1. Regional Custom
Asylum case – court examines if there was a customary rule that allowed asylum to be sought in this fashion. First court determined that regional custom had to comprise the dual contents of state practice and opinion juris. Important, however, that Silence CANNOT Constitute State Practice in regional custom. One must create regional customs actively, not passively.
2. Persistent Objection
If one objects persistently, then one is not subject to custom. For example, the USA has persistently objected to Canada’s claim that northwest passage is part of internal waters.