INTERNATIONAL LAW. Nature and sources. International law is the law gov erning, the relations between states. It is sometimes called Public International Law to distinguish it from, Private International Law or, as the latter should more properly be called, the Conflict of Laws (q. v.). Pri vate international law is the law which is applied when citizens of different nations are parties to a suit or other legal proceed ing. Since it does not involve nations them selves, but only their citizens, it has no claim to the name "international." See PRI VATE INTERNATIONAL LAW.
International law was not altogether un known among the ancients, and many in stances occur of its application by the Greek city-states, and by the Italian tribal states before the establishment of the Roman Em pire; but the development of international law into the definite and well-recognized state in which it exists today did not begin until modern times.
In 1625 Hugo van Groot, better known as Grotius, published his treatise entitled De jure belli ac pacis, which marks an era in the growth of international law. Grotius bases his system, first, upon the law of na ture, and secondly, upon the customs in ex istence between nations. He first deduces from the law of nature the principles which should properly govern the conduct of states, and he thus establishes a priori certain rules of international law. But since the law of nature is illustrated in the practices which are universally observed by mankind, Grotius found it possible to establish the rules of international law by arguing a pos teriori from the customs of nations. His system has, therefore, a double foundation.
After Grotius, certain writers, led by Pu fendorf, built up a system of international law based chiefly upon the law of nature, while another school, the Positivists, laid stress upon the positive character of inter national law as evidenced by the customs actually in existence between nations. Be tween these two schools there developed lat er a third school called the Grotian school, which takes account both of the law of na ture as the basis of international law, and of customs of nations as the embodiment of a positive system. The standpoint of the Grotian school has found greater favor among the Latin states of the continent of Europe, while the Positivist school is repre: sented by English, American and German writers, though in each case with notable exceptions.
As 'a positive science international law may be defined • as the collection of those generally accepted rules of conduct which nations consider so far binding upon them selves in their relations with one another as to lead them actually to abide by them in their general practice. Much discussion has attended the question as to how far these rules can properly lay claim to the title of "law." The Austinian school, which restricts law to the categOry of commands imposed by a political superior upon a politi cal inferior, refuses to recognize the so-call ed international law as anything more than international morality, since it lacks the elements of law-giver, command, and sanc tion. On the other hand, the school of his torical jurisprudence, of which Savigny may be regarded as the founder, taking law as the expression of the common will of a political community, maintains that inter national law possesses the character of true law inasmuch as it consists of rules adopted by the common consent of nations and en forced largely by the moral sanction of pub lic opinion. Lord Russell of Killowen, in an address before the American Bar Associ ation in 1896, considered Austin's definition as applying rather to the later development of arbitrary power than to that body of cus tomary law which, in earlier stages of socie ty, precedes law strictly so called, and which is made up of rules and customs which are laws in every real sense of the word, as, for example, the law merchant. And he contin ued: "In stages later still, as government becomes more frankly democratic, resting broadly on the popular will, laws bear less and less the character of commands imposed by a coercive authority and acquire more and more the character of customary law founded on consent." Since international law is a body of rules actually accepted by nations as regulating their mutual relations, it follows that the test of the existence of a given rule is to be found in the consent of nations to abide by that rule. Now this consent is evidenced chiefly by the usages and customs of nations, which form therefore the principal source of international law. To ascertain what these usages and customs are it has been common to turn to the writings of publicists and to the decisions of state courts. The Habana, 175 U. S. 677, 20 Sup. Ct. 290, 44 L. Ed. 320.