Vienna Convention on the Law of Treaties
International organizations commonly have the power to conclude treaties as well. A notable example is the European Union, which has concluded a number of free trade agreements. The Vienna Convention on the Law of Treaties between States and International Organizations or between International Organizations aims to be an extension to the Vienna Convention on the Law of Treaties and deals with treaties between one or more states and one or more international organizations and between international organizations. However, this Vienna Convention is not yet into force as of 2013 due to insufficient number of ratifications. One of the most extensive cases on international organizations’ treaty-making power is the Advisory Opinion of the International Court of Justice titled, "Reparation for Injuries Suffered in the Service of the United Nations", which details the relationship between sovereignty and the obligation to pay reparation, as well as the criteria to determine international legal personality.