Treaty law binds only parties to the treaties. Customary international law binds all States, irrespective of whether they gave their consent. On the other hand, as we learnt in lesson 2.4., a persistent objector is not bound by the customary law that it objects to.
A State that is a persistent objector publicly objects to the customary law at the time of its formation, continues to object in a sustained manner even after the customary law comes into force and adopts a contrary practice. Because the persistent objector is not bound by the customary law, we can’t say that the persistent objector is violating the law when it adopts a different practice.
If there is sufficient number of persistent objectors made up of affected States, this can prevent the formation of the CIL.
Consider the position of a persistent objector with that of a subsequent objector. A subsequent objector objects to the customary law after it is formed. In this case, the subsequent objector continues to be bound by the customary law. If the subsequent objector adopts a contrary practice, it is violating the law and the act becomes illegal. Question: What happens if a majority of States agree with the subsequent objector?
For example, a coastal State cannot, today, decide object to the 12 NM territorial sea limit; because, this is now a well established rule in CIL. A State that seeks to unilaterally extend its territorial limit to 15 NM: (1) continues to be bound by the existing CIL and (2) if it adopts the 15NM limit, this act would be illegal because it would have violated CIL. The only exception to this is if an adequate number of States agree with 15NM limit and all the elements necessary to form a CIL are present, then a new CIL will override the old CIL.
States can enter into a treaty that overrides a specific customary international law. In this case, the parties to the treaty, in relations between them, are not bound by the CIL. Question: In this case, is it the treaty or the CIL that govern relations between a State party to a treaty and a non-State party?
If the customary law is a Jus Cogens norm State’s cannot deviate from it, either by persistent objection or by entering into a treaty.
- Bradley et al.,”Withdrawing from International Custom”, Yale Law Journal (Click here for the article). This article provoked a series of replies that can be found here.
“[...] appears to have occurred in the late nineteenth and early twentieth centuries, at a time when imperialism was at its height and most of Asia and Africa were under the control of the European powers. The “family of nations” was being expanded, but control over law creation was still largely in the hands of the so-called “civilized” nations, which meant primarily nations in Western Europe. Viewed in this context, the Mandatory View likely evolved as part of an effort to bind new nations and former colonies to international law rules that had already been worked out by a handful of powerful states. Later, when the new entrants into the system gained strength in numbers and the former powers became concerned that they might lose control of the process of law creation in the international arena, the Mandatory View was modified to allow for opting out of a CIL rule prior to the time that it became established. This right of opt out, however, was crafted in such a way as to disallow new nations from opting out of any of the CIL rules that had developed before they came into the system.
- Bradley et al., “Customary International Law and Withdrawal Rights in the Age of Treaties”, Duke Journal of Comparative and International Law (Click here for the article)
- ILA Report on the Formation of CIL: Comments 15 (Click here for the Report)
“There is fairly widespread agreement that, even if there is a persistent objector rule in international law, it applies only when the customary rule is in the process of emerging. It does not, therefore, benefit States which came into existence only after the rule matured, or which became involved in the activity in question only at a later stage. Still less can it be invoked by those who existed at the time and were already engaged in the activity which is the subject of the rule, but failed to object at that stage. In other words, there is no ‘subsequent objector’ rule.” (ILA Report)
- Anglo Norwegian Fisheries Case, ICJ, 1951 – pp. 131 held that the 10 mile rule will not apply to Norway because “[...] she has always opposed any attempt to apply it to the Norwegian coast. ” (Click here for the judgement)
- North Sea Continental Shelf Cases, ICJ (Click here for the Judgement)
“customary law rules . . . must have equal force for all members of the international community, and cannot therefore be the subject of any right of unilateral exclusion exercisable at will by any one of them in its own favour.” (North Sea Continental Shelf Case)