Luigi Crema è assegnista di ricerca in diritto internazionale, Università degli Studi di Milano

During these first months of 2014 the ICJ has already issued two decisions: recently, and receiving much public attention, in Whaling in the Antarctic (Australia v. Japan); and in January, creating less ripples  in the community of international lawyers, on the delimitation of the sea between Peru and Chile (Maritime Dispute, Peru v. Chile). Both disputes raise many interesting points, although on very different topics. The former deals with the alleged illegality of the conduct of a state according to a multilateral treaty. The latter involves the maritime delimitation between two states decided by the Court, in part by inferring a tacit agreement not even mentioned by the parties in their pleadings, and in part by drawing an equidistant line. The decisions offer many interesting features for consideration. Here, we will focus on what both decisions have in common: that they discuss the interpretation of an agreement, explicit or tacit, and the role played (or not played) by the intention of the parties and their subsequent practice.

The facts of the Whaling case are known to the readers of this blog, as Chiara Ragni has already given a complete account over them. The heart of the dispute was the interpretation of Article VIII of the International Convention for the Regulation of Whaling (ICRW or Whaling Convention), regulating the use of whales for purposes of scientific research (see para. 51 of the judgment). Australia pointed to several resolutions passed by the International Whaling Commission (IWC or Commission) to interpret this provision that would exclude the possibility of making recourse to lethal methods, notwithstanding Art. VIII explicitly encompasses this possibility. The Commission is an organ created by the Whaling Convention composed of all the states parties. According to the Whaling Convention Art. VI, the Commission has the power to “make recommendations to any or all Contracting Governments on any matters which relate to whales or whaling and to the objectives and purposes of this Convention” (cf. Art. VI and paras 46, 51 and 79 ff.). It also has the more fundamental power to issue guidelines and modify the obligations deriving from the treaty itself through amendment to the Schedule (an instrument regulating the effective functioning of the Convention, cf. Arts I, III, and V of the ICRW, and paras 44 and 45 of the judgment). According to Australia, several resolutions adopted in the past by the Commission imply an dynamic interpretation of Art. VIII (paras 78-79). However, the Court rejected the Australian argument with a textual interpretation of Art. 31.3 of the Vienna Convention on the Law of Treaties of 1969 (VCLT):

“[M]any IWC resolutions were adopted without the support of all States parties to the Convention and, in particular, without the concurrence of Japan. Thus, such instruments cannot be regarded as subsequent agreement to an interpretation of Article VIII, nor as subsequent practice establishing an agreement of the parties regarding the interpretation of the treaty within the meaning of subparagraphs (a) and (b) …” (Whaling in the Antarctic, para. 83).

By refusing to consider a body of resolutions passed by a Commission in which all the members are represented, the Court shows itself to be attentive to the intention of all the parties, as expressed in the text, declining to adopt any creative interpretation. The Court, in fact, does not give any interpretive weight to these resolutions because of some evident diversity of opinion among the members. The same approach can also  be found in the individual opinion of Judge Christopher Greenwood, which describes the practice of Art. 31.3.b) as requiring the simultaneous fulfilment of three conditions: that the practice come from the parties, in the application of the interpreted treaty, and that it show agreement among them. He says:

“Where a treaty creates a body such as the International Whaling Commission in which all the member States are represented, resolutions adopted by that body form part of the subsequent practice of the parties to the treaty. As such, they are capable of constituting an aid to the interpretation of the treaty, in accordance with the principle set out in Article 31 (3) (b) of the 1969 Vienna Convention on the Law of Treaties. However, subsequent practice is valuable as an aid to the interpretation of a treaty only to the extent that it establishes the agreement of the parties. … Far from establishing the agreement of the parties to the Convention, these resolutions demonstrate the absence of any agreement and cannot, therefore, be relied on to sustain an interpretation of the Convention which can bind Japan” (Greenwood, Separate Opinion, para. 6).

Greenwood goes on, stressing that the nature of the Whaling Convention as a living instrument does not allow for shortcutting the procedures in place to amend it, given the clear rules establishing the amendment and evolution of the Convention (ivi, para. 7). While this conclusion is correct, the quoted premise he expresses seems overly categorical. The Court and Greenwood are very clear in interpreting the content of Art. 31.3.a) and b), but they do not consider whether the recommendations of the Commission, or the subsequent practice of the parties in general, may have interpretive relevance outside Art. 31.3.b) of the VCLT.

In previous decisions the ICJ did not limit itself to considering subsequent practice in light of Art. 31.3.b), but also as an additional interpretive element, under Art. 32 (Kasikili/Sedudu Island (Botswana/Namibia), 1999, para. 80; Sovereignty over Pulau Ligitan and Pulau Sipadan (Indonesia/Malaysia), para. 80; Legality of the Use by a State of Nuclear Weapons in Armed Conflict, para. 27; Pulp Mills on the River Uruguay (Argentina v. Uruguay), Order on Provisional Measures, 2006, para. 53), or to clarify the object and purpose of a treaty or its interpretation as a whole (Oil Platforms (Iran v. United States), Preliminary Objection, paras 29–30; Constitution of the Maritime Safety Committee of the IMCO, 1960, pp. 167-169). These further possibilities, although not expressed in the Court’s decision, emerge not only in previous ICJ decisions, but also in several individual opinions of the Whaling case. For example, Judge ad-hoc Hilary Charlesworth raises this point in regard to the role of the resolution in determining the extent of the “duty to cooperate” deriving from the ICRW:

“Since the moratorium on commercial whaling came into effect in the 1985/1986 pelagic and 1986 coastal seasons, most IWC resolutions on special permit whaling have attracted a number of negative votes, which precludes them as evidence of the parties’ agreement on the ICRW’s interpretation. However, there remain some significant resolutions that were adopted by consensus and thus must inform the interpretative task. I note that resolutions adopted by a vote of the IWC have some consequence although they do not come within the terms of Article 31.3 of the Vienna Convention. Particularly when they are adopted by a large majority of IWC members, the resolutions are relevant to the duty of co-operation, discussed below” (Charlesworth, Separate Opinion, para. 4).

Another interesting observation on the possible role of the practice of the parties, even when not all the conditions set by Art. 31.3.b) are met, is described by Judge Hanqin Xue. Without referring to Art. 31 or 32 of the VCLT, she notes the importance of subsequent practice in balancing the weight of the two purposes of the convention (“sustainable exploitation of whales” and “their conservation”, as indicated by the ICJ itself at para. 55 of the decision):

“In the course of its 68 years’ operation since 1946, the Convention, as an evolving instrument, has undergone considerable change by way of its Schedule amendments. Although terms on scientific whaling under Article VIII remain intact, various restrictions on commercial whaling for purposes of conservation have indeed exerted a creeping effect on the way in which scientific research may be conducted, particularly with respect to methodology and scale of sample size. Notwithstanding policy differences between the anti-whaling group and the whaling parties, the parties have generally recognized the importance of conservation for the protection of whale resources” (Xue Separate Opinion, para. 12).

In short, it seems overly simplistic, and out of line with previous ICJ decisions, to use the specific dynamic described by Art. 31.3.b) as a strict limitation on the potential interpretive aid offered by subsequent practice (in this case, resolutions adopted by a body in which all the member states of a treaty are represented).

The dispute in the Peru v. Chile case is very different, as is the approach taken by the Court in that case. It does not deal with a multilateral treaty but rather with declarations and agreements (explicit and tacit) between the two countries, and between them and Ecuador. These agreements regulate specific situations concerning the Pacific Ocean, its protection, and its exploitation, and they do not establish any supervisory body. However, in this case too, as in the previous one, the Court faced a problem of interpretation and ascertainment of the intention of the parties, in particular of the 1952 Santiago Declaration (that, notwithstanding the name, is a treaty, cf. para. 48 of the Judgment), of several agreements of 1954, and of a tacit agreement emerged in between the two. The Court sought to clarify three questions: whether the parties to these agreements intended to establish a lateral limit to their respective portions of Ocean, the method they adopted to establish it, and the length of the delimitation line from the coast (whether 200 miles or less).

In its decision, the Court first interprets the 1952 Santiago Declaration with a careful analysis, using the Vienna Convention of 1969: it considers the text, in light of the object and purpose, the immediate context and the travaux préparatoires (para. 57 ff.). The Court does not consider other events subsequent to that stipulation – at least to interpret the 1952 Declaration –, does not mention Art. 31.3.b) and subsequent practice, and concludes that the parties did not intend to delimit their respective portions of Ocean. The Court then, from the use of the present tense in a treaty of 1954 (paras 81, 90-91), infers the existence of a tacit agreement between the two parties, cemented by some subsequent events, in particular the arrangements on lighthouses (paras 96-99) and the fishing activities conducted by private entities (paras 103-111). Here, the Court is not interpreting a text, and, therefore, does not invoke the Vienna Convention and Art. 31.3.b). Rather, it investigates the content of the tacit agreement: the subsequent practice of the parties and of private entities such as fishermen is considered as evidence of the content of the agreement. However, their dynamic is similar: subsequent practice is, in both cases, used to interpret a treaty and to ascertain the intention of the parties. In fact, two dissenting opinions refer to all these subsequent agreements and practices to interpret, in a convincing way, the 1952 Declaration (Joint Dissenting Opinion of Judges Gaja, Xue, Bhandari, and Judge ad-hoc Orrego-Vicuña, paras 9-34, on contemporaneous and subsequent agreements and practice; Separate Opinion of  Judge ad-hoc Orrego-Vicuña, paras 20-29). The joint dissenting opinion concludes, at para. 35:

“The text of paragraph IV of the 1952 Santiago Declaration implies that the parallel that passes through the point where the land frontier reaches the sea represents the lateral boundary of the general maritime zones of the Parties, which, on the basis of the Parties’ maritime claims as pronounced in the Santiago Declaration, extends for 200 nautical miles. Some subsequent agreements concluded between the Parties confirm this interpretation of the Declaration, in particular the 1954 Agreement, the 1955 Protocol and the 1968 agreement. These instruments provide a solid legal basis for the existence of a maritime boundary that extends along the parallel for 200 nautical miles from the continental coasts of Peru and Chile.”

In the decision, the Court does not appear very consistent in its position toward the intention of the parties. It first takes a strict approach in interpreting the 1952 Santiago Declaration; notwithstanding a lack of clarity in the agreement, the Court does not venture beyond a narrow use of text, context, object and purpose, and preparatory works, and does not use subsequent practice to inform its interpretation of it. Then, the Court’s regard for the intention of the parties appears to diminish: it quite freely declares the existence of a tacit agreement, and the same practices that it might have used to interpret the Declaration of 1952 are then used to investigate the content of this agreement. However, the evidence cited by the Court in support of the existence of the tacit agreement seems to be neither conclusive nor strongly convincing; this weakness is stressed by several separate opinions (Declaration of President Tomka, paras 2 ff. and 25; Separate Opinion of Judge Owada, paras 5-6, and 12; Dissenting Opinion of Judge Sebutinde, paras 2 and 12). It seems more respectful of the intention of the parties to use subsequent practice and agreements in the interpretation of the 1952 Declaration, as highlighted by the joint dissenting opinion quoted above, rather than the path taken by the Court with its finding of the tacit agreement.

To sum up, what is new about intention of the parties, interpretation and subsequent practice after these two ICJ decisions? They deal with different situations, having in common the fact that the Court interprets agreements and considers the role of subsequent practice. In the Whaling case the Court is careful to adhere closely to the text of the treaty and the intention of the parties; it does refer to Art. 31.3.b), and in doing so seems to focus excessively on that provision, forgetting other potential interpretive roles of subsequent practice. The Maritime Delimitation does refer to subsequent practice to deduce the content of a tacit agreement, but it does not to interpret an agreement of 1952 although doing so may have been wise. In fact, its decision ignores a rich set of agreements and practice by the parties to interpret an explicit agreement, only to later rely on a thin set of practices to flesh out a tacit agreement whose existence does not seem very well demonstrated).

It thus seems that, while the ICJ is actively addressing the issue of subsequent practice, the members of the Court have not yet arrived at an organic, shared position on the roles of subsequent practice in interpreting treaties.