International law is the law which governs the relationships between separate sovereign nations; although the United Nations has the authority in some instances to issue mandates. It is normally created by treaties and conventions signed by two or more countries. It governs such issues as territorial waters, shipwrecks, etc. Also since the laws of different nations often conflict with each other, International Law offers a medium to resolve those conflicts.
An important element of international law was the establishment of the International Court of Justice which sits at The Hague. It tries such cases as "crimes against humanity" and also resolves disputes between nations. Its decisions are not binding on any nation-if so the nation would have surrendered its sovereignty--but it can issue rulings which determine appropriate solutions to international disputes. The citation below provides a far more elaborate description.
International law, also called the law of nations, is a body of rules that governs conduct among nations. It is comprised of a complicated web of treaties (agreements between two or among several nations), laws based on customs, legal writings, and conventions (international agreements). In 1625 Dutch legal scholar Hugo Grotius (1583–1645) published Concerning the Law of War and Peace, which served as a basis of international law. In this work he asserted that every state in the world is sovereign (independent) and legally equally to all other states. He also argued that natural law (a body of law that is derived from nature and is therefore binding upon human society) defines rules of conduct for nations as well as individuals; therefore nations are accountable to common principles, which are higher than the laws of a nation.
At the time everyone did not agree with Grotius's idea. For instance, English philosopher Thomas Hobbes (1588–1679) discarded the notion of natural law as being superior to the laws of a nations. International law is unenforceable, he said, because there is no legal body higher than that of a nation. Since the seventeenth century, however, the concept of international law has gained acceptance. During the nineteenth and twentieth centuries, the Geneva Conventions (1864) and The Hague (Netherlands) Conferences (1889, 1907, 1914) laid down rules for war, although these rules were often disregarded. The International Court of Justice, which is part of the United Nations (an international peace-keeping organization), now enforces international laws.
Further Information: Reed, Paul S. "International Law." Current Events: Law. [Online] Available http://law.about.com/newsissues/law/cs/internationallaw/index.htm?terms=international+law, October 30, 2000; Spies, Karen B. Isolation vs. Intervention. New York: Twenty-First Century Books, 1995; United Nations. International Law. [Online] Available http://www.un.org/law/, October 30, 2000.