Over the next 25 years or so, the United States plans to recapitalize its triad of submarines, bombers, and missiles that deliver strategic nuclear weapons, building new versions of these weapons to extend a 50-year-old force structure for another half century. Yet today’s strategic environment is not that of the 1960s, and tomorrow’s may differ even further, if only because of regional nuclear powers and non-state adversaries. Are the challenges of that environment best met by replicating, presumably with fewer weapons, a force structure intended to survive, at least in part, a massive Soviet attack? And is the thinking that produced the earlier plans the best way to approach future challenges?

A Hope, Not A Plan
The central concept underlying the current force structure, of course, is deterrence, an aspiration embraced in the nuclear era as a default option imposed on military planners by weapon technologies. Unable to prevent a comparably-armed enemy from destroying the United States, Americans could only hope to avoid being disarmed. What the surviving weapons would be used for is the subject of presidential guidance and has long been debated, but the ability to retaliate, whatever the targets, was thought to provide the best achievable response to mortal threats.

The threat to use nuclear weapons, however, proved difficult to extend when the challenges were less than immediate and dire. If invoked to deter minor harassments, the threat of massive retaliation would seem almost risible, defying the perceptual conventions of proportionality and connectedness. And if the possession of nuclear weapons by the U.S., the only country to have used atomic weapons in war, posed an implicit threat, it was not enough to preclude problems of flexible response, compellance, escalation, and conflict termination.
Whether tests like these might be deterred in the future has become a popular question.

Seminars, workshops, conferences, and interagency working groups have been considering how deterrence might be pursued to forestall land, sea, air, space, and cyber threats. At least one panel of a forthcoming conference, for example, asks not how deterrence might help the U.S. with recent developments in the Middle East but rather what those developments might tell us about deterrence. And to a former commander of Strategic Command the policy primacy of the concept was unquestioned: “The concept of deterrence is sound,” he wrote, “and we have the means necessary to implement it against the full range of threats that are reasonably susceptible to deterrence.

The challenge that remains before us is to allocate the resources and create the processes necessary to proactively and successfully ‘wage deterrence’ in the Twenty-First Century” (Strategic Studies Quarterly, Spring 2009). Also of note in this regard is the recent emphasis in defense policy on the alleged deterrent effects of entangling U.S. security programs with those of other countries, in the hope that common interests could be fertilized and would-be aggressors confronted with a larger status quo coalition. Over the past year, for example, various Pentagon leaders have urged that we replace half the GPS constellation with the satellite navigation systems of Europe, Russia, and China, and that we design and operate spy satellites jointly with allies.

But deterrence is an emergent property of circumstances that are often quite complicated and only partly known, and is correspondingly difficult to use as a general guide for planning. The search for meaning is further frustrated by the recourse to accounting-style tautologies about balances of costs and gains, risks and rewards, and by simplistic models portraying only military threats between two unitary actors who experience payoffs or outcomes determined by the product of coherent strategic choices decided on the basis of expected-value maximization. The inability to specify critical values and relationships a priori makes these approaches vacuous (see, for example, the Department of Defense, “Deterrence Operations Joint Operating Concept,” Version 2.0, 2006).

Nor is much planning guidance to be gained (yet, at least) from historical research. As a practical matter, it has been virtually impossible to show who was deterred from what and why. Credible information is practically never available in the detail required to characterize the actors, interests, perceptions, decisions, and expected outcomes well enough to prove cause and effect. Lack of such proof invites simple logical errors of the lurking post hoc fallacy together with potentially dangerous misperceptions of how arms and influence might transpire in particular circumstances. Similar problems challenge nearly every attempt to pursue policies and programs aimed at creating deterrence, whatever the type or degree of analytical complexity, owing to a shared morphological paradox: adversary expectations are (a) the central focus and measure of merit for policies and programs, while they are (b) characterized almost exclusively by introspection and a priori speculation. Projective psychology is the essence of deterrence policies, and the temptation can be overwhelming to sketch the adversary in ways that best accommodate the options that one is most inclined to pursue.

Empirical data can help, of course. Post mortems of challenges that occurred even before the nuclear age can increase awareness of the possibilities of surprise, of how things can go wrong, of the merits of different styles of leadership and decision-making and crisis management. But the lessons for deterrence are inevitably situation-specific. Should commitments be expressed or implied, unbending or flexible, defined early or later? Should responses be automatic or subject to decisions at the time? Does having a range of capabilities undercut or increase the credibility of the threat? History answers these and related questions with Yes and No.

Moreover, even when empirical data about adversary views and calculations are unambiguous, they may have little to do with structuring the policies and programs intended to create the conditions for deterrence, even when the stakes are extremely high. The U.S. did relatively little, for example, to make its nuclear posture score highly in the warfighting terms with which the Soviet Union assessed the correlation of forces; the introduction by Secretaries Schlesinger and Rumsfeld of limited strategic options was opposed by many Americans who feared that the policy would make nuclear weapons more usable. This chronic tension between making the force credible but usable only in extremis clearly illustrates that the pursuit of deterrence as a practical matter can only be determined by the situation at hand. “Tailored deterrence” is a redundancy.

If You Want Peace . . .
Deterrence, in sum, can be a desirable goal but an impossible guide. In pursuing it the country is seeking security through a concept that requires unavailable data about unknown processes, that is not empirically testable, and that cannot be shown to be working. In practice, American interests are often challenged by an adversary doing something that we want to stop or reverse. Such compellance tasks are different analytically and operationally from deterrence, and deterrence postures, which enshrine responses to the initiatives of others, may be poorly suited to managing them.

Moreover, deterrence logics can encourage second-order effects that undercut preparations to fight and win wars. American policy has long insisted on a force posture that encourages deterrence, and that also provides the ability to win the fight should deterrence fail. It is no easy matter to design a force structure that optimally serves both objectives. Strong defensive capabilities might exert a powerful deterrent effect, and so might weak ones; similarly, weak or strong defenses might create little deterrence. But emphasizing the deterrent purpose can produce a force with less warfighting capability, which in some settings could in turn undercut deterrence.

These considerations might little consequence if tomorrow’s world could safely be assumed to replicate yesterday’s. But it seems sure to be quite different, involving difficult challenges from adversaries armed with at least a few nuclear weapons-adversaries that might be regional powers, global contenders, or non-state terrorists. Kehler’s warning remains true today: “Operations against a regional adversary either having or presumed to have nuclear weapons would present problems that have never been directly faced and are not yet fully understood”(Naval War College Review, 1996). Absent a Cold War competition in which core national values were at stake, the credibility of American threats might not be so immediately evident to all. There might then be situations in which American credibility would require clear demonstrations of capability; perhaps events might even compel U.S. leaders to consider using one or two nuclear weapons.

Preparing for a future of that sort entails rethinking core elements of the strategic planning paradigm developed fifty years ago. As the House Armed Service Committee recently noted (Defense Authorization Report, May 2011), “the assumptions and scope of cold war-era nuclear analyses are vastly different than what is needed today.”

Will assured destruction continue to be the best available strategy to prevent nuclear attacks against the American homeland? Should it be reinforced and eventually replaced with defenses as they become increasingly effective? Should American nuclear forces be more versatile, flexible, and capable of engaging diverse targets around the world with precise and precisely limited effects? Should nuclear testing be resumed, with a view to developing such weapons? Should delivery systems include in-flight retargeting and termination? Is there a continuing need for land-based ICBMs? Will there be a need for some conventionally armed ICBMs? How might limited nuclear operations be integrated with forces for the joint fight? Is there a role for allies in these matters, and how might alliances be structured to deal with them?

Rethinking these questions and the many others that will then arise poses a vital challenge to planning and to the political consensus that has sustained the American approach to strategic affairs for a half-century and more. The planned modernization of the strategic delivery systems provides an opportunity to do so, and the changing strategic environment demands that we take it. After all, it may not only be our hardware that is out of date.

Bob Butterworth is a consultant and expert on nuclear issues and intelligence, especially spy satellites and the policies governing them. The president of Aries Analytics, Butterworth was former senior advisor to the head of Space Command and was a staffer on the President’s Foreign Intelligence Advisory Board, as well as on the Senate Select Committee on Intelligence.