Stability of UNCLOS regime preferrable to alternative of customary international law
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.
Opponents of UNCLOS claim that the United States should not become a party because the United States already enjoys the benefits of UNCLOS through customary law and, therefore, should not unnecessarily incur the treaty's burdens. However, this ignores the fact that customary law can change and can also be influenced by how parties to UNCLOS decide to interpret its provisions.