On Monday, the ICJ delivered its judgment in the Costa Rica v. Nicaragua case, concerning navigational and related rights on the river San Juan (Registry summary; judgment). The case itself is not terribly important in the grand scheme of things, but upon reading the judgment I came across several questions of broader import that our readers might find of interest.
But first just to say a bit about the facts of the case for the sake of greater comprehension. The river San Juan is on the border between Costa Rica and Nicaragua. The border, however, does not run along the thalweg of the river, as is usually the case with river borders, but is set by treaty to run along the Costa Rican coast. Thus, the entire river belongs to Nicaragua as sovereign. The question raised by the case is what are the navigational and related rights on the river of Costa Rica and its riparian communities, under the terms of the 1858 Treaty of Limits between Costa Rica and Nicaragua. The principal of these rights was set by Article VI of the Treaty, giving Costa Rica a perpetual right of free navigation ‘con objectos de commercio’.
There was a dispute between the parties as to the meaning of this last phrase, with Costa Rica claiming that it meant ‘for the purposes of commerce’, while Nicaragua maintained that it meant solely ‘with the articles of commerce’, i.e. with merchandise (para. 45). On this issue, the Court sided with Costa Rica (paras. 50-56), and the judgment is generally speaking more in its favor than in Nicaragua’s. The background to this dispute is at least partly one of economic self-interest: Costa Rica claimed that this phrase covered not merely trade in goods, but also trade in services, such as the transportation of tourists and passengers on the river by Costa Rican ships. Nicaragua, on the other hand, asserted that the phrase covered only the trade in goods.
This brings me to the issues of general import raised in the case. First, and most important, is the Court’s approach to treaty interpretation. In that regard the Court gave short shrift to its long-standing dicta that restrictions on state sovereignty are not to be presumed lightly (paras. 47-48), and it also made several fascinating remarks on evolutionary treaty interpretation, to which I will devote the bulk of this post.
Second, the Court was quite ‘activist’ in basically creating bright line rules out of whole cloth from treaty provisions that were silent on the concrete matter at hand, but which the Court considered to have exhaustively regulated the relations between the parties. For instance, the Court held that Nicaragua may not impose any visa requirements on passengers on Costa Rican ships on the river, though it could have held instead that Nicaragua may not unjustifiably deny visas to such passengers, but that it could do so in some exceptional circumstances. This willingness to set bright line rules probably emanated from the Court’s desire to preclude further disputes between the parties and definitively settle the matter.
Third, there is the Court’s willingness the establish, with very little evidence, the existence of a bilateral customary rule binding the parties. Namely, it found that the riparian communities in Costa Rica, through the Costa Rican state, had a customary right to subsistence fishing from the river. The Court derived such a customary right solely from the absence of protest by Nicaragua to fishing by Costa Ricans, without in any way searching for opinio juris by Nicaragua and Costa Rica that this absence of protest derived not from the lack of practical significance of the very small amount of fishing involved, but from Nicaragua’s sense of legal obligation, its view that the riparian Costa Ricans had a right to fish as they did.
Indeed, the Court found such a customary right even though Costa Rica never claimed, until the case came to the Court, that it had such a right in its relations with Nicaragua. The Court justified its position by saying that the paucity of evidence of custom is explained by the remoteness of the area and its small population (para. 141). Now, we all know that in some cases the Court does not apply the criteria for formation of custom in a very rigorous way (e.g. regarding the use of force in the 1986 Nicaragua case), while in others it is conversely extremely hostile to the existence of custom (e.g. in the Asylum or the North Sea Continental Shelf cases). But I don’t think that I’ve ever seen the Court establish a customary rule, even a bilateral one, in quite so off-hand a way as it did here. In that regard, I find the separate opinion of Judge Sepulveda to be more persuasive.
But now onto the juiciest part of the judgment, the Court’s approach to evolutionary treaty interpretation. (Warning and apologies in advance for any overly-theoretical rambling).