1 Dispute Regarding Navigational and Related Rights (Costa Rica v. Nicar.) (Int’l Ct. Justice July 13, 2009). The basic documents, decisions, pleadings, transcripts, press releases, and other materials for this case and others are available on the Court’s Web site, http://www.icj–cij.org.

2 Provisions of the 1858 Treaty were the subject of two arbitration awards: the March 22, 1888, arbitral award made by the president of the United States and the September 30, 1916, decision of the Central American Court of Justice. The Court, however, found that neither award settled the questions at issue in this case (para. 49). It may be noted that in the instant case, Costa Rica urged the Court also to consider “the rules of general international law that are applicable . . . to navigation on ‘international rivers’” (para. 32). The Court found it unnecessary to take a position on whether “there exists, in customary international law, a regime applicable to navigation on ‘international rivers’ “or” whether the San Juan falls into the category of ‘international rivers’” (para. 34). Instead, “the 1858 Treaty of Limits completely defines the rules applicable to the section of the San Juan river that is in dispute in respect of navigation” (para. 36).

3 The authoritative Spanish version of Article VI is reproduced at paragraph 43.

4 Here the Court articulated the possibility of a contemporaneous intent to create an evolutionary meaning, meshing the two interpretive approaches. Judge ad hoc Guillaume expanded on the Court’s past practice of l’interprétation “contemporaine”Versus l’interprétation “évolutive” m his declaration (see paras. 8–16) appended to the judgment, ultimately agreeing with the Court’s interpretation of the term comercio, but for different reasons.

5 For a critique of the Court’s interpretation of the term comercio in this case, see Milanovic, Marko The ICJ and Evolutionary Treaty Interpretation., EJIL Talk! (July 14, 2009), at http://www.ejiltalk.org/author/guestcontributor/page/3/ Google Scholar.

6 All navigation outside the scope of Costa Rica’s right of navigation as provided for in the 1858 Treaty is subject to Nicaragua’s “complete power of regulation” (para. 85).

7 [Author’s note: In subsequent paragraphs the Court added environmental protection to the list of legitimate purposes (see paras. 88–89).]

8 Considered in paragraphs 103–07, this category was found to be not unreasonable (see para. 106).

9 Considered in paragraphs 108–10, this category was found to be for legitimate purposes, with the regulations imposing no significant impediment to Costa Rica’s navigational rights (see para. 109)

10 Considered in paragraphs 125–29, this category of regulation was not proven by Costa Rica to be unreasonable (see para. 128).

11 Considered in paragraphs 130–32, this regulation did not impose an impediment to navigation (see para. 132).

12 Email communications between author and coordinator of the International River Boundaries Database, John W. Donaldson, Senior Research Associate, International Boundaries Research Unit, Durham University, Durham, UK (Jan. 11 & Feb. 2, 2010).

13 Judge ad hoc Guillaume argued that no such customary international law regime exists (see Declaration, para. 3).

14 Judge ad hoc Guillaume characterized this minimal right of navigation as a matter of custom, not treaty, albeit custom deduced in the teeth of treaty language to the contrary: “Elle semble avoir renoncé à fonder cette solution sur une coutume contra legem qui au surplus n’est pas établie” (Declaration, para. 19).

15 The Court spoke to this issue in its consideration of Nicaragua’s visa requirement:

Under Article VI of the Treaty the titleholder of the right of free navigation is Costa Rica. Owners and operators of Costa Rican vessels benefit from that right when navigating on the San Juan river for commercial purposes. Passengers on vessels exercising Costa Rica’s right of free navigation also benefit from that right, even if such passengers are not Costa Rican nationals. (Para. 114)

16 “The Court accordingly concludes that Costa Rica has a customary right” (para. 141, emphasis added).

17 “Accordingly, the Court concludes that fishing by the inhabitants of the Costa Rican bank of the San Juan river for subsistence purposes from that bank is to be respected by Nicaragua as a customary right” (para. 144).

18 Costa Rica does not appear to have made any claim of state practice, and it is difficult to conceive of the practice of subsistence fishing by a small number of individuals in a remote border area as being anything other than private in nature and without the imprimatur of government.

19 Elsewhere, this kind of right has been called a “traditional right.” See, e.g., Gov’t of Sudan v. Sudan Peoples’ Liberation Movement/Army (“Abyei Arbitration”), paras. 748–66 (Arb. Trib. July 22, 2009) (reported by Coalter G. Lathrop at 104 AJIL 66 (2010)); Eritrea v. Yemen, Second Stage, Maritime Delimitation, 22 R.I.A.A. 335, para. 108 (Perm. Ct. Arb. Dec. 17, 1999), reprinted in 40 ILM 983 (reported by W. Michael Reisman at 94 AJIL 721 (2000)).

20 In his separate opinion (para. 20), Judge Sepúlveda–Amor criticized the Court’s reasoning in respect of subsistence fishing for deviating from its “previous findings on the recognition of rules of customary international law.” Although the word “customary” is used in the decision, there is no indication that the Court sought to find a rule of customary international law in the global sense: the Court did not purport to have found universal state practice, much less opinio juris, to support such a rule, and did not indicate that the effect of any such rule would extend beyond the parties to this case. Sepúlveda–Amor provided an alternative legal theory to support the Court’s finding here: “namely the principle of acquired or vested rights” (Sep. Op., para. 28). This alternative basis for the Court’s finding on subsistence fishing is much more persuasive than, and in no apparent conflict with, the Court’s own reasoning.

21 See Sep. Op., Sepúlveda–Amor, J., paras 28–30 (quoting Certain German Interests in Polish Upper Silesia (1926); Land, Island and Maritime Frontier Dispute (1992); and Land and Maritime Boundary Between Cameroon and Nigeria (2002)); see also Gov’t of Sudan v. Sudan Peoples’ Liberation Movement/Army (“Abyei Arbitration”), para. 753 (“The jurisprudence of international courts and tribunals as well as international treaty practice lend additional support to the principle that, in the absence of an explicit prohibition to the contrary, the transfer of sovereignty in the context of boundary delimitation should not be construed to extinguish traditional rights to the use of land (or maritime resources).”).