The notion of law of international organizations may assume 2 different needs: 1)firstly it may refer
to the secondary rules (rules on the rules) produced by international organizations and 2)second it
may refer to primary rules (rules of behavior, they set a prohibition) of international organizations.
1. the rules on the establishment, the functioning, and the law production of the
international organization. The secondary rules set all the mechanism that runs the
international organization and allow to produce primary rules.
2. Primary rules are binding upon the member states, when they are not they fall in the
category of soft law instruments. When the inter org enjoys a general scope the
primary rules can encompass any subject matter (case of the UNGA's resolutions).
Historical intro
This phenomenon is a relatively recent one, some inter org existed even before the second WW;
during the last decades of the 19th century the European states enjoyed an unprecedented period
of peace and prosperity, followed by scientific development that led to a shift from an approach of
competition to one of cooperation. This shift was mainly due to the necessity of a more efficient
management of common resources and international trade => the first int org stood out for their
scientific and technical focus, they were established by a treaty and they had a Committee and a
permanent administrative body composed by officials; because they focused on technical issues they
were short of any political scope. Only a breaking event such as the first WW led to a speed up;
already in 1920 the League of Nations was established, that was followed also by the establishment
of the first international court, the Permanent Court of International Justice. From the 1920 to the
end of the second WW the use of force was still legal to use in settling international disputes, after
the first War it was intended as the last resort. The League of Nations failed to carry out its mission
as it was unable to stop the outrages of the second WW. The end of the second WW is traditionally
marked as the moment in which the international society turns into the international community,
the economic development and the globalization brought up an interdependence between states.
And this was the perfect environment for int org to flourish, from 60 in 1979 to about 3050 today.
How international organizations are established
An international organization can be defined as a collectivity of states established by a treaty with a
constitution and common organs having a personality distinct from that of its member states and
being a subject of international law, with its treaty making capacity. This definition was then
elaborated by the ILC in the Draft articles on the Responsibility of International Organization (DARIO)
--> within it we have art 2 letter a) which defines an international organization as an organization
established by a treaty or other instrument governed by international law and possessing its own
international personality.
There are 2 elements which stem out from these definitions: the existence of a constitutional basis,
and the legal personality of international organizations (and thus int org are able to express their
own will, which is separate from that of member states). So by way of their organs they are also able
to entertain independent international relationships with other states or int org.
International organizations are established by an international law instrument, which normally
corresponds to a treaty, but it could be a different instrument. An ex is the Organization of
Petroleum Exporting (OPEC), established by means of an oral agreement; another example is by
means of an act of an international organization (such as a resolution of the GA). This brings the
issue of to what extent a teleological interpretation of the treaty which establishes the international
organization may be read as allowing the international organization to carry out some activities, and
to have some powers not expressively provided for in the establishing treaty (imply powers).
The fact that the instrument has to be an international instrument allows international organizations
to be distinguished from non-governmental organizations. The difference is that while int org are