Give Instability a Chance?


Technology and politics are conspiring to make the world dangerously unstable. The result: War and nuclear escalation are becoming more likely. These are the summary conclusions of a diverse group of scholars and policymakers who offer a grim list of reasons why stability is vanishing.

Advances in sensors and weapons make disarming counterforce strikes more tempting than ever. The threat of assured retaliation, which may have injected a dose of caution among those considering a preemptive attack during the Cold War, is disappearing. At the same time, the rapid spread of disinformation may lead to confusion and unpredictability during crises, as carefully crafted government signals give way to ad hoc tweets. New technologies blur the line separating conventional and nuclear weapons and create opportunities for weaker states and non-state actors. In this environment, as one Obama administration official recently put it, “classical notions of strategic stability offer scant guidance.”



The peculiar technological characteristics of cyberspace make everything worse. Military forces have spent years centralizing communications to maximize efficiency, but in so doing become more vulnerable to crippling information attacks. Nuclear command-and-control networks are similarly attractive targets for leaders seeking to disable enemy nuclear capabilities. Offensive cyber operations rely on secrecy to succeed, but this undermines deterrence, which requires that adversaries advertise their forces. The result is a powerful incentive to get the first shot in, whether in cyberspace or the real world.

Some analysts offer the potentially hopeful reminder that politics, not technology, drives decisions about the use of force. Innovation may have important social and political consequences, but it does not cause war. If international politics are sedate, war is unlikely and nuclear war is unthinkable. Unfortunately, today’s politics are defined by a series of deepening conflicts among existing and aspiring nuclear powers. Great powers are competing. Regional conflicts are becoming more hostile — and more violent. Status quo nuclear states are opting for “maximum pressure” against those they suspect of wanting to join the club. And the political agreements that have anchored arms control for decades are coming apart.

But not everyone is worried about instability. The U.S. nuclear force posture, in fact, seems to be based on the idea that a little instability can go a long way.

Optimum Instability

This counterintuitive idea has a long history. Cold War leaders never accepted the idea that deterrence flowed from mutual vulnerability, and they spent years trying to gain an edge. Some analysts argued that deterrence only worked if states could reduce damage in a hypothetical nuclear exchange. Who, they asked, would take “a threat to commit suicide” seriously? Moreover, perfect stability at the nuclear level might encourage conventional war: If states had no fear of escalation, they would be more willing to use force at lower levels. Somewhat paradoxically, these analysts argued that instability was a force for peace. Leaders needed to believe that a nuclear war was possible to be scared of starting one. Instability — the notion that there is no insurmountable firebreak separating conventional and nuclear war — would also force leaders to be cautious in a crisis. According to this school of thought, then, instability deterred conventional war and prevented intra-war escalation.

We are left with two opposite views of instability. The first warns that it encourages misperceptions and fear, with dangerous and unpredictable consequences. The second argues that instability is necessary and good, because deterrence is impossible if leaders believe they have nothing to fear.

Lying between these two claims is the notion of “optimum instability,” an idea that first appeared in a relatively obscure RAND Corporation report near the end of the Cold War. Optimum instability obtains when adversary leaders believes that their nuclear forces are just a little insecure. The goal is to generate enough instability to influence their behavior, but not so much that they will lash out in fear and frustration. It’s a “goldilocks” approach to coercion: Too little instability will encourage conventional aggression, but too much will invite disaster. Unlike the first school described above, it celebrates the benefits of instability. Unlike the second school, it is cognizant of the risks.

Optimum instability deters crises by disabusing rival leaders that they can act with impunity under the cover of nuclear weapons. Putting their arsenals at risk forces them to reconsider the value of whatever policy goals they seek. This may be particularly important for emerging nuclear powers that have outsized expectations of what their new weapons can provide. But it also injects caution in established nuclear powers by hinting that their large and variegated arsenals are not completely invulnerable. In this sense, it reverses the stability-instability paradox.

Ideally, optimum instability would force adversaries to shift to the defense, nudging them toward costly investments that stress their economies. It would also promote bureaucratic friction by forcing adversary organizations to scramble, encouraging nasty infighting among sharp-elbowed but thin-skinned officials whose ideas for defense have proven unsatisfactory. Ultimately, it would force rival leaders to question their own grand strategy. They may determine it is unsustainable.

In addition to these effects on adversary behavior, optimum instability would help manage alliance politics by making deterrence commitments credible and reducing allies’ need for their own nuclear arsenals. It pulls off something that at first glance seems paradoxical, demonstrating the coercive value of nuclear weapons while simultaneously convincing allies they are not worth having.

The Trump administration calls for strategic stability, but its nuclear posture suggests something different from the traditional meaning of the term. For nuclear analysts, crisis stability means that neither side has an incentive to strike first, because assured retaliation would lead to mutual disaster. For the Trump administration, however, stability is a function of superiority, and deterrence requires limiting damage through a combination of counterforce strikes and missile defenses. Adversaries must remain somewhat uncertain about the course of events in a crisis, or else U.S. deterrent threats will ring hollow. President Donald Trump himself has embraced this idea, which aligns with his basic view of business: “You want to be unpredictable.”

If optimum instability makes adversaries cautious, it also strengthens extended deterrence and relieves allies of the need to go nuclear. In this sense, the administration’s language has echoes of U.S. policy at the height of the Cold War. President John F. Kennedy unveiled the doctrine of “flexible response” in 1962 in order to convince NATO allies that the United States had practical options for fighting the Soviet Union. At the time, critics questioned whether threats of massive retaliation were credible when U.S. security was not immediately at risk, and the Kennedy administration sought language that could convince allies that it could respond in ways that did not invite Armageddon. The purpose was managing alliance politics, not fundamentally changing the U.S. approach to warfighting.

The Trump administration also seems to believe that a broader nuclear strategy, which anticipates a number of different contingencies, will help keep proliferation in check. As the 2018 Nuclear Posture Review declared, “the United States will maintain the capabilities necessary to deter effectively and, if necessary, to respond effectively and decisively across the spectrum of potential nuclear and non-nuclear scenarios.” Making credible threats in non-nuclear scenarios requires investing in conventional counterforce weapons, which would allow the United States to strike first without breaking the nuclear taboo. It may also explain the reported White House interest in cyber-attacks against rival nuclear command-and-control networks, despite warnings from analysts that these are especially destabilizing.

How Much Instability Is Enough?

As with other aspects of Trump’s nuclear policy, these ideas long predate the current administration. Indeed, the logic of optimum instability informed U.S. nuclear targeting policy going back to at least the 1970s, though the term came later. Efforts to develop plausible nuclear warfighting strategies also contributed to nonproliferation, because they helped convince NATO allies that U.S. extended deterrence was credible. While Trump’s rhetoric seems outlandish, the essence of current U.S. nuclear strategy is much the same. Ongoing investment in all three legs of the nuclear triad as well as the president’s outspoken commitment to thinking the unthinkable are signals that Washington is betting on instability. Whether its confidence is justified is another matter.

Indeed, there are some knotty questions lying under the surface of all this optimism. One is whether it is possible to locate the optimum point. The logic is conceptually straightforward but difficult, and perhaps impossible, to implement with any kind of precision. Doing so will require not just creating the right amount of uncertainty among foreign leaders, but being able to assess their perceptions accurately in real time. This is a tall order.

A second question is whether it makes sense to think of an adversary state as a unitary actor, or as a constellation of officials and bureaucrats with their own goals. Optimum instability in the former case rests on an appeal to rationality. If the adversary is less sure of his second strike, it will become cautious and shift to the defense. But the latter case rests on the idea of injecting friction into the adversary’s political system and defense organizations. It creates disunity and irrationality. It is worth asking if these logics are mutually exclusive. That is, is it possible to use instability to influence another state’s rational judgment, when the act itself introduces irrational forces into its decision-making process?

A third question is whether optimum instability is a function of force posture, declaratory policy, diplomatic interactions, leadership psychology, or some messy combination of these factors. The RAND study that introduced optimum instability focused on the balance of forces. Military planners will pay close attention to the balance (and for good reason). But civilian policymakers are more likely to rely on their own beliefs about adversary intentions, and this will affect their approach to peacetime and crisis bargaining. So, we could end up in a situation in which instability has different impacts on different kinds of adversary behavior. Instability may have optimum effects on adversary long-term defense investment — a domain where military experts hold sway. But it may have suboptimal effects in crises, where leaders are forced to make critical decisions under stress.

Finally, when do the benefits of optimum instability exceed the risks? As with all competitive strategies, the deliberate pursuit of instability might make sense against some adversaries but not others. Determining the wisdom of this approach depends on technical and political factors. As Austin Long points out, the United States must have the forces to prevail in a hypothetical conflict, or at least convince adversary leaders that this is possible. Adversaries with large, dispersed, and well-protected forces are poor targets. Political dynamics also restrict the opportunities to control and exploit instability. Leaders who are relatively secure can safely back down in the face of threats, but leaders who fear internal enemies may be insensitive to foreign pressures. Worse, they might choose to escalate as a way of consolidating their own power, playing on nationalism to rally support at home. Creating instability in these cases would probably be counterproductive.

Because a favorable balance of forces must align with specific political conditions, optimum instability will only succeed in rare circumstances. Ideally, policymakers will know when to exploit instability, and when to embrace restraint. They will also need the political courage to walk away from an aggressive approach. In the face of sustained calls for great-power competition, this may prove most difficult of all.



Joshua Rovner is associate professor in the School of International Service at American University.

Image: U.S. Air Force photo