International law is the set of agreements and norms that govern human activities among States, and between States and non-State actors such as companies, international organizations and individuals. Its legal responsibilities cover a range of issues such as treaty compliance, the rights of individuals within State boundaries, international security and conflict resolution.
The modern international system dates back to the turn of the twentieth century, when world leaders gathered in The Hague to establish the first laws on war and peace, as well as international institutions to adjudicate disputes. However, two calamitous world wars erupted in the first half of that century, dealing a blow to the idealistic belief that international law could tame the world’s violence.
While there is a wide variation in views about the definition of international law, most writers agree that the key elements are the existence of an international community and the recognition by its members of settled rules binding upon them in their relations with one another. Some writers such as Oppenheim disagree with this view, arguing that the essential condition for the existence of law is the power to enforce it.
While international law has traditionally been confined to the activities of States, it is becoming increasingly used to regulate non-State actors such as multinational corporations, individual individuals and intergovernmental organizations. It is also being extended to include activities in outer space, global communications and world trade. The development of international law is a primary objective of the United Nations. This is reflected in the work of the International Court of Justice, the specialized agencies of the United Nations and the development of international legal instruments through multilateral treaties.