International law is different from national law in that it does not derive from the parliamentary legislation or judicial case-law of any one state: there is no legislature, executive, or judiciary in the international realm. There is no system of courts with a comprehensive and compulsory jurisdiction to interpret the law. International law is, however, crucial for the maintenance of peace and security of world affairs. Moreover, as international law advances and evolves we see a more accurate measurement of progress in our societies.
Sources of International Law
The sources of international law are many: treaties, customary law, and even judicial decisions by the international courts.
Article 38(1) of the Statute of the International Court of Justice is considered the most authoritative and complete statement as to the sources of international law:
"the Court, whose function is to decide in acordance with international law such disputes as are submitted to it, shall apply: (a) international conventions, whether general or particular, establishing rules expressly recognised by the contesting states; (b) international custom, as evidence of a general practice accepted as law; (c) the general principles of law recognised by civilised nations; (d) subject to the provisions of Article 59, judicial decisions and the teachings of the most highly qualified publicists of the various nations, as subsidiary means for the determination of rules of law."
Measuring progress and International Law
International law is the bi-product of unsustainable international wars between nation-states, that serves to settle disputes, maintain security, advance commerce and in general, progress peace and better protect human rights.
As with National Law, measuring progress in societies through the development of international law is an important indicator of how well global civil society has progressed and is still progressing. Do the rules of international law respect the basic rights of all peoples living within its jurisdiction? Do women have the right to vote? Are human rights protected under its laws?
The Oxford Dictionary defines law as "the system of rules which a particular country or community recognizes as regulating the actions of its members and which it may enforce by the imposition of penalties." Thus, on an international scope, what is the capacity of the international legal system in protecting and defending people's basic human rights.