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APPENDIX D
The Remaining Unique Role of Nuclear Weapons in Post-Cold War Deterrence

Wolfgang K.H. Panofsky, Stanford Linear Accelerator Center (Emeritus)

BACKGROUND

In the post-Cold War era, the United States has a strong reason to define the deterrent role of nuclear weapons to be as separate as possible from other means of deterring armed conflict. Several factors support such a widened gap. The first is that the United States is now the world's preeminent military power measured by prowess in conventional armament, and therefore the United States should be able to cope with foreseeable large-scale conflicts with conventional forces. There are, of course, smaller hostilities, such as those now unleashed as the result of loss of control over ethnic or other internal tensions which are beyond the reach of U.S. conventional forces, but nuclear intervention is surely not a solution. The second is that the principal nuclear threat to U.S. security now derives from proliferation of nuclear weapons rather than conflict among the five declared nuclear weapons states. There is at this time no plausible scenario projecting nuclear conflicts among the five, with a possible exception of a reemergence of a highly nationalistic aggressive regime in Russia. That latter threat, be it plausible or implausible, will take considerable time to evolve considering the derelict state of Russian military forces.

Proliferation of nuclear weapons is another matter. The United States has the greatest possible interest in stemming nuclear proliferation; nuclear weapons in some sense are the "great equalizer" among powerful and nonpowerful nations as firearms can be the equalizer between physically strong and weak individuals. Nuclear nonproliferation is codified in the Non-Proliferation Treaty (NPT), which came into force in 1970 for an initial 25-year period. This treaty is subject to periodic review, and a successful extension conference was concluded in the spring of 1995. With both Russia and the United States, and most of the Western allies, strongly favoring extension for an indefinite period, the conference extended the NPT without limit of time. Although this result is gratifying, it was not reached without controversy stemming from the inherent tensions the nuclear nonproliferation regime implies.

The NPT codifies an uneasy bargain among the nonnuclear weapons states party to the treaty and the five nuclear weapons states. The components of this bargain interpreted broadly are the following:

• The five declared nuclear weapons states are obligated not to transfer nuclear explosives and information concerning their design to



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Page 104 APPENDIX D The Remaining Unique Role of Nuclear Weapons in Post-Cold War Deterrence Wolfgang K.H. Panofsky, Stanford Linear Accelerator Center (Emeritus) BACKGROUND In the post-Cold War era, the United States has a strong reason to define the deterrent role of nuclear weapons to be as separate as possible from other means of deterring armed conflict. Several factors support such a widened gap. The first is that the United States is now the world's preeminent military power measured by prowess in conventional armament, and therefore the United States should be able to cope with foreseeable large-scale conflicts with conventional forces. There are, of course, smaller hostilities, such as those now unleashed as the result of loss of control over ethnic or other internal tensions which are beyond the reach of U.S. conventional forces, but nuclear intervention is surely not a solution. The second is that the principal nuclear threat to U.S. security now derives from proliferation of nuclear weapons rather than conflict among the five declared nuclear weapons states. There is at this time no plausible scenario projecting nuclear conflicts among the five, with a possible exception of a reemergence of a highly nationalistic aggressive regime in Russia. That latter threat, be it plausible or implausible, will take considerable time to evolve considering the derelict state of Russian military forces. Proliferation of nuclear weapons is another matter. The United States has the greatest possible interest in stemming nuclear proliferation; nuclear weapons in some sense are the "great equalizer" among powerful and nonpowerful nations as firearms can be the equalizer between physically strong and weak individuals. Nuclear nonproliferation is codified in the Non-Proliferation Treaty (NPT), which came into force in 1970 for an initial 25-year period. This treaty is subject to periodic review, and a successful extension conference was concluded in the spring of 1995. With both Russia and the United States, and most of the Western allies, strongly favoring extension for an indefinite period, the conference extended the NPT without limit of time. Although this result is gratifying, it was not reached without controversy stemming from the inherent tensions the nuclear nonproliferation regime implies. The NPT codifies an uneasy bargain among the nonnuclear weapons states party to the treaty and the five nuclear weapons states. The components of this bargain interpreted broadly are the following: • The five declared nuclear weapons states are obligated not to transfer nuclear explosives and information concerning their design to

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Page 105 nonnuclear weapons states, and nonnuclear weapons states agree not to produce or accept nuclear explosives. • Nuclear weapons states agree to make civilian applications of nuclear technology freely available to nonnuclear weapons states party to the NPT, provided such civilian activities are being carried out under "full scope" safeguards administered by the International Atomic Energy Agency. • By its nature this arrangement is discriminatory in freezing by treaty designated "haves" and "have-nots" in respect to nuclear weapons. To make this discriminatory regime acceptable to all NPT signatories, the nonproliferation bargain further provides (codified in Article VI of the NPT) that the nuclear weapons states shall diminish their nuclear arsenals and work toward their eventual elimination. Although this is not explicitly stated, the implication is that the nuclear weapons states should diminish the role of nuclear weapons as instruments of international policy to the maximum extent consistent with their national security. • The nuclear weapons states shall give both "negative" and "positive" security assurances to nonnuclear weapons states, meaning that they shall be committed not to use nuclear weapons against nonnuclear weapons states and shall give assurances to protect nonnuclear weapons states against threatened or actual nuclear attack by other states. • Whether this bargain will in fact hold or erode in time is one of the great challenges facing humanity. In the past it has never been possible to stem the diffusion of new military technologies once introduced. Technical barriers such as prohibitions on the transfer of critical materials and technology can only slow but not prevent proliferation. Although fissionable materials are essential to the construction of a nuclear weapon, most potential proliferators could produce the material indigenously given adequate resources. Nuclear weapons of very substantial, but less than optimum, capability can be constructed without access to information classified by the United States. Technical competence is growing throughout the lesser-developed world. Thus, ultimately, nuclear weapons proliferation can be prevented only if the nonnuclear weapons states are persuaded that their national security is served better without the possession of nuclear weapons than by their acquisition. Unless proliferation is to be countered by force or threat of force, the nuclear weapons states, including the United States, must view all elements of the nonproliferation bargain with utmost seriousness in revising their deterrence policies and therefore the roles which they expect nuclear weapons to play in the future.

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Page 106 The Nuclear Posture Review (NPR) completed late in 1994 is not a bottomup reexamination of these roles but only a pragmatic examination of the current situation and the near-term nuclear posture; the NPR is described as "interim" by the Department of Defense. While confirming the decreased role of nuclear weapons in U.S. security policy, the NPR essentially advocates a "reduce and hedge" policy: the reductions in nuclear weapons are essentially those already agreed to during previous administrations and the hedging provides for regrowth of U.S. nuclear forces by "re-MIRVing,'' that is, increasing the number of warheads of the U.S. strategic missile forces. The question of the basic future roles of nuclear weapons was not explicitly addressed; yet it is in this respect that the end of the Cold War implies the largest changes. THE HISTORY OF NUCLEAR DETERRENCE Historically, U.S. nuclear weapons served a variety of evolving purposes. The purpose of the first two nuclear weapons detonated over Japan was clear: they were to secure early termination of World War II. The controversy over whether Japan's surrender was imminent at any rate and whether the use of these weapons resulted in fewer combined Japanese and American casualties than if an invasion of Japan had been necessary will never be fully settled, nor will the question of the length of time by which the use of nuclear weapons actually did shorten World War II. We will also never know with certainty the extent, if any, to which the stockpiles of nuclear weapons with their rapid growth in the United States and Soviet Union during the Cold War deterred armed conflict. The historical evidence is clear that conventional weapons, including the potential availability of chemical or biological weapons, have not deterred all-out world wars; conversely, nuclear weapons also have not deterred the hundred or so localized nonnuclear conflicts which have taken a larger toll during the nuclear age than that inflicted by the nuclear weapons on Hiroshima and Nagasaki. Whether the ascendance of nuclear weapons has deterred, and thereby prevented, all-out large-scale war between the end of World War II and today will remain a subject of debate with happily no physical evidence to support either side. There is, however, no question that what has been called "existential deterrence" by nuclear weapons has been a major military factor since World War II. Although the Cold War consumed enormous resources and threatened a major holocaust, the superpowers actually conducted foreign policy and military operations with a great deal of caution. Direct contact between U.S. and Soviet forces was largely avoided, with essentially all actual military hostilities restricted to client states of the two powers. There were indeed tense moments, such as the Cuban missile crisis and the bombardment of Russian ships at Haiphong during the Vietnam War, but these crises were in effect settled by the preponderance of conventional power, with nuclear threat only as backdrop. The nuclear deterrent concepts during the Cold War evolved from "massive retaliation," which threatened the Soviet Union with nuclear reprisals in case of

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Page 107 unacceptable conduct, be it nuclear or nonnuclear, to the doctrine designated as "flexible response" and then "extended deterrence." In essence flexible response provided that the United States would use nuclear weapons first in case Soviet aggression in Europe would threaten defeat of NATO by conventional forces. Extended deterrence generated in effect a U.S. nuclear umbrella over its allies in case of Soviet aggression. The Bush administration proclaimed a doctrine of "weapons of last resort" for the use of nuclear weapons, restricting their use to situations where U.S. supreme national interests were threatened. Each of the above doctrines has always reflected, deliberately or not deliberately, a large degree of ambiguity. With the U.S. homeland vulnerable to nuclear retaliation by the Soviet Union, the question of when or whether a U.S president would actually order the use of nuclear force could never be projected in advance but would have to be resolved under the exigencies of the moment. The use of nuclear weapons was considered, but firmly rejected, during the Vietnam and Korean conflicts. Another internal contradiction reflected in the U.S. post-Cold War nuclear posture was the tension between secrecy and deterrence. The SIOP, that is, the operational plans among which the President could choose for the execution of nuclear strikes, remained very highly classified; such quantities as the total nuclear inventories, the yield and precision of U.S. nuclear weapons, and many other "things nuclear" were withheld from the public and thereby possibly from the Soviets. Yet the essence of deterrence is to threaten an opponent with a credibly unacceptable outcome, and the opponent could evaluate the reality of the threat only if he has knowledge of plans and deployments. This need for secrecy in the deterrent posture is also now under review and the Department of Energy's "Openness Initiative" is a move toward declassifying at least some of the total U.S. nuclear resources, even if operational plans beyond the general outline provided by the NPR remain secret. Of course much of the supposedly secret inventories have de facto been known to the public, and certainly to the Soviets, as is witnessed by many publications on the subject. The basic internal contradiction of any deterrent posture which projects non-use of nuclear weapons by threatening the use of nuclear weapons remains. The question of the credibility of the U.S. nuclear deterrent posture has remained a continuing subject of debate, and the evolution of the French and British independent nuclear deterrent forces bear witness to this dubious credibility. But all this is history with the end of the Cold War, with the United States emerging as the supreme military power in conventional arms, and with proliferation of nuclear weapons constituting a larger threat to U.S. security than the risk of a nuclear exchange among the nuclear powers. What residual mission for nuclear weapons can be justified? FUTURE NUCLEAR WEAPONS MISSION Although initially acquisition of nuclear weapons was generally justified by a "more bang for the buck" rationale, the core purpose of U.S. nuclear weapons

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Page 108 has always been to deter the threatened or actual use of nuclear weapons by foreign powers against the U.S. homeland, U.S. allies, or U.S. interests overseas. During the Cold War, this core purpose usually incorporated the term "mutual" in such descriptions as mutually assured destruction or mutual deterrence. Barring reignition of NATO tensions with Russia, with its still partially intact nuclear weapons, the deterrence aspect of U.S. policy has now lost its bilateral focus and "mutual" no longer applies. However, the core purpose, referring to deterrence of nuclear aggression from whatever quarter it might originate, remains a principal rationale for retention of nuclear weapons. There is continuing debate over whether, or how, the concept of nuclear deterrence can be, or should be, modified from its bilateral meaning during the Cold War to deterrence of potential proliferators presumably from the Third World, including the so-called "rogue" states. During the Cold War the quantitative size of the required nuclear forces on the part of the United States which might deter the Soviet Union was always debatable. But the basic concept that responsible leadership would refrain from hostilities if the very survival of their nation (or their own leadership), or their ability to continue armed conflict, was threatened has rarely been doubted. Yet during the Cold War, the number of U.S. nuclear armaments became vastly in excess to satisfy the requirement that the Soviet Union could not continue hostilities after U.S. retaliation by its forces surviving a conjectured Soviet first strike. It should be noted that delivery of about 100 nuclear weapons could reduce the electricity supply in the Soviet Union by over a factor of two and that the impact of 150 nuclear weapons could reduce industrial capacity by a similar factor. Again a few hundred weapons would reduce deployed general-purpose forces of the Soviet Union and command and control centers by a large factor. Today such figures are overestimates for required deterrent forces against a possible reemergence of a Russian nuclear threat: Russia contains only parts of the former economic assets of the former Soviet Union and its military basing structure. Thus the core purpose against the reemergence of an aggressive Russia requires forces only a small fraction of those contemplated for START II. Under the core deterrent role of nuclear weapons, the "hedge" provided by the NPR is unnecessary and large reductions below START II levels are feasible. The question continues to surface whether the assumed rational leadership of the then Soviet Union, and presumed to exist currently in Russia, has now been superseded by the potential of irrational leadership on the part of Third World countries or possibly new leadership of Russia. Since any theory of deterrence requires some degree of rational leadership of the to-be-deterred party, claims continue that we are now facing "undeterrable" states. I consider such arguments to be unproductive and to some extent insulting to the leaders of the Third World. I find it impossible to distinguish the rationality of a Stalin, Hitler, Khadaffi, Saddam Hussein, or Kim Song-II in this respect. No deterrence strategy can ever fully assure coercion of an opponent into inaction. The risk of irrational response, or the evolution of circumstances

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Page 109 which even rational leadership cannot control, can never be fully ruled out. Yet today, although certain leaders might be ruthless and may miscalculate, the "rogue" status of certain nations does not in any way imply that they are suicidal. Although the possibility of suicidal fanatic leadership cannot be totally discounted, the history of the Gulf War and subsequent confrontations has demonstrated that leaders of "rogue" nations do back down when appropriately confronted. The threat of nuclear terrorism by subnational groups, with or without acknowledged encouragement by the leadership of "rogue" nations, is another matter. A nuclear response against such threats may not be feasible—the home base of the potential attacker may not be known. The threat of nuclear weapons in the hands of suicidal fanatics, such as the Japanese cultists who recently released poisonous nerve gas in the Tokyo subway, can clearly not be credibly countered by deterrence in any form. Only worldwide vigilance and an unrelenting effort to prevent the possession of nuclear weapons by such groups can limit this risk. Thus although indeed the "core" deterrent role of nuclear weapons (or any other strategy) will not prevent delivery of nuclear weapons under all conceivable circumstances, deterring nuclear aggression remains the least risky military course in preventing such a catastrophe. Defenses of sufficient impenetrability to prevent the delivery by any means of a sufficient number of nuclear weapons to inflict horrendous damage are demonstrably impossible. The risk inherent in any potential catastrophe is the product of the probability of occurrence of such a catastrophic event times the consequence of such an event. The probability of nuclear weapons delivery can never be reduced to totally zero as long as nuclear weapons remain, but the core deterrent function of U.S. nuclear weapons remains the principal means to minimize this probability in today's world. The consequence of potential delivery can be reduced from what used to be potential annihilation of civilization to what even now would be an unprecedented catastrophe but one of finite dimensions. Therefore risk minimization demands both retention of the core deterrent purpose of nuclear weapons combined with the maximum feasible reduction of stockpiles consistent with that purpose and an increased emphasis on the safety and reliability of command and control. For the above reasons the core purpose of nuclear weapons, that is, deterrence of nuclear threats or actual use of nuclear weapons, has retained its value in thepost-Cold War era. The question remains whether this is the only purpose which should form the basis of the U.S. nuclear posture in the future. Justification for the flexible response doctrine, which became NATO policy under the Cold War, has now lost its validity, since defeat of conventional U.S. and NATO forces by a superior opponent in Europe is no longer a possibility. Yet this NATO policy has never been formally withdrawn. It is worth noting that during the Cold War the U.S. flexible response posture was met by the Soviet Union's proclamation of a "no first use" policy knowing full well that NATO would not accept this. Now with Russia's conventional forces

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Page 110 drastically reduced in number and of dubious morale and readiness, Russia has turned around and proclaimed for itself the former NATO doctrine of flexible response, that is, an implied willingness to use nuclear weapons in response to threatened conventional defeat. Clearly U.S. interests would be served best by diplomatically opposing this reversal and by monitoring the pattern of Russian deployments, rather than by the United States retaining a no longer needed flexible response posture. Continuing to describe the function of nuclear weapons as weapons of last resort, as was introduced during the Bush administration, has superficial attractiveness but could have serious negative consequences in view of the overriding interest of the United States in the nonproliferation of nuclear weapons. There is no plausible or foreseeable nonnuclear threat faced by the United States either in respect to its homeland or abroad which could threaten U.S. supreme national interests and which could not be countered by conventional means. In contrast many states of the world face severe threats to their very existence. The "weapons of last resort" doctrine, when applied to such states, constitutes a valid excuse for such states to acquire nuclear weapons; indeed the justification for the nuclear weapons potential of Israel and Pakistan is just that. In fact, under such a doctrine, possession of nuclear weapons is much easier to justify for such states than it is for the United States. In other words, the weapons of last resort doctrine can provide justification for universal nuclear proliferation; therefore this U.S. doctrine, which was not formally revoked after the end of the Cold War, should be abandoned. The deterrent value of nuclear weapons against threatened or actual use of chemical and biological weapons continues to surface. Such weapons, together with nuclear weapons, are frequently classified as weapons of mass destruction (WMD). I consider aggregation of nuclear, chemical, and biological weapons into a single WMD category to be counterproductive. Chemical weapons are by no means weapons of mass destruction. In fact the military effectiveness of chemical weapons for a given weight of delivered munitions may be less against prepared enemy troops than that of conventional explosives. They remain principally weapons of terror meant to intimidate civilian populations. In contrast nuclear weapons can increase the destructive energy delivered by a given weight of munitions by well above a factor of 1 million relative to conventional explosives. In principle biological weapons may produce lethal results comparable to nuclear weapons per unit weight of delivered munitions against civilian populations, but happily the military effectiveness of biological weapons remains to be established. Biological weapons are not effective battlefield weapons. Biological weapons have not been used in modern times except in a limited way by the Japanese in the Manchurian conflict. Whatever the eventual lethality of biological weapons may turn out to be, biological weapons are not expected to be decisive or even major tools in warfare in the foreseeable future. Therefore biological and chemical weapons should not be classified in a single WMD category with nuclear weapons; their evolution should be countered by

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Page 111 military nonnuclear means and pursuit of treaties and conventions specifically dedicated to that purpose. Threatening the use of nuclear weapons to deter such weapons is doubly counterproductive. By proclaiming that nuclear weapons may be necessary to counter biological or chemical warfare, the United States may inadvertently actually accelerate the development of these means of warfare by de facto characterizing them as the "poor man's nuclear weapon." Moreover, extending the potential use of nuclear weapons to deter chemical and biological weapons runs counter to the obligation assumed by the United States under the nonproliferation bargain to shrink rather than expand the military and political leverage of nuclear weapons. This obligation is in fact recognized in the NPR, which emphasizes that the purpose of the DOD counterproliferation initiative is to give military commanders, and the President, a sufficient range of nonnuclear options to contain the biological and chemical weapons threats. Similar arguments apply to future uses of nuclear weapons in foreseeable military situations where such use might be more cost-effective than conventional means of military action. For instance deeply buried command and control centers might be easier to dig out, enemy massed armor might be more effectively attacked, and other specialized military objectives might be easier to obtain. Yet to the extent that such military missions can be accomplished at all, they can be executed with conventional means. The bargain documented by the NPT obligates the United States to deemphasize rather than to expand the role of nuclear weapons. This obligation should take precedence over cost-effectiveness for highly limited and specialized conjectured situations. CONCLUSIONS • The core purpose requires a considerably smaller number of strategic nuclear weapons than those implied by START II, and therefore a clear understanding of this sole role should make possible a more aggressive U.S. position in seeking reductions in START III. The naval ballistic missile nuclear submarine force is apt to remain the backbone of that role for the foreseeable future. The core role does not require a significant number of tactical nuclear weapons. Thus the total number of U.S. nuclear warheads, now foreseen to be nearly 10,000 for the beginning of the next century once START II has been implemented, could be drastically reduced. Tactical nuclear weapons could be totally eliminated.

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Page 112 • Restricting the role of U.S. nuclear forces to the core role would make the threat of U.S. nuclear retaliation against nuclear aggression by others more credible by not diluting the mission with other, less credible, deterrent roles. Thus under such a clear policy, U.S. forces would exert larger leverage against nuclear proliferation by making it clear that such proliferation would result in intolerable risks to the proliferant. • Restriction of U.S. nuclear weapons to the core function would go a long way to satisfy U.S. critics that the obligations under Article VI of the NPT are being met by decreasing the use of nuclear weapons as tools of international diplomacy and by permitting much more drastic reductions of nuclear forces than those inherent in present commitments. It could be viewed to meet obligations of Article VI as a step toward eventual elimination of nuclear weapons in a future era where possession of such weapons by other powers is no longer plausible. If the core function remains the only justifiable role of U.S. nuclear weapons, the question continues to resurface whether this fact should be recognized by declaratory policy or merely be implemented by such actions as reduced numbers of nuclear weapons, elimination of tactical nuclear forces, reduced quick response readiness, improved survivability, and more robust command and control. Restricting the nuclear role to respond to nuclear threats only is de facto equivalent to a "no first use" policy which used to be advocated by the then Soviet Union, but has been withdrawn recently by Russia but is still proclaimed by China. A declaratory no first use policy has been so much used and abused in past propaganda by various nations that a similar proclamation by the United States would lack credibility. Moreover such a restriction could not be binding in case of war at any rate and therefore has limited operational significance in itself. Therefore a pragmatic shift in nuclear weapons deployments corresponding to the core function only is superior to a proclaimed policy. The summary conclusion of these considerations is that the role of nuclear weapons to deter the use or threat of use of nuclear attack by other nations continues to have at least as much validity today as it had during the Cold War but that it should be their only mission. Although no strategy can assure that nuclear weapons will never by used again, such a highly limited role offers the maximum leverage toward avoidance of nuclear conflict and toward a worldwide decrease in nuclear weapons inventories. Deterrence of nonnuclear conflict should be separated as much as possible from the goal of deterrence of nuclear war.