The appeal, and folly, of minimum deterrence

The current nuclear disarmament debate in the United States has been given an unusual twist by a group of US Air Force officials and academics who reject the goal of elimination but argue for radical, and unilateral, reductions in the US nuclear arsenal.

To say that elements within the US Air Force are calling for radical nuclear reductions is, if anything, an understatement. In the current issue of Strategic Studies Quarterly,[i] two Department of Defense academics and a serving Air Force Colonel argue for a nuclear deterrence strategy based on an arsenal of 311 deployed nuclear warheads – 100 on land-based missiles (ICBMs), 195 on submarine-based missiles (SLBMs), and 19 on bomber-based cruise missiles (ALCMs).

In reaching that conclusion, however, these Air Force analysts explicitly reject the vision of a world without nuclear weapons and mount a spirited defence of the enduring benefits of nuclear deterrence and the weapons that deliver it.

Stability in a competitive international environment is preserved to a significant degree by deterrence – that is, an adversary is dissuaded from taking certain destabilizing or aggressive actions by the promise that unacceptable damage will be visited on it in response. Thus, as the Air Force analysts put it, general deterrence policy is designed “to ensure that incentives for aggression never outweigh the disincentives.”

Most states, most of the time, abjure aggression because of persuasive incentives to respect the sovereignty of other states – that is, they benefit from a stable world in which their rights as states are respected and in which military aggression is the rare exception. At the same time, most states also maintain conventional forces to add disincentives – that is, to assure their neighbors and adversaries that aggression would incur costs.

And the most persuasive disincentive or threat is, obviously, the threat of nuclear attack – “nuclear weapons socialize statesmen to the dangers of adventurism,” say the Air Force analysts. Hence, the main thrust of their argument is to support the maintenance of a nuclear deterrent for the long-term foreseeable future. And, they add, it needs to be only a minimal deterrent – a few hundred warheads are capable of delivering all the threats needed to persuade or dissuade any adversary.

But then they add a caveat: “…because the adversary will discount these threats by its assessment of the likelihood that the deterrer will implement them, the deterrer must convey these threats credibly.” In other words, that puts us pretty much back where we were in the Cold War when the Americans and Soviets went to insane lengths (in excess of 70,000 warheads) to demonstrate the credibility of their deterrent.

Credibility isn’t just a minor problem for nuclear deterrence – it is a central characteristic of deterrence and renders it intrinsically unstable.

The Air Force analysts say that nuclear weapons are sufficiently credible to “virtually preclud[e] acts of aggression against states that possess them, and thereby greatly enhance stability.” But that ignores two fundamental, and rather obvious, problems – both of which signal instability.

First, the scenario posits a nuclear state threatening a non-nuclear weapon state, even though nuclear weapon states have since 1996 formally agreed to “negative security assurances” – that is, the explicit commitment never to use or threaten to use nuclear weapons against non-nuclear weapon states. They make that promise because it is in their interests to do so, and it is in their interests because it is an essential requirement for non-proliferation. If nuclear weapon states issue nuclear threats against states without nuclear weapons, the latter have only two credible options – either become aligned with another nuclear weapon state and thus find solace (and dependence) under its umbrella, or work hard to acquire an independent nuclear deterrent for themselves. Nuclear threats against non-nuclear weapon states produce incentives to proliferate – the opposite of stability. That is why the US is seriously considering the inclusion of a “sole purpose” pledge in its forthcoming Nuclear Posture Review – a pledge that the sole purpose of nuclear weapons is to deter their use by other states. And it is also why non-nuclear weapon states have been demanding that negative security assurance be changed from national declarations to legally-binding international agreements.

So, it is the absence of nuclear threats that contributes to non-proliferation stability. Nuclear deterrence against non-nuclear weapon states creates proliferation incentives and is therefore inherently unstable.

Second, if a nuclear weapon state is in confrontation with another nuclear weapon state, the use of a nuclear weapon – that is, actually carrying out the deterrent threat – would obviously be suicidal because it would trigger a response in kind. Whether it is minimum or maximum deterrence, there is no getting around MAD, mutually assured destruction. That fact obviously undermines the credibility of the deterrent (why would you use it if the guaranteed result was your own destruction?). That in turn creates the perceived need to make the deterrent more credible – by making it bigger, by improved accuracy for counterforce threats to take out large elements of the other side’s weapons to reduce its retaliatory capacity, by ballistic missile defence systems which are also designed to reduce the capacity to retaliate and thus enhance the threat of first use. These moves are then obviously mimicked by the other side. In other words, there is no stability – only the chronic instability of innovation and counter-innovation, otherwise known as an arms race.

Nuclear arsenals are anything but stable. They follow trajectories. In the Cold War it was an escalating trajectory, since the end of the Cold War it has been a descending trajectory. But there are already signs of reversal. China is modernizing. US missile defence is producing escalatory pressures in Russia. Pakistan and India, both declared devotees of minimum deterrence, have not found stability and are both busily building up their arsenals and their stocks of fissile materials. Israel’s refusal to open its nuclear facilities to international inspections continues as a major impediment to consensus within the Nuclear Non-Proliferation Treaty review process. States without nuclear weapons in that region are looking to give themselves nuclear options – and the greater the perception that more states, like Iran followed by other Arab states in the Middle East, will acquire the capacity to go nuclear, even if they don’t immediately do so, the more difficult it is to build the political will for radical reductions in nuclear weapon states.

The call by analysts linked to the US Air Force for radical and unilateral reductions in the US arsenal to 311 deployed warheads is a welcome call to continue the current nuclear trajectory on a downward path. At the same time, even minimum deterrence will not serve long-term stability. Deterrence is not a stable condition – the only credible basis for stability is the one envisioned in the Nuclear Non-Proliferation Treaty, namely, the elimination of all arsenals, backed by a verification system capable of giving credible, long-term assurances that all states are in full compliance.


[i] James Wood Forsythe Jr., Col. B. Chance Saltzman, and Gary Schaub Jr. “Remembrance of Things Past: The Enduring Value of Nuclear Weapons,” Strategic Studies Quarterly, Spring 2010, pp. 74-89.

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