Nuclear Weapons and International Law: Existential Risks of Nuclear War and Deterrence through a Legal Lens

By Charles J. Moxley, William J. Perry, John D. Feerick and Claire Finkelstein

This two-volume book provides a comprehensive analysis of the lawfulness of the use of nuclear weapons, based on existing international law, established facts as to nuclear weapons and their effects, and nuclear weapons policies and plans of the United States. Based on detailed analysis of the facts and law, Professor Moxley shows that the United States’ arguments that uses of nuclear weapons, including low-yield nuclear weapons, could be lawful do not withstand analysis.

Moxley opens by examining established rules of international law governing the use of nuclear weapons, first analyzing this body of law based on the United States’ own statements of the matter and then extending the analysis to include requirements of international law that the United States overlooks in its assessment of the lawfulness of potential nuclear weapons uses. He then develops in detail the known facts as to nuclear weapons and their consequences and U.S. policies and plans concerning such matters. He describes the risks of deterrence and the existential nature of the effects of nuclear war on human life and civilization.

He proceeds to pull it all together, applying the law to the facts and demonstrating that known nuclear weapons effects cannot comply with such legal requirements as those of distinction, proportionality, necessity, precaution, the corollary requirement of controllability, and the law of reprisal. Moxley shows that, when the United States goes to apply international law to potential nuclear weapons uses, it distorts the law as it has itself articulated it, overlooks law in such areas as causation, risk analysis, mens rea, and per se rules, and disregards known risks as to nuclear weapons effects, including radioactive fallout, nuclear winter, electromagnetic pulses, and potential escalation. He then shows that the policy of deterrence is unlawful because the use of such weapons would be unlawful.

Moxley urges that the United States and other nuclear weapons States take heed of the requirements of international law as to nuclear weapons threat and use. He argues that law can be a positive force in society’s addressing existential risks posed by nuclear weapons and the policy of nuclear deterrence.

• Language: English
• Publisher: RowmanLittlefield
• Release date: May 15, 2024
• ISBN: 9780761873556

Book preview

Introduction

U.S. POSITION

The U.S. position is that there is no conventional or customary rule of law specifically prohibiting the use of nuclear weapons and hence that the use of such weapons is presumptively lawful. The United States recognizes, however, that the law of armed conflict, including the rules of distinction, proportionality, and necessity, and their corollary, the requirement of controllability, apply to the use of any weapon, including any nuclear weapon. The United States acknowledges that the use of a nuclear weapon would be unlawful if, in the circumstances, it would violate any of these rules. The legality of their use must, the U.S. asserts, be determined on a case-by-case.

In taking this position, the United States recognizes that, under the applicable rules, the lawfulness of the use of nuclear weapons turns largely on the potential effects of such use. The U.S. defense before the International Court of Justice (ICJ) of the lawfulness of use of nuclear weapons was premised in major part on the United States’ asserted ability to use certain nuclear weapons (ostensibly, precision low-yield ones) in such a way in certain circumstances as to limit and control their effects,

The United States recognizes that the use of nuclear weapons would be unlawful under the rules of distinction, proportionality, and necessity, if the effects of the use would not be controllable and actually controlled during the nuclear strike.

The United States further recognizes that a nuclear strike would be unlawful under the rule of distinction if its effects could not discriminate military from nonmilitary targets.

The United States similarly recognizes that a nuclear strike would be unlawful under the rule of proportionality if its effects on protected persons and objects would be disproportionate to the concrete and direct military benefits of the strike.

Likewise, the United States recognizes that a nuclear strike would be unlawful under the rule of necessity, if it was not actually necessary to use nuclear weapons to achieve the particular objective, i.e., if conventional weapons would suffice.

The United States’ defense of the lawfulness of nuclear weapons before the ICJ was thus specifically based on its contention that it is able to deliver such weapons (ostensibly, a small number of precision, low-yield devices) accurately against discrete military targets in remote areas, and of doing so in such a way as to control and limit resultant nuclear radiation and other effects and not kill or injure substantial numbers of noncombatants. The United States further told the Court that the potential effects of using nuclear weapons are not materially different from those that would be caused by modern conventional weapons and disputed that the limited use of low-yield nuclear weapons would necessarily escalate into a strategic nuclear exchange.

THE EXISTENCE OF BINDING LEGAL RULES

The striking point is that, notwithstanding the obvious political and national security issues that are present, there is law in this area, and the United States recognizes such law,¹ and indeed, as we shall see, asserts that it has integrated such law into its military training and planning. Perhaps even more striking is that the proponents and opponents alike of the nuclear weapons regime largely agree on the substance of such governing rules of law.

THE ICJ’S NUCLEAR WEAPONS ADVISORY DECISION

The ICJ, in its 1996 advisory decision as to nuclear weapons, largely mirrored the United States’ non-defense of the lawfulness of the use of large-scale nuclear weapons, but declared itself unable to decide whether a more limited use of such weapons could ever be lawful.

Specifically, the Court determined that, because of the potential of nuclear weapons to destroy human life and civilization and the entire ecosystem of the planet, the use of nuclear weapons would generally be unlawful, but that it did not have sufficient law or facts before it to determine whether use of nuclear weapons (ostensibly precision, low-yield tactical ones, although the decision was somewhat ambiguous in this regard) would potentially be lawful in extreme circumstances of self-defense when a state’s very survival is at stake.

The Court further stated that it did not have sufficient facts before it to determine the validity of the argument of the United States and other nuclear weapons states that low-yield nuclear weapons could be used in such a way as to limit and control their effects sufficiently to make the uses lawful.

APPROACH

The U.S. position and the ICJ decision constitute the starting point of my analysis: The Court may not have had the facts before it, or even fully acknowledged the scope of the potentially relevant facts available to it, but the facts exist, and are generally unclassified and openly available. We need to identify them, put them on the table, and examine them in the light of the applicable law.

My analysis proceeds on two levels. First, I review the applicable law, as articulated by the United States, and apply it to widely recognized and ostensibly incontrovertible facts as to nuclear weapons and their effects. Secondly, I review certain additional rules and principles of international law that the United States largely seems to overlook or not generally apply in its analysis of the lawfulness of nuclear weapons threat and use.

The U.S. position and the ICJ decision are covered in Part I (Chapters 1–3); additional principles of law are covered in Parts II and III (Chapters 4–13); and the facts are covered in Part IV (Chapters 14–26). My conclusions are set forth in Part V (Chapters 27–28).

Under this approach, I largely base the analysis on the United States’ own statements of the applicable law and upon statements of the facts so widely recognized as to be essentially incontrovertible.

The law of armed conflict is communicated by the U.S. military through military manuals setting forth such law for training and planning purposes and for potential discipline of personnel for violations. In Chapter 1, I review the rules of the law of armed conflict, as such rules are articulated in U.S. military manuals and other U.S. sources.

In Chapter 2, I review statements from the military manuals and arguments of the United States before the ICJ setting forth the United States’ position as to the application of such rules of law to the threat and use of nuclear weapons. Here, we see substantial back-tracking by the United States from its general statements of the applicable rules, as described in Chapter 1, when it comes to applying them.

APPLICABLE FACTUAL AND LEGAL QUESTIONS

The U.S. focus, in its defense of nuclear weapons before the ICJ, on the asserted lawfulness of the purportedly possible surgical use of one or a small number of precision low-yield nuclear weapons against remote military targets staked out not only a factual position as to the characteristics and effects of certain nuclear weapons and their delivery systems, but also an implicit legal position as to the scope of the facts relevant to the analysis.

Specifically, the U.S. position implies that, in evaluating the lawfulness of the limited use of low-yield tactical nuclear weapons, one should look at the matter in the abstract, in a hypothetical test tube type fashion, without reference to risk factors that will inevitably be present with even the most limited of nuclear weapons uses, including such risks as those of hitting the wrong target or of precipitating a nuclear, chemical or biological weapons response and possible escalation to more widespread uses of such weapons, or of causing nuclear winter or the failure of electronic devices across huge areas of the world.

The extent of such risk factors is only heightened by the fact that the circumstances in which the United States might actually consider using nuclear weapons would by definition be ones of extreme military challenge and hence of volatility, with considerable pressures of all kinds upon people and equipment.

NEED FOR EVALUATION BASED ON PROBABILITIES

If it were possible to wait and see what happens, with at least the theoretical prospect of a war crimes prosecution if the strike turned out to exceed legal limits, the integrity of the rule of law in this regard might be preserved. But with nuclear weapons, of course, there may be no such luxury of hindsight; the stakes are too high. If the law is to be applied at all, it must be in advance, when only estimates of probabilities can be known (Chapters 1–2, 14, 27 and 28). That limitation is inescapable, yet our thinking, as reflected in the U.S. treatment of the matter before the ICJ (Chapters 2, 3), has yet to come to grips with this aspect of the matter.

The issues as to the scope of the relevant facts and the appropriate treatment of probabilities were not focused on by the United States in its arguments to the ICJ or addressed in any depth by the ICJ in its advisory opinion, and appear not to have been much focused on at all in the literature on this subject (Chapters 2, 3, 27 and 28). Yet they seem to be the heart of the matter.

Nor are they beyond the ability of legal systems to address. The imposition of civil and criminal liability based upon unjustifiable risk creation is a central function of law throughout the world and international law addresses and is able to deal with such matters.

The applicable rules of law, as described by the United States (Chapters 1 and 2) and as analyzed by the ICJ in its decision (Chapter 3), provide guidance as to the scope of relevant facts, and, hence, as to the consideration that must be given to probabilities in conducting the legal analysis. The rules of distinction, proportionality, and necessity, and even those of civilian immunity and neutrality, are rules of reason, as is the overriding rule of precaution (Chapter 1) that require states to exercise reasonable care that the military and civilian persons through whom they act comply with the law of armed conflict. Compliance of states with the law of armed conflict is, in every circumstance, to be evaluated in light of all of the reasonably available facts, including particularly those bearing on the likely effects of the use of nuclear and other weapons.

RANGE OF FACTUAL ISSUES

This brings into the analysis a wide range of facts, including as to such matters as the following:

The characteristics, capabilities, and effects of nuclear weapons and their delivery systems, including of low-yield nuclear weapons (Chapter 14);

U.S. declaratory and operational policies as to the circumstances in which the United States might actually consider using nuclear weapons and the United States’ assumptions as to how other states might act in response to such a uses (Chapters 15-16);

the U.S. nuclear force structure, consisting of the nuclear weapons available for use and whose potential use is the subject of U.S. military training and contingency planning (Chapter 17);

actual experience as to the times the United States has threatened or considered the use of nuclear weapons, reflecting the risks of U.S. nuclear policy and planning and of the international nuclear weapons regime that the United States has permitted to remain in place without seriously trying to change it (Chapter 18);

probabilities of as to the accuracy with which the United States could likely deliver nuclear weapons to designated targets (Chapter 19);

risks inherent in the policy of nuclear deterrence, including risks of inadvertent uses of nuclear weapons, whether because of human or equipment error, including risks of cyber intrusion into command and control (Chapter 20);

risks of repetition of the many documented instances of near misses, when nuclear weapons states, including the United States and the Soviet Union/Russia, came close to using nuclear weapons based upon faulty information or misperceptions as to the actions and intentions of the other side and other human and equipment failures (Chapter 21);

the nuclear arsenals of other states, reflecting the scope of volatility as to weapons that might be brought into play in the event of major international confrontations (Chapter 21);

the risks of a nuclear response and potential escalation that a nuclear strike might precipitate (Chapters 22–24);

risks that even a limited use of nuclear weapons would precipitate use of chemical or biological weapons and vice versa (Chapter 25); and

risks associated with the failure of our nuclear planning and policy of nuclear deterrence to keep track of the extent to which today’s high tech conventional weapons are able to accomplish military objectives for which nuclear weapons might previously have been considered (Chapter 26).

POTENTIAL PER SE UNLAWFULNESS

The question is whether substantial risks, including existential risks, are so inherent in the threat and use of nuclear weapons, in the types of circumstances in which such weapons might be used, and so serious, as to render even the most limited uses of nuclear weapons unlawful. This is the central theme of the fact chapters (Chapters 14–26) and I attempt to pull it all together in Chapters 27 and 28.

APPLICATION OF ESTABLISHED PRINCIPLES OF LAW

The United States argued to the ICJ that there can be no per se rule prohibiting the use of nuclear weapons unless the United States has specifically agreed to such a rule. This raised legal issues as to the nature and sources of international law and particularly as to the role of general rules of customary international law, such as the rules of distinction, proportionality, and necessity: Are such rules binding no matter how they cut, or is their application subject to the consent of the individual state against which they are being applied? I address this issue in Chapters 1, 27 and 28.

REQUISITE MENTAL STATE FOR WAR CRIMES LIABILITY

One way of approaching the question of potential culpability for risk creation in the nuclear weapons area is to consider the requisite mental state for war crimes liability. Is it required, for example, as the United States has at times contended, that, to be unlawful, a particular use of nuclear weapons would have to necessarily or inevitably involve the deliberate causing of impermissible effects, or are recklessness, wantonness, gross negligence or, in some instances, even negligence sufficient? I address the U.S. position on the issue in Chapters 1 and 2, and analyze the issue more broadly in Chapters 6–8, and 28.

INTERPRETATION OF LAW IN LIGHT OF ITS PURPOSE

As addressed in Chapter 5, it is a fundamental principle of construction that, at least in cases of doubt, treaties and rules of international law, like rules of law generally and, indeed, parties’ contracts, are to be interpreted and applied in light of their purposes. In Chapter 1, I address U.S. statements as to the purposes of the law of armed conflict. In Chapter 28 I examine the implications of such purposes in applying the law of armed conflict to nuclear weapons threat and use.

ANALYSIS BASED ON RULES AND PRINCIPLES OF INTERNATIONAL LAW SEEMINGLY NOT CONSIDERED BY THE UNITED STATES IN THE NUCLEAR WEAPONS CONTEXT

While my first approach is primarily based on U.S. statements of the applicable law, this second approach, addressed primarily in Chapter 28, brings to the fore rules of international law that do not appear to be regularly or consistently applied by the United States in analyzing the lawfulness of nuclear weapons threat and use.

Such areas include the international law of risk creation and causation and the need, in conducting the legal analysis, to consider all of the foreseeable effects of nuclear weapons, including radioactive fallout, and potential electromagnetic pulse (EMP) and nuclear winter effects, and potential nuclear responses and escalation by targets of nuclear weapons strikes (Chapter 28).

PREREQUISITES FOR A PER SE RULE

For a per se rule to arise, is it necessary that every single imaginable use be unlawful? Or is it sufficient if most such uses would be unlawful? Or if uses of such weapons, in the types of circumstances in which they would likely, if ever, be used, would be unlawful? I address such issues in Chapters 1, 2, 4 and 28.

WEIGHING OF PROBABILITIES

If my analysis is correct, a major issue becomes the following: What level of risk of impermissible effects makes a potential nuclear weapons strike unlawful? How are risks of nuclear weapons effects to be weighted and evaluated, including small risks of extremely severe, even apocalyptic effects?

Such matters can be conceptualized as presenting issues as to limits on permissible risk creation and as mens rea issues as to the mental state necessary for war crimes liability. I address such matters in Chapters 6–8, analyzing various approaches for evaluating permissible risk creation and addressing necessary mens rea states. I present my overall analysis as to such matters in Chapter 28.

THE SO WHAT QUESTION

What difference would unlawfulness make, since the weapons cannot be uninvented? This is the inevitable question—the one I am most asked by all types of audiences, as I have spoken on this issue over the years. This concern must be addressed if the matters discussed in this book are to have any practical significance.

EFFECTS OF THE U.S. POSITION OF PRESUMPTIVE LAWFULNESS

The United States’ position of presumptive lawfulness has significant effects. It means that U.S. strategic training and planning proceed on the presumption that nuclear weapons can be used (Chapters 2, 15–16). Nuclear weapons, the thinking goes—as expressed in the United States’ public statements—are a working part of the national arsenal, and the military are charged with being prepared to use them and in fact maintain detailed contingency plans to do so from a mindset of presumptive lawfulness (Chapters 2, 15–17, 24, 26).

In the extreme circumstances in which the President or the military might turn to these weapons, there would likely be little inclination or opportunity to focus on the intricacies of international law, particularly given the U.S. position that the lawfulness of any potential use of nuclear weapons by the United States would have to be decided on an ad hoc basis in light of the circumstances of the particular contemplated use. Advance planning might have covered some of the ground, but a decision would need be made, probably quickly (as we shall see, likely within minutes) and not very clearheadedly, in circumstances of extreme stress, adrenalin, and, it must be assumed, deep feelings of grievance, anger, danger and urge towards retribution on the part of decision-makers, amounting, likely, to a reality whereby the impetus would be compelling to just use the weapons and get it over with (Chapters 2, 23–24).

The upshot is a substantial likelihood that a possible use by the U.S. of nuclear weapons in exigent circumstances would not be subjected to serious consideration or even awareness as to consequences or legalities. The conclusion is compelling that the United States’ position of presumptive lawfulness is functionally equivalent to one of a green light for use, making the entire enterprise susceptible to individualistic, potentially idiosyncratic and impulsive decision-making. Because of the likely time limitations and emotional factors, presumptive lawfulness becomes per se lawfulness as far as the constraints of the law are concerned (Chapters 2, 28).

This reality has serious implications, particularly given the extent to which public awareness of the potential repercussions of nuclear weapons use has receded. Some U.S. political and military leaders might contemplate the actual use of these weapons in extreme circumstances, notwithstanding the widescale recognition by the U.S. leadership during and after the Cold War that nuclear weapons are so dangerous and destructive as to make such weapons (Chapters 22–23), as Kosta Tsipis expressed it in his Foreword to the first edition, not even weapons.

As a result, presumptive lawfulness serves to validate the United States’ policy of nuclear deterrence, whereby the U.S. threatens the potential use of nuclear weapons in circumstances as broad and nebulous as to address challenges that the United States deems to be adverse to its vital interests.

SIGNIFICANCE OF PRESUMPTIVE LAWFULNESS TO DETERRENCE

Because of the United States’ policy of the presumptive lawfulness of the use of nuclear weapons, the U.S. decision as to whether to use nuclear weapons in exigent circumstances will likely be a product not of what the civilian or military decision-makers independently decide is appropriate in the circumstances, but rather of years of the U.S.’s training and conditioning of its armed forces and civilian leaders, years of formulating and internalizing strategic doctrines fostering potential use of such weapons and developing contingency plans, target lists and approaches and the like for use of such weapons in the event of the failure of deterrence (Chapters 14–17, 24).

The United States acknowledged as much before the ICJ, in arguing that the cred ibility of nuclear deterrence depends upon the legality of the use of such weapons. If the use of nuclear weapons were determined to be unlawful, the United States would be required to revise its equipment procurement, force structures, planning, and training. One of the lead U.S. lawyers argued to the ICJ:

[E]ach of the Permanent Members of the Security Council has made an immense commitment of human and material resources to acquire and maintain stocks of nuclear weapons and their delivery systems, and many other States have decided to rely for their security on these nuclear capabilities. If these weapons could not lawfully be used in individual or collective self-defense under any circumstances, there would be no credible threat of such use in response to aggression and deterrent policies would be futile and meaningless. In this sense, it is impossible to separate the policy of deterrence from the legality of the use of the means of deterrence. Accordingly, any affirmation of a general prohibition on the use of nuclear weapons would be directly contrary to one of the fundamental premises of the national security policy of each of these many States.

The United States further stated in its memorandum to the ICJ:

It is well known that the Permanent Members of the Security Council possess nuclear weapons and have developed and deployed systems for their use in armed conflict. These States would not have borne the expense and effort of acquiring and maintaining these weapons and delivery systems if they believed that the use of nuclear weapons was generally prohibited.

PERSPECTIVE OF THE UNITED STATES

I have written this book largely from the perspective of the United States to highlight the extent to which the unlawfulness of the threat and use of nuclear weapons is evident from statements of the applicable law by the United States and essentially incontrovertible facts. Yet the U.S. statements of the law are not gratuitous. As made clear in the ICJ’s Nuclear Weapons Advisory Opinion, they broadly describe rules of law equally binding on other states.

THE UNCERTAIN CONTINUATION OF THE LUCK OF THE PAST

The stakes are high. On one level, deterrence, in the view of some, worked during the Cold War and indeed the huge financial costs of the nuclear weapons regime, augmented by President Reagan’s Star Wars bluff, may have worked, substantially contributing to the demise of the Soviet Union, although some dispute the matter.

However one comes out on the question of whether deterrence worked, we were lucky during the Cold War, as Robert McNamara pointed out in his Foreword to the first edition of this book. Nuclear weapons had just been invented, and this was the first test of our civilization’s ability to handle them. Risks were taken that threatened everything. But such luck cannot be counted on; human experience is to the contrary.

NOTE TO READER

Text and Footnotes

There are several ways to approach this book. The text addresses the matters covered at somewhat of a broad level. A deeper level of detail and authority is provided in the footnotes.

Internet Links

For ease of reference, I have included internet links to many of the sources cited. However, we have found that these links frequently change, sometimes even as one is looking at them, although usually a follow-up search will be fruitful. As to the U.S. military manuals, which I discuss at length throughout the book, later editions are constantly appearing, in some instances on an annual basis, although the substance remains fairly constant. Indeed, that is part of the point––how deeply and broadly entrenched the nuclear weapons regime has become, to the point that it takes an act of will to look at it freshly and realize its implications.

STEPS FORWARD

We now embark on a review of the applicable law and facts to enable us to assess the lawfulness of nuclear weapons threat and use.

Footnote

1. As we shall see, there are additional area of international law that are more in contention or not recognized as applicable to nuclear weapons threat and use.

I

THE LAW

Part I is made up of three chapters that address applicable law. Chapter 1 addresses the overriding principles and rules of the law of armed conflict applicable to the use of force, including the use of nuclear weapons, as articulated by the United States. Chapter 2 looks at how the United States applies this body of law to the threat and use of nuclear weapons. Chapter 3 takes the analysis to the next step, broadening the analysis beyond the perspective of the United States. It addresses how the International Court of Justice (ICJ) analyzed these issues in its 1996 Nuclear Weapons Advisory Decision.

1

The Law as Seen by the United States

I start, somewhat atypically, with an analysis of the law. Here’s why. We all have a general sense about nuclear weapons: They cause huge explosions and release lethal radiation that can spread widely in space and time. Nuclear war would be a disaster for all who came within its effects, but, in the meantime, nuclear deterrence—the threat of the use of these weapons to prevent others from attacking us—by some accounts prevented a hot war between the United States and the Soviet Union during the Cold War, and may continue to have such an effect. Nuclear weapons cannot be uninvented and hence are here to stay, as the cliché goes.

At first blush, this would seem to be substantially all we need to know. If my analysis is correct, however, the situation is substantially more nuanced: The legal analysis hinges on very specific and detailed facts and projected facts as to the effects and risks of nuclear weapons and related policies and practices of nuclear weapons states. Like a litigator handling a case, to perform this analysis we must become experts in the factual areas at hand. Because the indispensability of the detailed probing of such factual areas is not self-evident, and the consequent danger that the level of necessary detail would seem just a jumble of arbitrary information, I first address the principles of law widely recognized as applicable to the matter. This will enable us to see what facts we need for the analysis.

Because of the conclusions I reach, this book sets forth a criticism of U.S. policies and planning as to nuclear weapons and concludes that we need to fundamentally change our approach. For that reason, I develop my analysis, to the extent possible, from the United States’ own mouth, the statements of its authorized representatives. Let’s maximize relevant considerations not in dispute so we can concentrate our efforts on identifying and analyzing areas of disagreement.

Stating the law in the first instance from the mouth of the United States graphically illustrates one key and somewhat surprising point—the extent to which the United States and the critics of nuclear weapons agree on what the law is. To an extraordinary extent, both sides rely on the same principles and rules of law and state the law in largely the same terms.

The United States is a big country, with many people speaking for it. To what sources should we go for authoritative statements of the U.S. position? I use, in the first instance, military manuals of the armed forces of the United States,¹ documents used for the training of U.S. military personnel, the planning and conducting of U.S. military operations, and discipline of military personnel––which hence constitute direct and cogent evidence of what the United States believes the law to be.² I also rely heavily upon the United States’ oral and written statements of the law to the ICJ in the 1996 Nuclear Weapons Advisory Case on the lawfulness of the threat and use of nuclear weapons.

In this Chapter, I review the law the United States recognizes as generally applicable to the use of force in armed conflict. In Chapter 2, as noted, I analyze the United States’ application of this law to nuclear weapons. In Chapter 3, I discuss the ICJ’s 1996 Nuclear Weapons Advisory Decision, reviewing the conclusions and analysis of the Court and of the individual concurring and dissenting judges and examining the extent to which the Court accepted the U.S. position on the issues presented.

In discussing the law as the United States sees it, I focus on areas that are key to the analysis, while identifying areas that are in controversy, including areas where there is disagreement as to what the law is or as to how it should be applied. I also identify certain key statements of the law that the United States appears to back away from when it comes to the application of such law to nuclear weapons. Finally, I highlight factual areas that the applicable law makes relevant, setting forth legal bases for the factual analysis I develop in later chapters.

One note as to terminology: The overriding provisions of the law of armed conflict applicable to nuclear weapons are at times referred to as principles and at times as rules, with the terms often being used interchangeably. When a distinction is made, it is generally in substance that principles are of a broader and rules of a more specific nature, although this distinction has little significance in this context, since, as we will see, the requirements of this body of law are generally stated quite broadly. Given this reality, I generally use these terms interchangeably herein, consistently, as we will see, with the approach taken by the ICJ in the Nuclear Weapons Advisory Case.

SOURCES OF INTERNATIONAL LAW

The most basic of questions will be central to our analysis: What is international law? What are its sources? How binding is it? To what extent is there an effective international enforcement body—and does that matter? To what extent is international law dependent upon the specific agreement of states, or of states particularly affected by the point of law at issue?

Most to the point, if a state has agreed to a rule of law or that rule is established as part of customary international law, is the state bound by all the implications and applications of that rule, even ones with which it disagrees? Or does a state have to agree to the particular application of such a rule? If my analysis is correct, this becomes one of several core issues upon which the legality of the use of nuclear weapons turns. As we shall see, the United States repeatedly, after acknowledging the substance of the leading rules of the law of armed conflict applicable to the use of nuclear weapons, distorts that substance when trying to avoid the application of such rules to the use of nuclear weapons.

The complexity of these issues is reflected in the statement in the Army’s Law of Land Warfare Field Manual that [t]he conduct of armed hostilities on land is regulated by the law of land warfare which is both written and unwritten.³ Difficult as it can be determining the substance and application of written law, the complexities in determining the unwritten law can be even more challenging. The Air Force Manual on International Law quoted Article 38 of the ICJ Statute as the most frequently cited authoritative reference in its articulation of the following sources of international law:

international conventions, whether general or particular, establishing rules expressly recognized by the contesting states;

international custom, as evidence of a general practice accepted as law;

the general principles of law recognized by civilized nations;

subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law.⁴

These are the generally recognized sources or types of international law, including of that subcategory of international law known as the law of war or, more contemporaneously, the law of armed conflict or international humanitarian law. Each of these sources will be integral to our analysis, supplying portions of the overall body of law applicable to the issue at hand.⁵

SUMMARY AS TO APPLICABLE SOURCES

There are numerous international conventions—primarily the Hague and Geneva law, as we shall see—setting forth rules of law limiting the levels of force permissible in armed conflict. So also, many rules of customary law containing such limitations are firmly established in the law of armed conflict and recognized by the United States. Much of the conventional law in this area has either ripened into customary law or from its inception reflected underlying customary rules, so that it is binding even upon non-signatories or states that might now seek to withdraw or condition their consent. The scope of general principles of law recognized by civilized nations as a source of international law is potentially as expansive as the world’s legal systems. In a broad sense, such principles as a source can be conceptualized as the least common denominator of the world’s legal systems, principles essentially recognized across the spectrum of the world’s major legal systems. So too, judicial decisions and academic and other professional writings from throughout the world potentially constitute broad sources of international law helpful in analyzing the matter at hand.

Conventions

International conventions are ostensibly the most concrete of these sources of law. We have the convention, the agreed-to text, before us and can read and interpret it pursuant to familiar principles, although at times the rules set forth in conventions in the law of war area are stated in very general terms. To a considerable extent, the rules of law applicable to nuclear weapons are set forth in conventions and, as noted, disagreements between proponents and opponents of the nuclear weapons regime are essentially on the application of such law to the facts as to nuclear weapons, not on the substance of that law. This is true generally as to the rules of necessity, proportionality, and distinction, the rules upon which we will largely focus.

There are some areas of disagreement as to the reach of certain conventions. For example, the 1925 Geneva Gas Protocol, ratified by the United States in 1975, prohibits the use in war of asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices.⁶ It is recognized that rules embodied in conventions can apply to subsequently introduced technologies, but the proponents and opponents of the nuclear weapons regime disagree on whether this particular language of the Geneva Gas Protocol applies to nuclear weapons. There are also numerous conventions in the environmental protection and human rights areas that some analysts see as applicable to nuclear weapons and others do not. Situations such as these present the familiar legal challenge of how to interpret a document, aided in this instance by the existence of an international convention setting forth modes of interpretation of international treaties and conventions.

Customary Law

Customary law is more amorphous. We do not necessarily have a specifically agreed-to text before us, but rather have to look at state practice and recognized principles of international law and expositions and expressions of such practice and principles by credible sources, official and unofficial. The Naval Commander’s Annotated Handbook describes the development of customary law: When [state military practice] attains a degree of regularity and is accompanied by the general conviction among nations that behavior in conformity with that practice is obligatory, it can be said to have become a rule of customary law binding upon all nations.⁷

The Air Force Manual on International Law quotes Whiteman’s excellent discussion, inter alia, that over time certain international practices have been found to be reasonable and wise in the conduct of foreign relations, in considerable measure the result of a balancing of interests, and have thereby attained the stature of accepted principles or norms, and are recognized as international law or practice.⁸ The manual recognizes that, in finding this and other sources of international law, resort may be had, inter alia, to accepted standards as revealed in agreements or in practice or in authoritative pronouncements.⁹ It bears emphasizing that customary law thus consists not only of practices, but also of standards, principles or norms, essentially rules of law that are recognized as customary international law based on the widespread acceptance and recognition of them by states.

Widely recognized texts and commentaries organize, analyze, and serve as the vehicles for the articulation of this body of law. Indeed, the U.S. military manuals and the U.S. written and oral presentations to the ICJ rely upon generally the same legal texts and commentaries as the opponents of nuclear weapons. The substance of customary international law applicable to the issue at hand is generally not in contention. Rather, the areas of dispute, as noted above, have more to do with the application of such law to the facts. Not that there are no disputes as to the applicable law: The scope of the principles of neutrality and environmental security and of lawful reprisals, for example, are somewhat in contention, but, as an overall matter, the substance of the applicable law in this area is generally non-controversial.

One complicating factor in defining international law results from the overlap of conventional and customary law. As noted, conventional law can both ripen into customary law, including into broadly recognized principles of law, and can also, in the first instance, express preexisting customary law, including broadly recognized principles of law.¹⁰ In either situation, we then have several bodies of law to look to, with particular rules expressed in different mediums.

An example is that presented by Additional Protocol I to the 1949 Geneva Convention, expressing anew, in the nuclear era, earlier conventional and customary law on such subjects as the rules of proportionality, necessity, and distinction and the law as to reprisals. Additional Protocol I also prohibits any methods or means of warfare that are intended, or may be expected, to cause widespread, long-term and severe damage to the natural environment.¹¹ The United States has signed but not ratified this Protocol.¹² In signing this Protocol, the United States, along with other nuclear powers, interposed a formal understanding that the new rules introduced by the Protocol are not intended to have any effect on and do not regulate or prohibit the use of nuclear weapons.¹³

This situation raises questions as to how we sort out such considerations as the following: the continuing requirements of underlying customary law and the impact, if any, of such law on Additional Protocol I; the scope of applicability of the newly introduced provisions of the Protocol, facially and based upon the drafting history; and the effect of the understandings by the United States and other nuclear powers as to the non-applicability of the Protocol to nuclear weapons.

Generally Accepted Principles of Law

General principles of law recognized by civilized nations, as a source of international law, are both more and less amorphous than customary law: More amorphous in the sense that, unlike customary law, they are not so readily available in standard international law research materials; instead, generally one must canvass the domestic law of individual states to find them and the effort can be quite challenging and the results indefinite. Less amorphous in that lawyers as a whole know how to deal with this kind of law, at least from within their own individual legal systems.

General principles of law recognized by civilized nations are a primary source of international law. The Naval Commander’s Annotated Handbook states: In the past half century there has been a marked tendency to include among the sources of the rules of warfare certain principles of law adopted by many nations in their domestic legislation.¹⁴ The handbook quotes the decision of the United States Military Tribunal in The Hostages Case:

The tendency has been to apply the term customs and practices accepted by civilized nations generally as it is used in international law, to the laws of war only. But the principle has no such restricted meaning. It applies as well to fundamental principles of justice which have been accepted and adopted by civilized nations generally. In determining whether such a fundamental rule of justice is entitled to be declared a principle of international law, an examination of the municipal laws of states in the family of nations will reveal the answer. If it is found to have been accepted generally as a fundamental rule of justice by most nations in their municipal law, its declaration as a rule of international law would seem to be fully justified.¹⁵

Such general principles recognized by individual legal systems appear to be a largely unexplored and under-utilized source of international law. The existence of this source of international law is non-controversial, but its potential impact upon the issues we are examining remains largely unexplored. In Part II, I review a number of rules of law that appear to be generally recognized by the United States and many other states throughout the world and hence may rise to the level of general principles of domestic law that are so widely recognized as to constitute binding rules of international law. I focus particularly on general principles potentially providing insight as to the legal significance of various levels of probability that a state’s use of nuclear weapons would potentially result in unnecessary, disproportionate or indiscriminate injury to noncombatants, neutrals and other protected persons and objects and upon principles having to do with prerequisites for a per se rule.

Consent lies at the basis, at least initially, of international law. Recognizing general principles of law recognized by civilized nations as a primary source of international law,¹⁶ the Air Force Manual on International Law emphasizes that this source, like others, is based on consent, stating that international law derives its basis primarily from state practice and state consent represented in the form of treaties, custom or general principles of law acknowledged by all states or by all principal legal systems.¹⁷ The element of consent with respect to generally accepted principles is inherent in their wide acceptance by states. Indeed, as noted, such wide acceptance may result in the formation of customary international law as well.¹⁸

It will become relevant to note that consent in this latter sense is more of a constructive than an express nature. The acceptance by all principal legal systems of a principle of law as itself constituting the establishment of that principle as a rule of international law is conceptually different from the more familiar notion of states’ formulating international law through negotiating and subscribing to treaties and multinational conventions or engaging in or acknowledging particular state practices in the international arena over extended periods of time. The important thing to note for present purposes is that the United States recognizes this category of widely recognized principles of law as a potential source of binding international law.

Subsidiary Sources of International Law

In language that will bear upon our analysis, and particularly upon my reliance on decisions of a number of U.S. and other domestic courts, the Air Force Manual on International Law refers to decisions of national and international courts and tribunals and writings of qualified authorities as subsidiary sources of international law¹⁹ and cites with approval Whiteman’s statement that authoritative pronouncements as to international law may include [d]ecisions of local courts and tribunals as well as international judicial tribunals and international arbitral bodies, according to their competence, and teachings of universities and the writings of publicists, depending upon their merit.²⁰

The Naval Commander’s Annotated Handbook states that evidence of the law of armed conflict may also be found in national military manuals, judicial decisions, the writings of publicists, and the work of various international bodies.²¹

The Air Force Manual on International Law recognizes that the subsidiary category of judicial decisions and scholarly and professional writings exists not only as a reflection of existent law but also as an expression of it.²² The manual quotes the U.S. Supreme Court decision in The Paquete Habana:

The works of jurists and commentators on the subject of international law] are resorted to by judicial tribunals, not for the speculations of their authors concerning what the law ought to be, but for trustworthy evidence of what the law really is.²³

U.S. Recognition of General Principles as Binding

As noted, the term general principles is used to refer both to general principles and norms of international law that are encompassed within customary international law and to general principles of domestic law so widely recognized by civilized nations that they arise to the level of international law.

The United States has recognized that generally accepted principles of law can constitute a sufficient basis for the unlawfulness of the use of a particular weapon or type of weapon. The Air Force Manual on International Law states that the use of a weapon may be unlawful based not only on expressed prohibitions contained in specific rules of custom and convention, but also on those prohibitions laid down in the general principles of the law of war.²⁴ Similarly, in discussing how the lawfulness of new weapons and methods of warfare is determined, the manual states that such determination is made based on international treaty or custom, upon analogy to weapons or methods previously determined to be lawful or unlawful, and upon the evaluation of the compliance of such new weapons or methods with established principles of law, such as the rules of necessity, distinction, and proportionality.²⁵

Focusing on the broader meaning of general principles of law, the manual notes that the International Military Tribunal at Nuremberg in the case of the Major War Criminals found that international law is contained not only in treaties and custom but also in the general principles of justice applied by jurists and practiced by military courts.²⁶

This point as to the sufficiency of general principles as a basis for determining the unlawfulness of the use of particular weapons becomes a key acknowledgment by the United States—and one, as we shall see, that the United States backed away from before the ICJ in arguing that the use and threat of use of nuclear weapons cannot be unlawful because the United States, through its policy of deterrence, has continuously asserted the lawfulness of such use and threat of use and has not agreed to their prohibition under international law.

Contrary State Practice as Not Vitiating Treaty Obligations

There is no doubt that treaty obligations generally remain binding even in the face of contrary state practice. The Air Force Manual on International Law states that the practice of states does not modify the legal obligation to comply with treaty obligations since such obligations are contractual in nature.²⁷

This rule—akin to the proposition that a high crime rate does not invalidate the applicable criminal laws—makes perfect sense. But the United States essentially overrode it in arguing to the ICJ that the United States is not potentially bound by treaty obligations that could be interpreted as precluding the use and threat of use of nuclear weapons since the United States’ practice of the policy of deterrence has been inconsistent with such obligation.

Specifically, the United States argued that its practice of deterrence—involving, as it does, the threat of the use of nuclear weapons—precluded the application to such weapons of treaty obligations and commitments that would preclude the threat and use of such weapons.

Relevant Sources of Law

All four traditional sources of international law—conventions, customary law, general principles of law recognized by civilized nations, and judicial decisions and writings of qualified experts—will be relevant to our analysis. The principles of law upon which I primarily focus in this book, those of necessity, proportionality, and distinction, along with the corollary requirement of controllability, are established rules of customary law and are also embodied in widely adopted conventions. They are also widely recognized in judicial decisions and writings of qualified experts and are in many respects reflective of the domestic law of many states.

NATURE AND PURPOSES OF THE LAW OF ARMED CONFLICT

The foregoing tells us where international law is located, how we can find it. But once we find it, we are going to have to interpret it in order to be able to apply it. Inevitably, there will be ambiguities as to the text of conventional and the content of customary and other law. How do we then proceed?

It is a fundamental insight and indeed rule of law, implicit in the limits of human expression, that law—be it statute, case precedent, international treaty, general principle—is to be interpreted in light of its purpose. This is fundamentally a question of ascertaining intent, either specific or constructive: What was intended by this rule of law or, if the drafters or other originators of the rule did not focus on this particular application, what would they have intended, had they focused on it?

For this reason, our notions of the purposes of the law of armed conflict become integral to our interpretation and application of this law to the issue at hand.

The purpose of the law of armed conflict is to temper the violence of war, both for idealistic and pragmatic reasons: Idealistically, to minimize death and destruction out of compassion. Pragmatically, to protect one’s own military and civilian personnel and objects from acts of violence that one is prohibited from inflicting upon enemy persons and objects.

Underlying is a core idea as to the nature of international political relations: that war exists not in isolation but in relation to peace, and that the two, war and peace, represent the human political condition. War is by nature limited not total; in the fullness of time, it will give way to peace. Life will prevail over death, reason over the dark forces of human nature. The purpose of war is to create an acceptable peace. The purpose of the law of war is to impose rationality on war so that the peace may be restored.

The Army’s Operational Law Handbook states:

A. The fundamental purposes of the [law of armed conflict] are humanitarian and functional in nature. The humanitarian purposes include:

Protecting both combatants and noncombatants from unnecessary suffering;

Safeguarding persons who fall into the hands of the enemy; and

Facilitating the restoration of peace.

B. The functional purposes include:

Ensuring good order and discipline;

Fighting in a disciplined manner consistent with national values; and

Maintaining domestic and international public support.²⁸

The Air Force, in its manual, The Military Commander and the Law, sets forth the following purposes of this body of law:

Motivate the enemy to observe the same rules (reciprocity)

Limit the effects of the conflict (reduce damages and casualties)

Guard against acts that violate basic tenets of civilization, protect against unnecessary suffering

Protect combatants and noncombatants from unnecessary suffering

Safeguard fundamental rights of combatants and noncombatants

Provide advance notice of the accepted limits of warfare, and may prevent the conflict from becoming worse or motivate the enemy to surrender

Make it easier to restore peace when the conflict is over.²⁹

The Army’s Law of Armed Conflict Deskbook emphasizes the serious nature of this body of law, making it clear that it goes beyond the aspirational:

Unifying Themes of the Law Of Armed Conflict

A. Law exists to either prevent conduct or control conduct. These characteristics permeate the law of armed conflict, as exemplified by its two prongs: Jus ad Bellum serves to regulate the conduct of going to war, while Jus in Bello serves to regulate or control conduct within war.

B. Validity. Although critics of the regulation of warfare cite examples of violations of the law of armed conflict as proof of its ineffectiveness, a comprehensive view of history provides the greatest evidence of the overall validity of this body of law.

History shows that in most cases the law of armed conflict works. Despite the fact that the rules are often violated or ignored, it is clear that mankind is better off with than without them. Mankind has always sought to limit the effect of conflict on combatants and noncombatants and has come to regard war not as a state of anarchy justifying infliction of unlimited suffering but as an unfortunate reality which must be governed by some rule of law. This point is illustrated in Article 22 of the 1907 Hague Regulations: the right of belligerents to adopt means of injuring the enemy is not unlimited. This rule does not lose its binding force in a case of necessity.

Regulating the conduct of warfare is ironically essential to the preservation of a civilized world. General MacArthur exemplified this notion when he confirmed the death sentence for Japanese General Yamashita, writing: The soldier, be he friend or foe, is charged with the protection of the weak and unarmed. It is the very essence and reason of his being. When he violates this sacred trust, he not only profanes his entire cult but threatens the fabric of international society.³⁰

The Naval Commander’s Annotated Handbook states that the essential purpose of the law of war is to provide common ground of rationality between enemies, adding, The law of armed conflict is intended to preclude purposeless, unnecessary destruction of life and property and to ensure that violence is used only to defeat the enemy’s military forces.³¹

The handbook goes on to state:

The law of armed conflict inhibits warfare from needlessly affecting persons or things of little military value. By preventing needless cruelty, the bitterness and hatred arising from armed conflict is lessened, and thus it is easier to restore an enduring peace. The legal and military experts who attempted to codify the laws of war more than a hundred years ago reflected this reality when they declared that the final object of an armed conflict is the re-establishment of good relations and a more solid and lasting peace between the belligerent States.³²

The Air Force Manual on International Law states that the law of armed conflict is inspired by the humanitarian desire of civilized nations to diminish the effects of conflicts and represents an attempt to prevent degeneration of conflicts into savagery and brutality, thereby facilitating the restoration of peace and the friendly relations which must, at some point, inevitably accompany or follow the conclusion of hostilities.³³

The manual adds that the law of armed conflict has been said to represent in some measure minimum standards of civilization.³⁴ Noting that the law of armed conflict developed from an amalgam of social, political and military considerations, the manual states that the primary basis for the law, and the principal reason for its respect, is that it generally serves the self-interest of everyone subject to its commands.³⁵ The manual further notes the principle set forth in the Lieber Code (discussed below) that military necessity does not justify any act of hostility which makes the return to peace unnecessarily difficult.³⁶

The manual quotes the Chairman of the Joint Chiefs of Staff:

The Armed Forces of the United States have benefited from, and highly value, the humanitarianism encompassed by the laws of war. Many are alive today only because of the mutual restraint imposed by these rules, notwithstanding the fact that the rules have been applied imperfectly.³⁷

The Army’s Commander’s Handbook on the Law of Land Warfare states:

The main purposes of LOAC are:

Protecting combatants, noncombatants, and civilians from unnecessary suffering;

Providing certain fundamental protections for persons who fall into the hands of the enemy, particularly prisoners of war, military wounded and sick, and civilians;

Facilitating the restoration of peace;

Assisting the commander in ensuring the disciplined, ethical, and effective use of military force;

Preserving the professionalism and humanity of combatants; and

Preventing the degeneration of warfare into savagery or brutality.³⁸

The seriousness of the law of armed conflict was portrayed most vividly by the United States Military Tribunal in the Krupp trial:

It is an essence of war that one or the other side must lose and the experienced generals and statesmen knew this when they drafted the rules and customs of land warfare. In short, these rules and customs of warfare are designed specifically for all phases of war. They comprise the law for such emergency. To claim that they can be wantonly—and at the sole discretion of any one belligerent—disregarded when he considers his own situation to be critical, means nothing more or less than to abrogate the laws and customs of war entirely.³⁹

Emphasizing the broad scope of international law, the Air Force Manual on International Law adopts language of Whiteman to the effect that international law is evidenced by the general norms of civilization.⁴⁰

It is also in the nature of the law of war that it is dynamic, evolving out of human experience and necessity and advancing with the progress of civilization. The Air Force Manual on International Law recognizes as one of the most descriptive definitions of international law Hackworth’s statement:

International law . . . is a system of jurisprudence which, for the most part, has evolved out of the experiences and the necessities of situations that have arisen from time to time. It has developed with the progress of civilization with the increasing realization by nations that their relations inter se, if not their existence, must be governed by and dependent upon rules of law fairly certain and generally reasonable. . . .⁴¹

The manual similarly relies upon Whiteman’s definition, which also emphasizes the dynamic nature of international law:

International law is the standard of conduct, at a given time, for states and other entities subject thereto. It comprises the rights, privileges, powers, and immunities of states and entities invoking its provisions, as well as the correlative fundamental duties, absence of rights, liabilities and disabilities. International law is, more or less, in a continual state of change and development.⁴²

POLITICAL NATURE OF THE LAW OF ARMED CONFLICT

Observing a point of note to this issue, The Air Force Manual on International Law states that international law like domestic law, is the product of political process.⁴³ Relatedly, I argue that, with the demise of the Soviet Union and the emergence of a discordant multi-polar world and enhanced threats posed by terrorist groups, the current nuclear weapons regime—with its legitimization of nuclear weapons to support deterrence—is no longer in the political or military interests of the United States.

BINDING NATURE OF INTERNATIONAL LAW

The U.S. Constitution provides that treaties entered into by the United States are the supreme Law of the Land.⁴⁴ The Air Force Manual on International Law notes that state and federal courts have declared international law to be part of the law of the land.⁴⁵ The manual states that the United States is bound to follow customary international law not because a treaty requires it, but because international law imposes the obligation on all states.⁴⁶

The military manuals of the U.S. armed forces reiterate the United States’ recognition of the binding nature of international law and widely reflect the belief that this body of law and the restraints it imposes are in the interest of the United States. The Air Force Manual on International Law states, The primary basis for the law, and the principal reason for its respect, is that it generally serves the self-interest of everyone subject to its commands.⁴⁷ The Naval Commander’s Annotated Handbook states, At all times, a commander shall observe, and require their command to observe, the principles of international law.⁴⁸

The Air Force Manual on International Law further notes that nations have many of the same reasons to obey international law as individuals do to follow domestic law, including "foreseeability, reciprocity, approbation