International Law - Antonio Cassese

Oxford University Press

First edition 2001 - p.86-113

Second edition 2005 – p.46-71

Unit 3.

INTERNATIONAL LAWMAKING:
CUSTOM AND TREATIES

TRADITIONAL LAW

From the beginning of the international community States have evolved two principal methods for creating legally binding rules: treaties and custom. Both were admirably suited to the exigencies of their creators. Both responded to the basic need of not imposing obligations on States that did not wish to be bound by them. No outside ‘legislator’ was tolerated: law was brought into being by the very States that were to be bound by it.

Treaties in particular, being applicable to the contracting parties only, perfectly reflected the individualism prevailing in the international community. Custom, although it gave rise to rules binding on all members of the community, also ultimately rested on consent.

The unfettered freedom of States was reflected in another feature of international lawmaking: the absence of any hierarchy between custom and treaties as sources of law. In other words, rules created by means of bilateral or multilateral treaties were not stronger than, or superior to, customary or 'general' rules, and vice versa. Both sets of rules possessed equal rank and status.