North Sea Continental Shelf Cases (Federal Republic of Germany / Denmark; Federal Republic of Germany / Netherlands) (1969)

It is two cases in one, and the examiner may want either.

1. Sources. The most detailed judicial account of how a treaty rule may or may not pass into customary international law, and the sharpest statement of the opinio juris requirement.
2. Law of the sea. The rejection of equidistance as a rule of law, the doctrine of natural prolongation, and the substitution of delimitation by agreement in accordance with equitable principles, which is now the standard in Articles 74 and 83 of the 1982 Convention.

Germany's North Sea coast is markedly concave. Denmark and the Netherlands lie on either side. Applying the equidistance method to lateral boundaries between adjacent States would have cut Germany off from the central North Sea, because the slightest irregularity of coastline is magnified the further out the line runs. Denmark and the Netherlands were parties to the 1958 Geneva Convention; Germany had signed but not ratified it, so Article 6 did not bind her as treaty law. Negotiations in 1965 and 1966 failed, the two States insisting on equidistance and Germany unable to accept its result.

1. Was Germany bound by Article 6 of the 1958 Convention otherwise than as a party?
2. Had the equidistance principle become a rule of customary international law?
3. What principles and rules govern the delimitation?

Germany was not bound by equidistance. Equidistance was neither declaratory of nor constitutive of customary law, and State practice had not made it so. Delimitation must be effected by agreement in accordance with equitable principles, taking account of all relevant circumstances, so as to leave to each party as much as possible of the natural prolongation of its land territory without encroaching on that of the other.

The passage of a treaty rule into custom is possible but not light. A conventional rule may generate a rule which has "since passed into the general corpus of international law, and is now accepted as such by the" general opinion of States, binding even on non-parties. "There is no doubt that this process is a perfectly possible one and does from time to time occur; it constitutes indeed one of the recognized methods by which new rules of customary international law may be formed. At the same time this result is not lightly to be regarded as having been attained."

Condition one: a norm-creating character. "It would in the first place be necessary that the provision concerned should, at all events potentially, be of a fundamentally norm creating character such as could be regarded as forming the basis of a general rule of law." In the abstract equidistance might qualify, but Article 6 did not, for three reasons.

• Article 6 puts the obligation to use equidistance second, after a primary obligation to delimit by agreement. "Such a primary obligation constitutes an unusual preface to what is claimed to be a potential general rule of law."
• The role of the notion of special circumstances, and "the very considerable, still unresolved controversies as to the exact meaning and scope of this notion", raise further doubts about its norm-creating character.
• Reservations were permitted to Article 6, unlike to Articles 1 and 2. So long as that faculty exists, it is the Convention itself which seems to deny to Article 6 the same norm-creating character.

Condition two: participation. "it might be 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." Here the number of ratifications and accessions, though respectable, was hardly sufficient. The Court added a point of method: that non-ratification may sometimes be due to factors other than disapproval "can hardly constitute a basis on which positive acceptance of its principles can be implied: the reasons are speculative, but the facts remain."

Condition three: practice and the passage of time. "Although the passage of only a short period of time is not necessarily, or of itself, a bar to the formation of a new rule of customary international law on the basis of what was originally a purely conventional rule, an indispensable requirement would be that within the period in question, short though it might be, State practice, including that of States whose interests are specially affected, should have been both extensive and virtually uniform in the sense of the provision invoked; - and should moreover have occurred in such a way as to show a general recognition that a rule of law or legal obligation is involved."

Why the practice failed. About fifteen delimitations by equidistance were cited. Over half the States concerned were or became parties to the Convention, so their acts were presumably in application of it, and no inference about custom could legitimately be drawn. As for non-parties, "the basis of their action can only be problematical and must remain entirely speculative"; there is no shred of evidence that they believed themselves to be applying a mandatory rule. And almost all the cited delimitations were median lines between opposite States, not lateral boundaries between adjacent States, so they were not precedents for the present problem.

The statement of opinio juris. This is the most quoted formulation in the law of sources: "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 need for such a belief, i.e., the existence of a subjective element, is implicit in the very notion of the" opinio juris sive necessitatis. "The States concerned must therefore feel that they are conforming to what amounts to a legal obligation."

And the warning against counting acts: "The frequency, or even habitua1 character of the acts is not in itself enough. There are many international acts, e.g., in the field of ceremonial and protocol, which are performed almost invariably, but which are motivated only by considerations of courtesy, convenience or tradition, and not by any sense of legal duty."

The Court then applied the Lotus dictum: abstention proves nothing unless based on consciousness of a duty to abstain.

Conclusion on sources. "if the Geneva Convention was not in its origins or inception declaratory of a mandatory rule of customary international law enjoining the use of the equidistance principle for the delimitation of continental shelf areas between adjacent States, neither has its subsequent effect been constitutive of such a rule; and that State practice up-to-date has equally been insufficient for the purpose."

Why equidistance cannot be a rule. "the essential reason why the equidistance method is not to be regarded as a rule of law is that, if it were to be compulsorily applied in all situations, this would not be consonant with certain basic legal notions which, have from the beginning reflected the" opinio juris in the matter of delimitation, namely that delimitation must be the object of agreement and that the agreement must be arrived at in accordance with equitable principles.

The three rules. The Court set them out.

• The parties must enter into negotiations with a view to arriving at an agreement, "and not merely to go through a forma1 process of negotiation as a sort of prior condition for the automatic application of a certain method of delimitation in the absence of agreement"; they must conduct themselves so that the negotiations are meaningful, "which will not be the case when either of them insists upon its own position without contemplating any modification of it".
• The parties must act so that, taking all the circumstances into account, equitable principles are applied; equidistance may be used for this purpose, but other methods exist and may be employed alone or in combination.
• "the continental shelf of any State must be the natural prolongation of its land territory and must not encroach upon what is the natural prolongation of the territory of another State."

Equity is not ex aequo et bono. "in this field it is precisely a rule of law that calls for the application of equitable principles. There is consequently no question in this case of any decision ex aequo et bono, such as would only be possible under the conditions prescribed by Article 38, paragraph 2, of the Court's Statute." Applying equitable principles is applying law; deciding ex aequo et bono requires the parties' consent and frees the Court from the law.

Why equidistance produces inequity. Two reasons. First, "The slightest irregularity in a coastline is automatically magnified by the equidistance line as regards the consequences for the delimitation of the continental shelf", so that with concave or convex coastlines the greater the irregularity and the further from the coast, the more unreasonable the result; such exaggeration of a natural feature "must be remedied or compensated for as far as possible, being of itself creative of inequity." Second, in a sea like the North Sea with no outer shelf boundary the claims of several States converge, meet and intercross far from the coast.

Overlaps. Where the methods chosen lead to overlapping areas, the situation "must be accepted as a given fact and resolved either by an agreed, or failing that by an equal division of the overlapping areas, or by agreements for joint exploitation, the latter solution appearing particularly appropriate when it is a question of preserving the unity of a deposit."

The factors for negotiation. The general configuration of the coasts and any special or unusual features; so far as known or readily ascertained, the physical and geological structure and natural resources of the shelf areas involved; and "The element of a reasonable degree of proportionality", which a delimitation carried out in accordance with equitable principles ought to bring about between shelf areas and the length of coast measured in the general direction of the coastline, account being taken of other shelf delimitations in the same region.

• The three conditions for a treaty rule to become custom are the examinable core: norm-creating character, widespread and representative participation including specially affected States, and extensive and virtually uniform practice showing recognition of legal obligation.
• The opinio juris passage and the ceremonial-and-protocol example are the two quotations to have by heart.
• On delimitation, the modern rule is in Articles 74 and 83 of the 1982 Convention, which require agreement on the basis of international law as referred to in Article 38 of the ICJ Statute, in order to achieve an equitable solution. That formula is this judgment, codified.
• A caution about the printed dispositif: the delimitation rule is delimitation by agreement in accordance with equitable principles. Some reproductions of the operative paragraph carry a typographical slip for equidistance; the judgment's whole reasoning forbids that reading.