How Custom Evolves

The two-element doctrine allows for change only at a slow pace and is premised on the existence of a community of states that is both internally cohesive and whose members share common values and principles. Sudden transformations in customary law cannot be explained through the two-element doctrine, but rather should be viewed as a change of law, to which a state or the international community acquiesces. However, all these perspectives offer at best only a fragmented picture of how customary rules evolve. In order to fully grasp the potential and process of customary rules change, one has to examine them in the system within which they operate, and in the context of their interactions with other rules. Such interactions may lead to conflict with preexisting customary rules, and it is through such conflicts that change may come about, and new rules may be created.