The International Law of the Sea: A Treaty for Thee; Customary Law for Me?
Craig Allen argues against the claim that U.S. already realizes all benefits of UNCLOS from customary international law by looking at the consequences if all other 160+ nations followed the U.S. example.
Putting aside for now the potential consequences of blurring the distinction between broadly ratified convention regimes and customary law for other subject areas of concern (e.g., the 1977 Additional Protocols to the Geneva Conventions and the Rome Statute for the ICC), one might reasonably ask what response such a position might invite from other states that are now parties to the LOSC. Could they too circumvent the LOSC’s ban on reservations and avoid its compulsory dispute settlement provisions by renouncing the LOSC in favor of customary law? Even if empirically sound, the argument that nothing is to be gained by the United States in ratifying the LOSC, because all of the best parts either codified existing customary law when the Convention was opened for signature or later (i.e., between 1982 and 1994, when it entered into force) ripened into customary law, must be tested against the fallacy of composition. If that is true for the U.S., wouldn’t it also be true for the 160+ nations that are already parties to the LOSC? In short, do regimes founded on rules of customary law better serve the national and shared interests than those founded on treaties?
The common understanding of the fallacy of composition is that what might be true for the one is not necessarily true for the many. If one person in a crowd stands on tiptoes to see better he might be better off, but if everyone does it no one is better off. The economist John Maynard Keynes referred to the analogous “paradox of thrift,” by which he meant that if one person saves a substantial portion of her earnings she may be better off, but if everyone saved as much it could lead to a recession.
The Convention reduces, but doesn’t wholly eliminate, the indeterminacy inherent in customary law. The Convention also provides greater stability and predictability. Here it should be noted that the LOS Convention’s articles can only be amended through an elaborate process that, by design, provides the kind of stability the U.S. has long sought in the maritime domain. By contrast, customary law rules evolve by the practice of nations asserting, acceding to or persistently objecting to new norms, thus introducing unwelcome uncertainty into the nation’s maritime affairs. Moreover, as Edwin Williamson, President George H.W. Bush’s State Department Legal Advisor noted, the history of customary international law “reflects a steady deterioration of the freedom of the seas to the detriment of the essential rights of maritime nations, such as the U.S.”
Those who believe the costs of ratification outweigh the benefits, because most of the benefits are already provided by customary law, might want to consider the global state of affairs that would unfold if the 160+ nations that are already a party to the Convention—including the critical straits states—chose to follow the U.S. lead and eschew adherence to a meticulously drafted convention in favor of malleable customary law rules. While the Convention’s 320 articles and 9 annexes are not always a model of precision, one can certainly question whether the Convention ambiguities the opponents point to are any clearer under the corresponding customary law and whether rule stability is better served by a conventional regime or the practice of 160+ states.