The Legal Nature of Rules of International Organizations: Internal or International

Since the emergence of the International Organizations, it was presumed two function for these new entities: International organizations as independent actors and as vehicles for states. In light of these two functions, two point of view about legal nature of the law produced inside IOs raised. According to the first point of view (constituent instruments as constitution) rules of international organizations just like rules of states were internal law of IOs and isolated from international law. According to second point of view (constituent instruments as a contract) rules of organizations were merely part of international law. Each of these two views have totally different effects on areas of characterization of acts, international responsibility and sequence of rules of international organizations. In this article after enumerating gaps and insufficiencies of each of these two views it is argued that adoption of a two-dimensional (internal and international) approach regarding nature of rules of international organizations, while protecting the legal autonomy of international organizations, will help to prevent fragmentation of international law .