One paradox of nuclear deterrence has always been that whatever utility the Bomb provides is lost once the nuclear threshold is crossed, however large or small the boom. There is no bigger blunderbuss than a nuclear weapon atop a long-range missile. Smaller-yield message-senders have been created in the form of tactical nuclear weapons, but any advantageous battlefield use of nuclear weapons against a similarly armed foe requires heroic assumptions. Basic nuclear deterrence is measured by non-use. The derived benefits of “strengthening” deterrence by means of more discriminating or improved methods of delivery have been completely conjectural.
How much of a deterrent is a weapon that hasn’t been used on battlefields for almost 70 years? Deterrence strategists object to this formulation. They argue that, even without mushroom clouds, the Bomb has leveraged favorable outcomes in diplomacy, crises and wars. These arguments do not withstand close scrutiny. The Bomb has indeed energized diplomacy to defuse crises – after exacerbating them. It has also reinforced the common sense of major powers not to fight full-blown conventional wars. Beyond reinforcing caution, the Bomb’s suasion is limited. It can’t override bad national decisions, local circumstances, and differentials in commitment to achieve preferred outcomes. The Bomb hasn’t proven its worth when nuclear-armed states square off against non-nuclear-weapon states, as is evident by a painfully long track record of conventional wars, limited wars, proxy wars and unconventional wars.
The quest to fine-tune deterrence to increase leverage above and below the nuclear threshold is nonetheless an endless project. As missile accuracies improved and warheads multiplied, thanks to MIRVs, targeting lists grew. Limited and not-so-limited options were added to massive targeting plans in the quest for leverage, advantage, or war-winning capabilities.
Deterrence benefits from limited nuclear options are based on two dubious presumptions — that escalation can be controlled and that an adversary will not skip rungs on the escalation ladder. Mental gymnastics have always been required to derive deterrence benefits out of plans for massive retaliation.
In the 1990s, the advent of precision-strike conventional capabilities promised greater diplomatic leverage and militarily effectiveness without crossing the nuclear threshold. But air power alone has always had limited effectiveness and suasion. “Prompt global strike” and hypersonic weapons are now advanced in the pursuit of more discriminate, effective deterrence. Their promise also rests on risky assumptions – that strikes will not mistakenly hit nuclear-armed or related targets, and that a foe will accept attrition without crossing the nuclear threshold.
Fred Iklé and Albert Wohlstetter led a study on ‘Discriminate Deterrence’ at the end of the Reagan administration. Their Commission on Integrated Long-Term Strategy report was released in January 1988. Contemporary readers will find no hints in this report that the Soviet Union, against which the Commission’s recommendations were primarily directed, was a house of cards. One example: “We will seek to contain Soviet expansionism in any region of the world.”
The Commission predicated its recommendations on this key finding:
To help defend our allies and to defend our interests abroad, we cannot rely on threats expected to provoke our own annihilation if carried out. In peacetime, a strategy based on such threats would undermine support for national defense. In a crisis, reliance on such threats could fail catastrophically for lack of public support. We must have militarily effective responses that can limit destruction if we are not to invite destruction of what we are defending.
How, then, to proceed? Here are some excerpts:
We must diversify and strengthen our ability to bring discriminating, non-nuclear force to bear where needed in time to defeat aggression. To this end, we and our allies need to exploit emerging technologies of precision, control, and intelligence that can provide our conventional forces with more selective and more effective capabilities for destroying nuclear targets…
We and our allies would rather deter than defeat an aggression, but a bluff is less effective and more dangerous in a crisis than the ability and will to use conventional and, if necessary, nuclear weapons with at least a rough discrimination that preserves the values we are defending…
The precision associated with the new technologies will enable us to use conventional weapons for many of the missions once assigned to nuclear weapons. The new technologies will work to strengthen the ability of our ground and air forces to defeat invasions. Particularly important in this connection is the prospective use of “low observable” (Stealth) technology in combination with extremely accurate weapons and improved means of locating targets. In the years beyond 2000, this combination will provide new ways to stop invading forces at great distances from the front lines.
Iklé and Wohlstetter were prescient in forecasting that the United States would pursue precision strike conventional capabilities, low observables, and replacing nuclear for conventional weapons against certain targets in strategic war plans. Even so, the U.S. track record of deterrence, dissuasion and compellence during the past quarter-century has not merited high marks. The awesome powers of nuclear weapons are greatly compromised in the real world. Diversified and more discriminating capabilities do not help when leaders and their followers are not amenable to deterrence. In these instances, what matters most is maintaining a firewall between nuclear and conventional capabilities.
Michael Krepon is Co-Founder of the Stimson Center. This piece originally ran in Arms Control Wonk on February 18, 2015.