technically-competent individuals with access to modern laboratory facilities.” For example, if a deadly virus was discovered to have been engineered and conveyed to a specific country, would that be interpreted as a strategic attack that would warrant a strategic response? There is no established logic to a reality in which new technologies can have the kind of existential impact that was once unique to nuclear weapons. 


The development and interplay of these new capabilities present significant challenges to policymakers and defense planners whose training and experience have been based in linear nuclear strategizing. At the moment, some of the most forward-looking thinking is taking place in U.S. military organizations charged with ensuring the nuclear deterrent and facing the practical, operational challenges presented by emerging adversarial capabilities. General John Hyten, then commander of U.S. Strategic Command and current vice chairman of the Joint Chiefs of Staff, observed in 2017, “It’s now a multipolar problem with many nations that have nuclear weapons, . . . and it’s also multidomain. . . . We have adversaries that are looking at integrating nuclear, conventional, space and cyber, all as part of a strategic deterrent. . . . We can’t [assume] that having 1,550 deployed strategic nuclear weapons under the New Start Treaty somehow deters all our adversaries. It doesn’t.”

A useful framework for taking stock of this new reality comes from work on understanding the behavior of complex adaptive systems (CAS). A complex adaptive system is a system that is inherently anarchic, lacking in central control or coherent governance. Yet its elements interact and impact one another and the entire system. Originally developed to model systems that defied computer-based simulation, CAS evolved to anticipate heterogeneous and often multidimensional system dynamics in a broad range of contexts.

Some key characteristics of complex adaptive systems are especially relevant to a warfighting environment. They involve interactions between or among asymmetric capabilities, and what happens at the level of the entire system cannot necessarily be predicted by the nature of the components of that system. This means that understanding the dynamics of nuclear escalation will not necessarily allow a decision-maker to understand what happens when nuclear, cyber, and biological threats interact. In addition, the response of a system to a specific input may be disproportionate to that input, which makes outcomes unpredictable. In a conflict, what one side perceives to be a limited, measured action might have an outsize effect, leading to misinterpretation and escalation.

Altogether, it has become far more difficult to predict behaviors, interactions, and outcomes. With more and new players, domains, and capabilities, and no rules of the road governing usage, classical notions of strategic stability offer scant guidance. Deterrence now has to work across a much broader and more complex landscape. And less predictability can lead to preemptive behavior, with catastrophic consequences, and more hedging, which can accelerate arms races, as nations seek confidence that their own interests are protected when adversaries field new weapons.


Accordingly, simply returning to traditional arms control will be far from adequate to address the dangers of today’s and tomorrow’s realities. Arms control among the major nuclear powers should remain a goal, but policymakers will also have to enlarge the problem set in order to effectively address the interplay of existing and new capabilities.

The United States can play a major leadership role in both reducing tensions and building new norms. U.S. strategists and planners need to undertake a broad and integrated effort to develop a framework for synchronizing deterrence across multiple platforms—and for developing a related framework that addresses the implications for strategic stability. This will require working through a wide range of scenarios and exploring multiple escalation pathways, and doing so in coordination with allies in order to build confidence and predictability and avert preemptive escalatory behavior in a far more dynamic environment. 

Washington should also try to start a new high-level dialogue with Moscow about strategic stability, despite the current state of the U.S.-Russian relationship. During other tense moments in the past, nuclear talks have helped reestablish predictability, created a check on arms racing, and ultimately enabled each to be confident that it had adequate capabilities to hold the other at risk, which discouraged escalatory behavior and preemptive first strikes. At times, such conversations have even succeeded in persuading both sides to reduce their reliance on nuclear weapons. If government-to-government relations are too fraught to begin these discussions, Track II dialogues could be used to generate initial options.

China poses a very different challenge. While the United States and Russia retain the world’s largest nuclear stockpiles and have decades of experience in managing their strategic competition, China has an estimated arsenal in the low couple of hundreds. Given the substantial asymmetry in the nuclear domain, the focus with China must be on the growing competition for the technology edge in many of the new strategic domains identified here, including cyber, space, and bio, and in the enabling technologies of future warfare such as artificial intelligence and quantum computing. In order to avoid future arms racing that mimics the madness of the height of the Cold War, the United States and China should begin a serious exchange about establishing guardrails and potential constraints on the most destabilizing capabilities. 

The United States and other countries with substantial strategic arsenals bear a unique responsibility for managing these new geostrategic and technological realities. Over time, dialogues among leading powers about the range of new capabilities could produce a comprehensive and integrated view of the battle space that enables thorough consideration of interactions that are possible across multiple domains. If sustained by determined leadership and informed by science, these processes could eventually lead to the creation of a more stable overall balance. 

As anyone who has taken part in U.S. strategic exercises knows, the timeline for making decisions about launching nuclear weapons in an actual crisis would likely be very short, with inadequate information and immense pressure to act. Given the proliferation of new warfighting tools with strategic effects, American leaders now have to consider even more complex conditions—and yet still find ways to manage uncertainty, reduce the risks of miscalculation, and strengthen incentives for rational behavior and restraint. Only by doing so, and working to develop common understandings with allies and adversaries alike, can they reestablish confidence that they can avert escalation that may otherwise engulf the world.

  – Via Foreign Affairs.

For more information on this publication: Belfer Communications Office
For Academic Citation: Sherwood-Randall, Elizabeth.“The Age of Strategic Instability: How Novel Technologies Disrupt the Nuclear Balance.” Foreign Affairs, July 21, 2020.