US-Mexico maritime treaty does not disprove necessity of UNCLOS for establishing legal claims, opponents of UNCLOS are conflating ECS delineation with maritime boundary delimitation

UNCLOS opponents habitually point to the 2000 US-Mexico maritime delimitation treaty, portraying it as an irrefutable example of why the United States does not need UNCLOS in order to exploit the resources within its ECS; therefore, the “legal certainty” offered by a CLCS ECS submission is not as vital as UNCLOS proponents would suggest.77 But this argument is flawed in that it relies on a paradigmatic conflation between two separate and distinct UNCLOS procedures: ECS delineation by a coastal State and maritime boundary delimitation between two or more States.⁷⁸ These two procedures are not the same thing, nor do they entail the same rights and privileges.

Article 76 was drafted with the intent of creating a universal mechanism in which the outer limits of a State's continental shelf would eventually be permanently fixed so as to exclude any future expansion of national jurisdiction into the international seabed area.⁷⁹ Article 76(10) expressly provides that the provisions of article 76 are “without prejudice” to the question of continental shelf delimitation between States with opposite or adjacent coasts.⁸⁰ Specifically, article 76(10) guarantees that a submission of an ECS claim by one State will not affect the rights of another State where the delimitation of their shared continental shelf remains at issue.⁸¹ Standing alone, this may not be dispositive of much, but consider for a moment that out of the twentynine areas in which continental shelves exist beyond 200 nautical miles, only seven of those areas involve jurisdictional claims exercised by a single State.82 In other words, the drafters of article 76 were aware of the potential for conflict between States with competing maritime claims and, thus, included the “without prejudice” language so as to encourage greater treaty accession.⁸³ Consequently, article 76(8) and (9)—concerning the final and binding nature of a delineated ECS- are thus rendered without legal effect if relied upon in a delimitation dispute where an overlapping ECS becomes a point of contention between two coastal States.⁸⁴ In fact, the entire ECS framework outlined in article 76 becomes essentially moot within the context of an ongoing delimitation dispute between two coastal States.85 Thus, under international law, ECS delineation and ECS delimitation are two entirely separate processes where the disposition of one has no legal effect on the results of the other. It is axiomatic, therefore, that if the legal processes differ then so do the legal statuses—each carrying with them different rights and privileges—granted through the conclusion of each procedure. Accordingly, it is in the interest of UNCLOS opponents to promote the public misperception that delimitation and delineation are the same constructs as far as UNCLOS is concerned, because only then can they further promulgate the false notion that nothing is to be gained by joining the treaty.