From Lecture II. of “International Law.”

THERE has been a difference of opinion among writers concerning the foundation of the Law of Nations. It has been considered by some as a mere system of positive institutions, founded upon consent and usage; while others have insisted that it was essentially the same as the Law of Nature, applied to the conduct of nations, in the character of moral persons, susceptible of obligations and laws. We are not to adopt either of these theories as exclusively true. The most useful and practical part of the Law of Nations is, no doubt, instituted or positive law, founded on usage, consent, and agreement. But it would be improper to separate this law entirely from natural jurisprudence, and not to consider it as deriving much of its force and dignity from the same principles of right reason, the same views of the nature and constitution of man, and the same sanction of Divine revelation, as those from which the science of morality is deduced. There is a natural and a positive Law of Nations. By the former every state, in its relations with other states, is bound to conduct itself with justice, good faith, and benevolence; and this application of the Law of Nature has been called by Vattel the necessary Law of Nations, because nations are bound by the Law of Nature to observe it; and it is termed by others the internal Law of Nations, because it is obligatory upon them in point of conscience. We ought not, therefore, to separate the science of public law from that of ethics, nor encourage the dangerous suggestion that governments are not so strictly bound by the obligations of truth, justice, and humanity, in relation to other powers, as they are in the management of their own local concerns.

  States, or bodies politic, are to be considered as moral persons, having a public will, capable and free to do right and wrong, inasmuch as they are collections of individuals, each of whom carries with him into the service of the community the same binding law of morality and religion which ought to control his conduct in private life. The Law of Nations is a complex system, composed of various ingredients. It consists of general principles of right and justice, equally suitable to the government of individuals in a state of natural equality, and to the relations and conduct of nations; of a collection of usages, customs, and opinions, the growth of civilization and commerce; and of a code of positive law.

  In the absence of these latter regulations, the intercourse and conduct of nations are to be governed by principles fairly to be deduced from the rights and duties of nations, and the nature of moral obligation; and we have the authority of the lawyers of antiquity, and of some of the first masters in the modern school of public law, for placing the moral obligation of nations and of individuals on similar grounds, and for considering individual and national morality as parts of one and the same science. The Law of Nations, so far as it is founded on the principles of Natural Law, is equally binding in every age and upon all mankind. But the Christian nations of Europe, and their descendants on this side of the Atlantic, by the vast superiority of their attainments in arts, and science, and commerce, as well as in policy and government; and, above all, by the brighter light, the more certain truths, and the more definite sanction which Christianity has communicated to the ethical jurisprudence of the Ancients, have established a Law of Nations peculiar to themselves. They form together a community of Nations united by religion, manners, morals, humanity, and science, and united also by the mutual advantages of commercial intercourse, by the habit of forming alliances and treaties with each other, of interchanging embassadors, and of studying and recognizing the same writers and systems of public law.

  This Jus Gentium of the Imperial jurisconsults is identical with the Law of Nature, or Natural Law, of many modern ethical and juridical writers; and both are, in fact, the law of God, made known somewhat dimly to the whole human race at all times, and set forth with unmistakable certainty and transcendent power in his revealed will. This is, in truth, the highest law by which moral beings can be governed; highest in its Lawgiver, who is omnipotent over each individual man, as well as over societies and states; highest in the absolute perfection of the rules which it contains; highest in the absolute cogency of the commands which it utters; highest in the absolute obligation of duties which it enforces; highest in the absolute certainty and irresistible coercive power of the sanctions which it wields, and which operate upon the deepest spiritual nature of every human being….

  In more ancient times, and to a great extent even at this day, in that Eastern portion of the world in which so much of the usages of earlier mankind still survive, systems of religion and systems of morals, generally drawing with them some system of laws, gain currency by their own moral influence; certain minds being naturally predisposed to receive them acquiesce in them even with enthusiasm. Mr. Justice Stephen, in the controversial work which he calls “Liberty, Equality, and Fraternity,” has an eloquent passage on the subject. “The sources of religion lie hid from us. All that we know is, that now and again in the course of ages some one sets to music the tune which is haunting millions of ears. It is caught up here and there, and repeated till the chorus is thundered out by a body of singers able to drown all discords and to force the vast unmusical mass to listen to them. Such results as these come not by observation, but when they do come they carry away as with a flood and hurry in their own direction all the laws and customs of those whom they affect.” What is here said of religion is true to a certain extent of morality. In the East a body of new moral ideas is sure in time to produce a string of legal rules; and it is said by those who know India and its natives well that the production of what for want of a better name we must call a Code is a favorite occupation with learned and active minds, though of course in a country which nowadays follows to a great extent the morality (though not the faith) of Christian Europe, and receives new laws from a regularly constituted Legislature, the enthusiasm for new moral doctrines is ever growing feebler and the demand for legal rules accommodated to them is becoming less. Now, International Law was a Code in the same sense in which many Eastern collections of rules were Codes. It was founded on a new morality, that which had been discovered in the supposed Law of Nature, and in some minds it excited unbounded enthusiasm.

  The same process had previously been followed in Europe as regards Roman Civil Law. We may not quite understand the admiration which the technical part of the Roman Law inspired, but of the fact there is no doubt. This process by which laws extended themselves had not quite died out when the international jurists appeared, and in point of fact their system of rules was received by the world very much as a system of law founded on morals is received to this day in the East. No doubt it fell on soil prepared for it. The literate classes, the scholars, great parts of the clergy, and the sovereigns and statesmen of Europe accepted it, and the result was an instant decay of the worst atrocities of war. Indeed, it is only necessary to look at the earliest authorities on International Law, in the “De Jure Belli et Pacis” of Grotius for example, to see that the Law of Nations is essentially a moral, and, to some extent, a religious, system. The appeal of Grotius is almost as frequent to morals and religion as to precedent, and no doubt it is these portions of the book, which to us have become almost commonplace or which seem irrelevant, which gained for it much of the authority which it ultimately obtained.