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International Customary Law and Antipersonnel Landmines: Emergence of a New Customary Norm, Landmine Monitor Report 1999

International Customary Law and Antipersonnel Landmines: Emergence of a New Customary Norm

Susan Benesch, Glenn McGrory, Cristina Rodriguez, Robert Sloane

Allard K. Lowenstein International Human Rights Clinic, Yale Law School

I. Why Is Customary International Law Important For a Ban on Antipersonnel Landmines?

There are two primary sources of international law, treaties and custom.1 Custom -- law that develops from commonly agreed-upon rules of behavior -- 2 is important for the ban against antipersonnel landmines, because of a critical attribute that distinguishes it from treaty law. Whereas a treaty legally binds only those states which are parties, in most cases customary international law constrains all states,3 even those that have not agreed to it.4

If the Mine Ban Treaty’s 5 prohibitions on the production, use and transfer of landmines become part of customary international law, then, states that are not party to the treaty will bear a legal obligation to obey those prohibitions. For that reason, now that a ban on antipersonnel landmines is established as treaty law, we believe the next step is to work toward the crystallization of a customary international law ban on landmines.

To that end, this paper will explain the nature of customary law and its formation, and then will examine the state of that law with respect to landmines. We will consider the following questions: is there a customary international norm6 against the use of antipersonnel landmines now, and if not, can we expect such a norm to emerge in the future? If so, when?

The most powerful force toward the establishment of custom on landmines is the Mine Ban Treaty itself. Treaties are often the first step in the formation of custom, especially when, as in this case, they express consensus on the part of an extraordinary number of states. 7 “Not only do [treaties] carve out law for the immediate parties, but they also have a profound impact upon general customary law for nonparties,”8 as the scholar Anthony D’Amato has noted. Once a rule attains the status of customary international law, states may not unilaterally repudiate it,9 and newly emerging states will be deemed to accede to the rule as a condition of statehood.10

This paper will show that there is rapid momentum toward a customary norm against the use of antipersonnel landmines. It is difficult to predict how quickly the norm will crystallize, and any prediction would immediately become the subject of debate, but we think most legal scholars and practitioners would agree that a customary prohibition against landmines will crystallize in the near future.

The International Campaign to Ban Landmines and other advocates can use customary law to argue that states should sign the treaty. If a ban on landmines is likely to emerge soon as customary international law, as we argue, there are two good reasons for states to sign and ratify the convention and begin work toward compliance. First, they will avoid being caught in violation of a binding customary norm. Second, if states will be constrained by the new custom anyway, they will do better to enjoy the benefits of participation in the Landmine Ban treaty regime, including the “exchange of equipment, material and scientific and technological information” for mine-clearance, and the opportunity to propose amendments to the Convention.11

These arguments are becoming stronger with each extra signature, ratification, or decision to forsake the use of antipersonnel landmines, since those steps bring the international community closer to a customary norm against the weapons.

What is Customary International Law and How is it Formed?

According to Oppenheim, one of the most widely-recognized authorities in international law, a custom is “a clear and continuous habit of doing certain actions which has grown up under the aegis of the conviction that these actions are, according to international law, obligatory or right.”12 Custom is law not because it is printed on paper, but because states practice it, and because their officials believe it to be law.13 A sometimes slippery concept, custom plays an especially large role in international law, where there is no legislature to codify law.(Treaty-writing is often a slow and unwieldy process.)

The formation of custom – how and when a new norm becomes part of customary international law – is the reason for custom’s ‘slippery’ reputation, since it is so difficult to pinpoint. It has become the subject of substantial debate.14 In particular, scholars and judges debate the relationship between customary international law and treaties, focusing on when and how treaties can give rise to custom.

There have been undeniable changes in the formation of international treaty law, brought on in large measure by the human rights movement. The Mine Ban Treaty itself is one of the most prominent demonstrations of new methods for drafting international treaties, and for seeing them into law.15 The Mine Ban Treaty proved that treaties can be negotiated faster than ever before, but this does not necessarily mean that custom on landmines will form faster. And since treaties are more tangible than custom, it is easier to track changes in the formation of treaties than changes in the formation of custom.

The key questions for our purposes are: what actions or statements, by states or other bodies, are now considered evidence of custom? Where is the threshold between custom and non-custom, if it is possible to find one? To answer these questions, this section will outline the traditional understanding of custom and its formation. Then it will examine cases in which custom forms before a practice has become universal, since that is likely to happen in the case of the antipersonnel landmines ban. We willthen consider whether any state can exempt itself from a future customary norm against antipersonnel landmines by becoming a ‘persistent objector.’ Finally, we will discuss the ways in which treaties can give rise to customary international law.

The formation of custom: practice and opinio juris

1. General Standards

The traditional starting-point for discussions of customary international law is also the most widely-recognized statement as to the sources of international law: Article 38(1) of the Statute of the International Court of Justice.16 The article lists four sources of law:

a. international conventions, whether general or particular, establishing rules expressly recognized by the contesting States;

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

c.he general principles of law recognized by civilized nations;

d. 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.

Since custom is not codified or printed, like a treaty, it must be identified in a different and more complex way. The formulation quoted in Article 38(1)(b), “international custom as evidence of a general practice accepted as law,” includes the two classic requirements for customary international law: practice and opinio juris. 17 Practice refers to the conduct of a state -- whether it uses antipersonnel landmines, for example. Opinio juris, short for opinio juris sive necesitatis, can be translated as ‘a conviction that a rule is obligatory.’ It refers to state officials’ sense of a legal obligation to follow a certain practice, and it is sometimes called the ‘belief element.’

Practice can be universal and still not establish custom, if there is no opinio juris in favor of the practice. Widespread practice without opinio juris is often called ‘usage’. Examples are ceremonial salutes at sea and the cancellation of parking tickets issued to diplomatic cars.18 While states commonly do these things, no one would claim that they must do them. This distinction between usage and custom reaches back to the French scholar Francois Gény’s use of the phrase to differentiate legal custom from usage or mere social custom.19

International courts have repeatedly affirmed the critical role played by opinio juris in custom. In the 1927 Lotus Case, the Permanent Court of International Justice considered whether custom had formed on a question of jurisdiction, after a French ship and a Turkish ship collided, killing eight Turkish nationals. Turkey began to prosecute the first officer of the French ship, and France disputed Turkey’s jurisdiction to try him. The Court was asked to decide whether customary international law prohibited Turkey from trying the French officer. The fact that France had ‘abstained’ from trying him did not indicate custom, the court found, since there was no evidence of opinio juris. It held that “only if such abstention were based on [states’] being conscious of having a duty to abstain would it be possible to speak of an international custom.”20

In 1969 the International Court of Justice (which succeeded the earlier Permanent Court) affirmed the role of opinio juris in the North Sea Continental Shelf Cases. To decide the cases, the Court had to determine which provisions of the 1958 Geneva Convention on the Continental Shelf had become customary law by 1969, only 11 years after the Convention. It held that for a treaty provision to become customary, “two conditions must be fulfilled. Not only must the acts concerned amount to a settled practice, but they must also be such, or be carried out in such a way, as to be evidence of a belief that this practice is rendered obligatory by the existence of a rule of law requiring it…The states concerned must therefore feel that they are conforming to what amounts to a legal obligation.” 21 In 1986, the Court reaffirmed this notion of opinio juris, when it decided that under customary international law, the United States’ mining of Nicaraguan harbors and financial support for the contra war was illegal. In that decision, called the Case Concerning Military and Paramilitary Activities In and Against Nicaragua, the Court considered whether the principle of non-intervention in the affairs of other states had become custom. Regarding state actions that constitute custom, it held that “Either the States taking such action or other States in a position to react to it, must have behaved so that their conduct is ‘evidence of a belief that this practice is rendered obligatory by the existence of a rule of law requiring it.”22

Evidence of opinio juris can be found in any of several types of sources. Comments by state officials may indicate a sense of legal obligation to follow or not follow certain conduct. Opinio juris can also be found in General Assembly resolutions, and in other unilateral or collective statements. In the 1986 Nicaragua case, the International Court of Justice observed that state consent to General Assembly resolutions and other statements expressing norms embodied in a treaty should not be understood as mere “reiteration or elucidation” of treaty commitments. Rather, such expressions provide additional evidence that the state accepts the validity of thesenorms, and consequently, also evince an opinio juris supporting their status as customary international law. The “attitude referred to expresses an opinio juris respecting such rule (or set of rules), to be thenceforth treated separately from the provisions, especially those of an institutional kind, to which it is subject on the treaty-law plane . . .”23

It is important to note that an apparent contradiction, or Catch-22 is inherent in the doctrine: opinio juris is a prerequisite for customary law, but in order to produce opinio juris, state officials must be convinced that the law already exists. The paradox has been widely debated by scholars, some of whom dispute it. In any case the apparent paradox has “not prevented acceptance of customary law essentially as here defined.”24

Having described the nature of the traditional requirements for custom, we can now ask, to what extent is it possible to quantify them? How many states must follow a certain practice in the belief that it is law, for international customary law to crystallize? We know of no credible numeric rule. “How many States are required to establish ‘general’ practice and how frequent, numerous and consistent the practice must be are questions which cannot be answered in categorical propositions,” according to the scholar Oscar Schachter. “Generality, frequency, density, consistency, duration are in principle required but whether they are met in regard to a specific rule depends on the circumstances of the case." 25 Even if it is not possible to say that custom will have formed when a certain precise number of states has signed or ratified the Landmine Ban, we can draw clear conclusions about other requirements for custom, and, more encouragingly, about non-requirements.

No minimum length of time is required for the formation of custom

There is no minimum length of time required for the formation of custom, so the speed of the Landmine Ban process will not hinder the ban’s development into custom. In the North Sea Continental Shelf Cases, the International Court of Justice dismissed time as a requirement for the emergence of custom from conventions. The Court held that “even without the passage of any considerable period of time, a very widespread and representative participation in the convention might suffice of itself, provided it included that of States whose interests were specially affected.”26

Some scholars even argue that custom can form “instantly” on a new body of law, where there is no prior practice that has to change for custom to crystallize, and where a large number of states express unanimity. The most commonly cited example is theinternational law on outer space 27. Instant custom cannot be said to have formed in the case of antipersonnel landmines, since there was longstanding practice contrary to the new norm and since states did not reach consensus all at once.

On the lack of a time restriction, the scholar Ian Brownlie has commented: “Provided the consistency and generality of a practice are proved, no particular duration is required: the passage of time will of course be a part of the evidence of generality and consistency. A long (and, much less, an immemorial) practice is not necessary, and rules relating to airspace and the continental shelf have emerged from fairly quick maturing of practice.”28 The scholar Malcolm Shaw concurs: “in international law there is no rigid time element and it will depend upon the circumstances of the case and the nature of the usage in question.”29

Not all states must consent to a norm of customary international law

There is also “broad agreement that general custom does not require universal consent of States.”30 In the Nicaragua case described above, the International Court of Justice held specifically, “The Court does not consider that, for a rule to be established as customary, the corresponding practice must be in absolutely rigorous conformity with the rule. In order to deduce the existence of customary rules, the Court deems it sufficient that the conduct of States should, in general, be consistent with such rules, and that instances of State conduct inconsistent with a given rule should generally have been treated as breached of that rule, not as indications of the recognition of a new rule.” 31

Therefore the landmines ban can become custom, according to this formulation, even while some states still refuse to sign the land mine treaty. Those states would then be bound by the new custom.

It seems particularly important that states “whose interests are specially affected” comply with the Landmine Ban, for its provisions to become customary. Even while dismissing the importance of time as a requirement for custom, the International Court of Justice twice emphasized, in the North Sea Continental Shelf Cases, that “specially affected” states would have to be parties to the 1956 Convention, for it to becomecustomary international law.32 And in its 1996 Advisory Opinion on nuclear weapons, the Court identified states that have nuclear weapons as a specially-affected class.33 By analogy in the case of the Mine Ban Treaty, specially-affected states would probably be producers and users of landmines, like Russia, China, and the United States.

The formation of custom can be based on opinio juris more than on state practice

Many judges, scholars and legal practitioners say that opinio juris should be more important than practice in the formation of custom. These jurists argue that a rule need not be universally followed before it can be anointed as an international customary norm – it just has to be universally, or generally, defended. This argument could be very useful in the case of antipersonnel landmines, if states cease to defend the use of landmines before they actually stop using them. This may be true of Angola, for example.

The call for emphasis on opinio juris is not new. Already in 1967, Prof. R.R. Baxter wrote, “Reliance on a multilateral treaty as evidence of customary international law is not conditional on any demonstration that the signatory States have actually observed the norms of the treaty for any length of time. The process of establishing the state of customary international law is one of demonstrating what States consider to be the measure of their obligations. The actual conduct of States in their relations with other nations is only a subsidiary means whereby the rules which guide the conduct of States are ascertained.”34 In that view, practice is subsidiary to opinio juris.

Both the International Court of Justice and the International Criminal Tribunal for the Former Yugoslavia (ICTY) have used this view of opinio juris in major recent decisions on the formation of international custom. In both cases, the courts held that custom had crystallized, based on evidence of opinio juris, not practice.

In the 1986 Nicaragua case, the International Court of Justice held that the United States had violated customary international laws against the use of force against another state, against intervention in another state’s affairs, and against violating another state’s sovereignty. Since laws like the ban on non-intervention had been violated frequently and famously, especially during the Cold War, the Court might have had difficulty arguing for custom based on practice. Instead it relied heavily on opinio juris. The Court decided that there was customary law against intervention although many states had intervened in others’ affairs, because the intervening states had not “justified their conduct by reference to a new right of intervention or a new exception to the principle of its prohibition.”35

That is, the intervening states’ practice did not conform to the principle, but their opinio juris did, so the Court concluded that there was customary law. This could apply to the Landmines Ban. If it becomes possible to argue that although some states use landmines, they do not defend the practice as a ‘right’ or an ‘exception to the principle of …prohibition,’ to borrow language from the Nicaragua case,36 it would be possible to argue that there is customary law against the use of landmines, following the reasoning of Nicaragua.

Similarly, in its Appeals Chamber decision in the Tadic case, the ICTY relied overwhelmingly on government statements, rather than evidence of state practice, to decide in its decision in the case of Dusko Tadic. 37 As the scholar Theodor Meron has pointed out, the Court used various indications of opinio juris, including military manuals, to conclude that the Court had jurisdiction to preside over cases dealing with war crimes committed in internal armed conflicts, not only international wars.38

Many provisions of international treaty law, especially those regarding human rights, have given rise to undisputed custom even though they are frequently violated. One example is the text of the Universal Declaration of Human Rights, a code that is lavishly praised but is still not ‘practiced’ by many states. As the scholar Louis Sohn put it, “The Declaration, as an authoritative listing of human rights, has become a basic component of international customary law, binding all states, not only members of the United Nations.”39 Even a relatively conservative source like the Restatement (Third) of Foreign Relations Law of the United States holds that “[a] state violates international law if, as a matter of state policy, it practices, encourages or condones” cruelties against its own nationals including torture, systematic racial discrimination, and prolonged arbitrary detention.40 All of these human rights violations are prohibited by the Universal Declaration and other treaties,41 and there is general agreement that they have become customary law, yet unfortunately they are common in many states.

Opinio juris can also change quickly, according to some scholars. They argue that since World War II, prospective inquiry reflecting the massive proliferation of treaty law has supplanted the retrospective inquiry that was the standard method of identifying customary international law before. According to the scholar Ted Stein, “Whereas traditionally, [t]he question of what states ought to do was answered primarily by asking what they have done…. For today’s foreign ministry lawyer, the key question is whether to place reliance upon a rule stated in some treaty or resolution….Correspondingly, opinio juris is no longer seen as a consciousness that matures slowly over time …, but instead as a conviction that instantaneously attaches to a rule believed to be socially necessary or desirable.”42

These precedents suggest that a customary norm against antipersonnel landmines could develop, even before all states cease to use the weapons. By analogy, torture has never ceased as a practice, but that did not stop a customary norm against torture from developing: what counted was the development of opinio juris. In sum, when the ban on landmines gathers such strength that no state’s officials are willing to defend the use of landmines in any circumstances, it will be possible to argue that the ban is customary international law, like the prohibition against torture. Of course substantial evidence of changing practice is still necessary, otherwise the norm would be divorced from reality. There has already been considerable change in landmines practice, as we will discuss below.

No state can be a ‘persistent objector’ to a customary ban on antipersonnel landmines

As described above, once a rule attains the status of customary international law, states may not unilaterally repudiate it,43 and newly emerging states will be deemed to accede to the rule as a condition of statehood.44 This principle admits of one exception, however, the so-called “persistent objector” rule: “[a] state that has persistently objected to a rule is not bound by it, so long as the objection was made manifest during the process of the rule’s emergence45 The “persistent objector” exception to customary international law derives from recognition that international law emanates from the consent, whether tacit or express, of independent sovereign states.Consequently, a state that has “manifestly and continuously”46 objected to an evolving norm of customary international law cannot be bound by it.47

There are almost certainly no persistent objectors to the Mine Ban Treaty. States that wish to claim exemption from emerging norms must make their objections “manifestly and continuously,” and prior to the moment when these norms crystallize into clear customary international law. Where, as here, a widely subscribed treaty is contributing to the rapid crystallization of a customary norm, that means a state would need to have compiled a record of steady objection to the treaty.48

It would seriously damage the treaty’s chances of giving rise to customary law if any of the three major user and producer states, Russia, China and the United States, was a persistent objector. We contend that this is not possible. The United States, far from clearly and continuously manifesting its dissent from provisions of the Mine Ban Treaty, has been a strong supporter of many of the treaty’s provisions. The United States cannot credibly claim persistent objector status.

Nor does it appear that any other nation has “clearly and continuously” dissented from the terms of the Mine Ban Treaty or its emerging concomitant customary international law norms. In December 1996, the United Nations General Assembly, by a vote of 156-0, with ten abstentions, passed a resolution urging states to “pursue vigorously an effective, legally binding international agreement to ban the use, stockpiling, production and transfer of antipersonnel landmines” and “call[ing] upon States that have not yet done so to declare and implement such band moratoriums and restrictions . . . at the earliest possible date.”49 China and Russia, which have not, to date, signed the treaty, nonetheless joined the United States at a landmine conference held at the time of the treaty ceremony, in which all three nations “indicated that they will eventually comply with most of the treaty’s regulations.”50 And finally “[w]hile some [states] in the Middle East/North Africa region are very hostile to a landmine banat this time—including Egypt, Iraq, Israel, Libya, and Syria—nearly every country has expressed support for a ban at some point in the future.”51

Treaties as a Source of Custom

As mentioned above in Section I, treaties are a major source of customary international law, because they are an important indicator of state commitment to emerging norms. This gives reason to hope that the Mine Ban Treaty will give rise to custom.

The principle that customary law can develop from the provisions of treaties is so well-established that it is codified in the Vienna Convention on the Law of Treaties.52 It has also been repeatedly recognized by the International Court of Justice, and by many scholars.53 In section II(A)1 above, we have already mentioned the Nicaragua case, in which the Court found that custom against intervention in the affairs of other states had emerged from the U.N. Charter. As the Court pointed out in that case, customary international law need not be identical to the provisions of the treaty from which it emerges. Therefore if custom develops against landmines, it is possible that its scope may ultimately be broader than the treaty itself, so that non-party states would be bound by a more stringent norm.

Treaties dealing with the conduct of war, especially, have given rise to a great deal of customary international law. For example in the war crimes case of United States v. Von Leeb (“The High Command Case”) the Nuremberg Tribunal concluded that the 1929 Geneva Prisoners of War Convention could be binding on Nazi Germany with respect to the Soviet Union, although the Soviet Union had not been a party to the convention. Only 12 years had passed since the convention had been adopted, but the Tribunal determined that it was already customary law.54 Similarly, many provisions of the more recent Geneva Protocols of 1977 have developed into customary international law, according to the scholar and judge Antonio Cassese, Theodor Meron and others.55

The provisions of human rights treaties have also contributed to a substantial body of customary international law, as many authorities including the U.S. State Department have recognized. In a brief submitted to the U.S. court hearing the case of Filartiga v. Pena-Irala, in which the family of a man tortured to death in Paraguaybrought civil suit against the torturer, the State Department adopted the view that there is a customary international norm against torture. Relying heavily on opinio juris, the State Department noted that both multilateral treaties and international custom evince a “universal condemnation of torture.” 56

What is the Existing State of Customary International Law Regarding an Antipersonnel Landmines Ban?

Although the campaign to ban antipersonnel landmines is of recent origin, the international community has long concerned itself with regulating the conduct of war so that it does not unduly harm civilians. Much of this law has already become customary, as mentioned in the previous section, and it could arguably be deemed to prohibit antipersonnel landmines. Therefore a framework of customary international law against landmines already exists, even if there is not yet an explicit customary ban against them.

Three principles of longstanding, customary international humanitarian law can be applied to antipersonnel landmines, and arguably prohibit them. Those principles are: the rule against needlessly aggravating human suffering, the rule against indiscriminate weapons (those that fail to distinguish between civilians and soldiers), and the rule that weapons must be militarily necessary. All three have been codified in the laws of war, also known as humanitarian law. These laws are briefly described below.

The Declaration of St. Petersburg of 1868, in which the parties renounced the use of projectiles below a certain weight, was an early international attempt to limit the way in which war is conducted. The Declaration called on states not to use certain weapons that caused (militarily) needless suffering, stating that “the only legitimate object which states should endeavor to accomplish during war is to weaken the military force of the enemy . . . .”57 The next major codification of the laws of war emerged from the international Hague Conferences of 1899 and 1907. The Hague Declarations and Treaties of those dates established principles against weapons that indiscriminately or disproportionately kill and wound civilians. The Hague Convention (II)58

The four Geneva Conventions for the Protection of War Victims, promulgated in 1949, went into more detail, attempting to protect wounded and sick combatants, prisoners of war, and civilians.59 More recently, Protocol I Additional to the GenevaConventions of 1949, signed in 1977, sought to protect civilians during international armed conflicts. Additional Protocol I emphasizes that "[i]n any armed conflict, the right of the Parties to the conflict to choose methods or means of warfare is not unlimited." 60 Additional Protocol II to the Conventions extends the protections stated in the Additional Protocol I to victims of non-international armed conflicts.61

It is easy to see how the principles of international humanitarian law apply to landmines. First, antipersonnel landmines needlessly aggravate human suffering, especially when they remain in the earth long after war has ended, continuing to kill civilians including children. Second, antipersonnel landmines are indiscriminate by definition: since they detonate automatically, they make no distinction between an enemy soldier, a soldier from the same army that laid the mine, a farmer, or a child. It has been pointed out elsewhere that the use of landmines may theoretically be discriminate, if they are directed against military objectives, but their effects become indiscriminate whenever they are left in the earth near civilians.62 This is so in the overwhelming majority of the countries that contain major minefields. Third and finally, many military experts argue that antipersonnel landmines are not militarily necessary, although this point is still the subject of debate.63

IV. Changes in State Practice and Opinio Juris Concerning Antipersonnel Landmines

The Ottawa Process and the Mine Ban Treaty have brought about a sudden, dramatic change in state practice regarding landmines, and an even more rapid change in opinio juris. 64As the British journalist John Ryle described it: “It’s the first time that a weapon in common use has been withdrawn from the arsenal. It’s also the first timethat the manufacture, possession, transfer, and use of an armament have been banned in a single, unambiguous piece of legislation. The relentless pressure of the campaigners has kept the treaty free of loopholes.”65 The fact that forty states ratified the treaty in only nine months demonstrates the power of anti-landmine governments, non-governmental organizations (NGOs), and international agencies to bring about change in worldwide state practice.66 Especially within “the glacial world of arms control,”67 the speed of the process has been striking. It reflects both the pressing nature of the landmines problem and emerging international consensus on the issue.68 The United Nations has referred to the Mine Ban Treaty as a “convention of conscience, that acquired force of binding international law with historic speed.” The remaining challenge is to universalize the Treaty.69

As noted above, a treaty can form the basis for a customary norm of international law. For two reasons, this is especially likely to happen in the case of the Mine Ban Treaty. First, the Mine Ban Treaty has already been embraced by most of the international community, in opinio juris if not yet in practice. Second, some states have already eliminated landmines from their arsenals. As discussed above, even treaties that are regularly violated, like the Convention Against Torture, can serve as the basis for customary international law. In the case of the Mine Ban Treaty, as in the case of the torture convention, even non-party states have expressed support for the ban.

The Mine Ban Treaty also strikes at the heart of states’ security concerns, banning a weapon that many states have long regarded as central to their capacity to defend themselves. In many states, powerful national security or defense establishments feared that the treaty would impinge on their authority. This has made it a difficult treaty for many countries to sign, not merely an easy, symbolic gesture in hypothetical support of human rights. Yet more than 80 percent of the world’s nations have signed the Treaty70 and 67 countries have ratified it, reflecting states’ willingness to make significant concessions to the Treaty’s purpose of ridding the world of landmines. This tide of opinio juris demonstrates the unusual strength of the rapidly-emerging norm against antipersonnel landmines.

V. Conclusion: Development of a Customary International Norm that Will Bind All States

In sum, we contend that a comprehensive ban on landmines is rapidly emerging as a customary norm of international law. Activists and sympathetic governments should realize that in working to persuade more countries to sign and ratify the Mine Ban Treaty and to stop using landmines, they are simultaneously working to establish customary international law. The two processes are parallel.

A powerful argument can be made that customary international law will have crystallized on the issue when China, Russia, and the United States, the three remaining major users of landmines, subscribe to the ban against them, or, at least, when those states cease to defend their use of the weapons. As discussed above, there is no minimum length of time that need elapse first, and we believe no state will be able to claim persistent objector status.

Of course, the only way to verify that custom has crystallized is to submit the question to an international court, as in the North Sea Continental Shelf , Nuclear Weapons and Nicaragua cases discussed above.71 We have explained how one might eventually argue that customary law has crystallized on the antipersonnel landmines ban. In the not-distant future, landmine activists might consider submitting the matter to the International Court of Justice.

1 Anthony A. D’Amato, The Concept of Custom in International Law, p. 4 (1971).

2 Malcolm N. Shaw, International Law, 2nd edition (1986) p. 59, citing Unger, Law in Modern Society (1976). For further discussion of the meaning of custom and its importance in international law see Oppenheim’s International Law, 9th edition (1992), p. 25, citing Gianni, La coutume en droit international (1931), Thirlway, International Customary Law and Codification (1972) et al.

3 Vienna Convention on the Law of Treaties, opened for signature May 23, 1969, UNTS Regis. No. 18,232, UN Doc. A/CONF.39/27 (1969) reprinted at 8 ILM 679 (1969); North Sea Continental Shelf Cases (FRG/Den.: FRG/Neth.), 1969 ICJ Rep. 3, 198, paragraph 71, (describing the way in which customary law would emerge from a treaty provision “which, while only conventional or contractual in its origin, has since passed into the general corpus of international law, and is now accepted as such by the opinio juris, so as to have become binding even for countries which have never, and do not, become parties to the Convention.”).

4 Shaw, supra note 2, p. 79, (stating “where treaties reflect customary law then non-parties are bound, not because it is a treaty provision but because it reaffirms a rule or rules of customary international law.”). The only states not bound by a customary norm are those that systematically oppose it, known as ‘persistent objectors.’ This is discussed in Section II(C).

5 Convention on the Prohibition of the Use, Stockpiling, Production and Transfer of Antipersonnel Landmines and On Their Destruction. Henceforth, ‘Mine Ban Treaty’ or ‘the treaty.’ Note that there is no legal distinction between ‘convention’ and ‘treaty.’ A treaty is defined in the Vienna Convention on the Law of Treaties as “an international agreement concluded between states in written form and governed by international law, whether embodied in a single instrument or two or more related instruments and whatever its particular designation.” Supra note 3, Art. 2(1)(a).

6 We use the word ‘norm’ in its legal sense, so that ‘customary norm’ is synonymous with ‘customary law.’

7 When the treaty entered into force on March 1, 1999, 134 governments had signed it and 65 had ratified it. See http://www.hrw.org/campaigns/mines/1999/icbl.

8 D’Amato, supra note 1, p. 104.

9 Jonathan I. Charney, The Persistent Objector Rule and the Development of Customary International Law, 56 Brit. Y.B. Int’l L. 1, 2. (1985).

10 See Vienna Convention on the Law of Treaties, supra note 3, Article 38 (“Nothing in articles 34 to 37 precludes a rule set forth in a treaty from becoming binding upon a third State as a customary rule of international law”); see also Ted L. Stein, The Approach of the Different Drummer: The Principle of the Persistent Objector in International Law, 26 Harv. Int’l L.J. 457, 458 (1985).

11 Supra note 5, Art.6, describing technical cooperation, and Art. 13, on amendments.

12 Oppenheim’s International Law, 9th edition (1992), p. 27.

13 See, e.g., The North Sea Continental Shelf Cases, supra note 3, paragraph 77 (describing the belief requirement: “The States concerned must therefore feel that they are conforming to what amounts to a legal obligation. The frequency, or even habitual character of the acts is not enough.”).

14 See, e.g. Harold Hongju Koh, Is International Law Really State Law? 111 Harv. L. Rev. 1824 (1998); but see Curtis A. Bradley & Jack L. Goldsmith, Federal Courts and the Incorporation of International Law, 111 Harv. L. Rev. 2260 (1998); Curtis A. Bradley & Jack L. Goldsmith, Customary International Law as Federal Common Law: A Critique of the Modern Position, 110 Harv. L. Rev. 815 (1997).

15 Supra, note 7.

16 Statute of the International Court of Justice, art. 38(1), annexed to the U.N. Charter.

17 See, e.g., Rudolf Bernhardt, Customary International Law, in: R. Bernhardt (ed), Encyclopedia of Public International Law, Volume I (1992), p. 901; D’Amato, supra note 1; Mark W. Janis, An Introduction to International Law p. 41-54 (1993).

18 Ian Brownlie, Principles of Public International Law, p. 5 (1990).

19 Shaw, supra note 2, p. 62, citing Gény, Méthode d’interprétation et sources en droit privé positif (1899).

20 The “Lotus” Case, 1927 P.C.I.J. , Series A, No. 10, 1927, p. 28.

21 North Sea Continental Shelf Cases, supra note 3, paragraph 77.

22 Case Concerning Military and Paramilitary Activities In and Against Nicaragua (Nicar. v. U.S.), 1986 I.C.J. 14 (Merits Judgment, June 27), (1986), paragraph 205, quoting The North Sea Continental Shelf Cases, I.C.J. Reports 1969, paragraph 77.

23 Id, paragraphs 188, 191.

24 American Law Institute, Restatement (Third) of the Foreign Relations Law of the United States (1987) Reporter’s Notes to § 102.

25 Oscar Schachter, International Law in Theory and Practice, p. 9 (1991).

26 Supra note 3, paragraph 73.

27 Mark E. Villiger, Customary International Law and Treaties p. 28, paragraph 75 (1985) citing Res 1721 A(XVI) of 20 December 1961, and Res 1962 XVIII of 13 Decembr 1963 containing the Declaration of Legal Principles Governing the Activities of States in the Exploration and Use of Outer Space. Villiger notes other scholars’ claims for instant custom, but is skeptical of that notion himself.

28 Brownlie, supra note 18, p. 5.

29 Shaw, supra note 2, p. 63.

30 Brownlie, supra note 18; Stein, supra note 10, p. 458 (stating that “this standard does not require universal participation, nor the participation of the state to which the rule is applied.”)

31 Supra note 22, paragraph 186.

32 Supra note 3, paragraphs 73, 74.

33 Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons, 1996 I.C.J. 226 (July 8), reprinted in 35 I.L.M. 809 (1996).

34 R.R. Baxter, Multilateral Treaties as Evidence of Customary International Law, 41 Brit. Y.B. Int’l L. 275, 300 (1965-66).

35 Supra note 22, p. 109, paragraph 207.

36 Id.

37 Prosecutor v. Tadic, Decision on the Defense Motion for Interlocutory Appeal on Jurisdiction, Case No. IT-94-AR72 (1995), p. 48-74, paragraphs 86-145.

38 Theodor Meron, The Continuing Role of Custom in the Formation of International Humanitarian Law, 90 Am. J. Int’l L. 238, 240 (1996).

39 Louis Sohn, The New International Law: Protection of the Rights of Individuals Rather than States, 32 Am. U. L. Rev. 1, 16 (1982).

40 American Law Institute, Restatement (Third) The Foreign Relations Law of the United States § 702 (1987).

41 See the Convention Against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, 39 U.N. GAOR Supp. (No. 51) 197, U.N. Doc. A/39/51 (1984). It is interesting to compare this treaty with the Landmine Ban Treaty. In both cases, NGOs helped to develop public consensus in many countries, perhaps contributing to the unusually rapid development of opinio juris and customary law.

42 Stein, supra note 10, p. 465.

43 Charney, supra note 9, p. 2.

44 Stein, supra note 10, p. 458.

45 Id. (emphasis added); see also Charney, supra note 9, p. 2 (noting that “virtually all authorities maintain that a State which objects to an evolving rule of general customary international law can be exempted from its obligations”).

46 Stein, supra note 10, p. 459.

47 But see Charney, supra note 9, p. 24 (concluding that the “persistent objector rule is, at best, only of temporary or strategic value in the evolution of rules….).The “persistent objector” principle, moreover, may itself admit of exception for certain jus cogens norms, peremptory rules of international law from which no derogation is permitted (e.g., the prohibition against genocide.) The threshold of state practice and opinio juris needed to establish that some customary international law rule is jus cogens, however, remains extremely high; at present, customary international law concerning landmines almost certainly fails to rise to this level.

48 Id.

49 G.A. Res. 51/45S, U.N. GAOR, 51ST Sess., U.N. Doc. A/RES/51/45/Add.11 (1997).

50 Howard Williams, 125 Nations Line up to Sign Treaty Banning Anti-Human Landmines, Agence France-Presse, Dec. 3, 1997.

51 Human Rights Watch, North African Countries Urged to Ban Landmines (visited Jan. 28, 1999) <http://www.hrw.org/press/1999/jan/naf0125>.

52 Vienna Convention on the Law of Treaties, supra note 10, Art. 38.

53 See, e.g. Baxter, supra note 33, p. 294.

54 11 Trials of War Criminals Before the Nuernberg Military Tribunals Under Control Council Law No. 10, p. 462 (1948). Also see Theodor Meron, The Geneva Conventions as Customary Law, 81 Am. J. Intl. L., p. 359 (1987).

55 Antonio Cassese, The Geneva Protocols of 1977 on the Humanitarian Law of Armed Conflict and Customary International Law, 3:55 Pacific Basin L.J. 1984; Meron, Id.

56 Memorandum for the United States as Amicus Curiae, Filartiga v. Peña-Irala, 630 F.2nd 876 (2nd Cir. 1980) (No. 79-6090), reprinted in 19 I.L.M. 585 (1980).

57 The Declaration of St. Petersburg, signed on 29 November, 1868, 1 A.J.I.L. (Supp.) 95-96 (1907).

58 See, e.g. Treaty (II) with Respect to the Laws and Customs of War on Land (“Hague II”), Article 239(e), prohibiting the use of “arms, projectiles or material of a nature to cause superfluous injury” and the Treaty (IV) Respecting the Laws and Customs of War on Land (“Hague IV”).

59 Convention for the Amelioration of the Condition of the Wounded and Sick in Armed Forces in the Field (Geneva Convention No. I) Aug. 12, 1949, 75 UNTS 31; Convention for the Amelioration of the Condition of the Wounded, Sick and Shipwrecked Members of the Armed Forces at Sea (GenevaConvention No. II), Aug. 12, 1949, 75 UNTS 85; Geneva Convention Relative to the Treatment of Prisoners of War (Geneva Convention No. III), Aug. 12, 1949,75 UNTS 135;Convention Relative to the Protection of Civilian Persons in Time of War (Geneva Convention No. IV), Aug. 12, 1949, 75 UNTS 287.

60 Protocol Additional to the Geneva Treatys of 12 August 1949, Relating to the Protection of Victims of International Armed Conflicts (Protocol I), Aug. 15, 1977, 1125 U.N.T.S. 3, 3608, 16 I.L.M. 1391, 1391442

61 Protocol Additional to the Geneva Treatys of 12 August 1949, Relating to the Protection of Victims of NonInternational Armed Conflicts (Protocol II), Aug. 15, 1977, 1125 U.N.T.S. 609, 609699, 16 I.L.M. 1443, 1443449.

62 Landmines: A Deadly Legacy, The Arms Project, Human Rights Watch, and Physicians for Human Rights, 275.

63 See, e.g. Antipersonnel Landmines: Friend or Foe? A Study of the Military Use and Effectiveness of Antipersonnel Mines. International Committee of the Red Cross, 1996.

64 This section was prepared using secondary sources, before the final versions of the Landmine Monitor reports were available. The reports are authoritative for any data on state practice.

65 See John Ryle, City of Words, The Guardian, Dec. 8, 1997, at 5.

66 Office of the Secretary General, UN Press Briefings, Press Conference Marking the Fortieth Ratification of Landmines Convention Triggering March 1999 Entry into Force, http://1www.un.org//.

67 John Ryle, The Landmines Ban and its Discontents, New York Review of Books, Nov. 5, 1998, p. 61.

68 Id.

69 UN Press Briefing, Press Conference on Antipersonnel Mine Convention, Oct. 1, 1998 http://1www.un.org//.

70 See China, Russia, US ‘feeling the heat’ for not signing landmine pact,” Agence France-Presse, Dec. 2, 1998.

71 Such a case need not be filed by one state against another. The International Court of Justice also issues advisory opinions, like the Nuclear Weapons one.