§ 17. Custom is the older and the original source of International Law in particular as well as of law in general. Custom must not be confounded with usage. In everyday life and language both terms are used synonymously, but in the language of the jurist they have two distinctly different meanings. Jurists speak of a custom, when a clear and continuous habit of doing certain actions has grown up under the ægis of the conviction that these actions are legally necessary or legally right. On the other hand, jurists speak of a usage, when a habit of doing certain actions has grown up without there being the conviction of their legal character. Thus the term "custom" is in juristic language a narrower conception than the term "usage," as a given course of conduct may be usual without being customary. Certain conduct of States concerning their international relations may therefore be usual without being the outcome of customary International Law.

As usages have a tendency to become custom, the question presents itself, at what time a usage turns into a custom. This question is one of fact, not of theory. All that theory can point out is this: Wherever and as soon as a frequently adopted international conduct of States is considered legally necessary or legally right, the rule which may be abstracted from such conduct, is a rule of customary International Law.

§ 18. Treaties are the second source of International Law, and a source which has of late become of the greatest importance. As treaties may be concluded for innumerable purposes,[14] it is necessary to emphasise that such treaties only are a source of International Law as either stipulate new rules for future international conduct or confirm, define, or abolish existing customary or conventional rules. Such treaties must be called law-making treaties. Since the Family of Nations is not a State-like community, there is no central authority which could make law for it in a similar way as Parliaments make law by statutes within the States. The only way in which International Law can be made by a deliberate act, in contradistinction to custom, is that the members of the Family of Nations conclude treaties in which certain rules for their future conduct are stipulated. Of course, such law-making treaties create law for the contracting parties solely. Their law is universal International Law then only, when all the members of the Family of Nations are parties to them. Many law-making treaties are concluded by a few States only, so that the law which they create is particular International Law. On the other hand, there have been many law-making treaties concluded which contain general International Law, because the majority of States, including leading Powers, are parties to them. General International Law has a tendency to become universal because such States as hitherto did not consent to it will in future either expressly give their consent or recognise the respective rules tacitly through custom.[15] But it must be emphasised that, whereas custom is the original source of International Law, treaties are a source the power of which derives from custom. For the fact that treaties can stipulate rules of international conduct at all is based on the customary rule of the Law of Nations, that treaties are binding upon the contracting parties.[16]

§ 19. Thus custom and treaties are the two exclusive sources of the Law of Nations. When writers on International Law frequently enumerate other sources besides custom and treaties, they confound the term "source" with that of "cause" by calling sources of International Law such factors as influence the gradual growth of new rules of International Law without, however, being the historical facts from which these rules receive their legal force. Important factors of this kind are: Opinions of famous writers[17] on International Law, decisions of prize courts, arbitral awards,[18] instructions issued by the different States for the guidance of their diplomatic and other organs, State Papers concerning foreign politics, certain Municipal Laws, decisions of Municipal Courts.[19] All these and other factors may influence the growth of International Law either by creating usages which gradually turn into custom, or by inducing the members of the Family of Nations to conclude such treaties as stipulate legal rules for future international conduct.

A factor of a special kind which also influences the growth of International Law is the so-called Comity (Comitas Gentium, Convenance et Courtoisie Internationale, Staatengunst). In their intercourse with one another, States do observe not only legally binding rules and such rules as have the character of usages, but also rules of politeness, convenience, and goodwill. Such rules of international conduct are not rules of law, but of comity. The Comity of Nations is certainly not a source of International Law, as it is distinctly the contrast to the Law of Nations. But there can be no doubt that many a rule which formerly was a rule of International Comity only is nowadays a rule of International Law. And it is certainly to be expected that this development will go on in future also, and that thereby many a rule of present International Comity will in future become one of International Law.[20]

Not to be confounded with the rules of Comity are the rules of morality which ought to apply to the intercourse of States as much as to the intercourse of individuals.

IV RELATIONS BETWEEN INTERNATIONAL AND MUNICIPAL LAW

Holtzendorff in Holtzendorff, I. pp. 49-53, 117-120—Nys, I. pp. 185-189—Taylor, § 103—Holland, Studies, pp. 176-200—Kaufmann, "Die Rechtskraft des internationalen Rechts" (1899)—Triepel, "Völkerrecht und Landesrecht" (1899)—Anzilotti, "Il diritto internazionale nei giudizi interni" (1905)—Kohler in Z.V. II. (1908), pp. 209-230.

§ 20. The Law of Nations and the Municipal Law of the single States are essentially different from each other. They differ, first, as regards their sources. Sources of Municipal Law are custom grown up within the boundaries of the respective State and statutes enacted by the law-giving authority. Sources of International Law are custom grown up within the Family of Nations and law-making treaties concluded by the members of that family.

The Law of Nations and Municipal Law differ, secondly, regarding the relations they regulate. Municipal Law regulates relations between the individuals under the sway of the respective State and the relations between this State and the respective individuals. International Law, on the other hand, regulates relations between the member States of the Family of Nations.

The Law of Nations and Municipal Law differ, thirdly, with regard to the substance of their law: whereas Municipal Law is a law of a Sovereign over individuals subjected to his sway, the Law of Nations is a law not above, but between Sovereign States, and therefore a weaker law.[21]

§ 21. If the Law of Nations and Municipal Law differ as demonstrated, the Law of Nations can neither as a body nor in parts be per se a part of Municipal Law. Just as Municipal Law lacks the power of altering or creating rules of International Law, so the latter lacks absolutely the power of altering or creating rules of Municipal Law. If, according to the Municipal Law of an individual State, the Law of Nations as a body or in parts is considered the law of the land, this can only be so either by municipal custom or by statute, and then the respective rules of the Law of Nations have by adoption[22] become at the same time rules of Municipal Law. Wherever and whenever such total or partial adoption has not taken place, municipal courts cannot be considered to be bound by International Law, because it has, per se, no power over municipal courts.[23] And if it happens that a rule of Municipal Law is in indubitable conflict with a rule of the Law of Nations, municipal courts must apply the former. If, on the other hand, a rule of the Law of Nations regulates a fact without conflicting with, but without expressly or tacitly having been adopted by Municipal Law, municipal courts cannot apply such rule of the Law of Nations.

§ 22. If Municipal Courts cannot apply unadopted rules of the Law of Nations, and must apply even such rules of Municipal Law as conflict with the Law of Nations, it is evident that the several States, in order to fulfil their international obligations, are compelled to possess certain rules, and are prevented from having certain other rules as part of their Municipal Law. It is not necessary to enumerate all the rules of Municipal Law which a State must possess, and all those rules it is prevented from having. It suffices to give some illustrative examples. Thus, on the one hand, the Municipal Law of every State, for instance, is compelled to possess rules granting the necessary privileges to foreign diplomatic envoys, protecting the life and liberty of foreign citizens residing on its territory, threatening punishment for certain acts committed on its territory in violation of a foreign State. On the other hand, the Municipal Law of every State is prevented by the Law of Nations from having rules, for instance, conflicting with the freedom of the high seas, or prohibiting the innocent passage of foreign merchantmen through its maritime belt, or refusing justice to foreign residents with regard to injuries committed on its territory to their lives, liberty, and property by its own citizens. If a State does nevertheless possess such rules of Municipal Law as it is prevented from having by the Law of Nations, or if it does not possess such Municipal rules as it is compelled to have by the Law of Nations, it violates an international legal duty, but its courts[24] cannot by themselves alter the Municipal Law to meet the requirements of the Law of Nations.

§ 23. However, although Municipal Courts must apply Municipal Law even if conflicting with the Law of Nations, there is a presumption against the existence of such a conflict. As the Law of Nations is based upon the common consent of the different States, it is improbable that a civilised State would intentionally enact a rule conflicting with the Law of Nations. A part of Municipal Law, which ostensibly seems to conflict with the Law of Nations, must, therefore, if possible, always be so interpreted as essentially not containing such conflict.

§ 24. In case of a gap in the statutes of a civilised State regarding certain rules necessitated by the Law of Nations, such rules ought to be presumed by the Courts to have been tacitly adopted by such Municipal Law. It may be taken for granted that a State which is a member of the Family of Nations does not intentionally want its Municipal Law to be deficient in such rules. If, for instance, the Municipal Law of a State does not by a statute grant the necessary privileges to diplomatic envoys, the courts ought to presume that such privileges are tacitly granted.

§ 25. There is no doubt that a State need not make use of all the rights it has by the Law of Nations, and that, consequently, every State can by its laws expressly renounce the whole or partial use of such rights, provided always it is ready to fulfil such duties, if any, as are connected with these rights. However, when no such renunciation has taken place, Municipal Courts ought, in case the interests of justice demand it, to presume that their Sovereign has tacitly consented to make use of such rights. If, for instance, the Municipal Law of a State does not by a statute extend its jurisdiction over its maritime belt, its courts ought to presume that, since by the Law of Nations the jurisdiction of a State does extend over its maritime belt, their Sovereign has tacitly consented to that wider range of its jurisdiction.

A remarkable case illustrating this happened in this country in 1876. The German vessel Franconia, while passing through the British maritime belt within three miles of Dover, negligently ran into the British vessel Strathclyde, and sank her. As a passenger on board the latter was thereby drowned, the commander of the Franconia, the German Keyn, was indicted at the Central Criminal Court and found guilty of manslaughter. The Court for Crown Cases Reserved, however, to which the Central Criminal Court referred the question of jurisdiction, held by a majority of one judge that, according to the law of the land, English courts had no jurisdiction over crimes committed in the English maritime belt. Keyn was therefore not punished.[25] To provide for future cases of like kind, Parliament passed, in 1878, the "Territorial Waters Jurisdiction Act."[26]

V DOMINION OF THE LAW OF NATIONS

Lawrence, § 44—Phillimore, I. §§ 27-33—Twiss, I. § 62—Taylor, §§ 61-64—Westlake, I. p. 40—Bluntschli, §§ 1-16—Heffter, § 7—Holtzendorff in Holtzendorff, I. pp. 13-18—Nys, I. pp. 116-132—Rivier, I. § 1—Bonfils, Nos. 40-45—Despagnet, Nos. 51-53—Martens, I. § 41—Fiore, Code, Nos. 38-43—Ullmann, § 10—Nippold in Z.V. II. (1908), pp. 441-443—Cavaglieri in R.G. XVIII. (1911), pp. 259-292.

§ 26. Dominion of the Law of Nations is the name given to the area within which International Law is applicable—that is, those States between which International Law finds validity. The range of the dominion of the Law of Nations is controversial, two extreme opinions concerning this dominion being opposed. Some publicists[27] maintain that the dominion of the Law of Nations extends as far as humanity itself, that every State, whether Christian or non-Christian, civilised or uncivilised, is a subject of International Law. On the other hand, several jurists[28] teach that the dominion of the Law of Nations extends only as far as Christian civilisation, and that Christian States only are subjects of International Law. Neither of these opinions would seem to be in conformity with the facts of the present international life and the basis of the Law of Nations. There is no doubt that the Law of Nations is a product of Christian civilisation. It originally arose between the States of Christendom only, and for hundreds of years was confined to these States. Between Christian and Mohammedan nations a condition of perpetual enmity prevailed in former centuries. And no constant intercourse existed in former times between Christian and Buddhistic States. But from about the beginning of the nineteenth century matters gradually changed. A condition of perpetual enmity between whole groups of nations exists no longer either in theory or in practice. And although there is still a broad and deep gulf between Christian civilisation and others, many interests, which knit Christian States together, knit likewise some non-Christian and Christian States.

§ 27. Thus the membership of the Family of Nations has of late necessarily been increased, and the range of the dominion of the Law of Nations has extended beyond its original limits. This extension has taken place in conformity with the basis of the Law of Nations. As this basis is the common consent of the civilised States, there are three conditions for the admission of new members into the circle of the Family of Nations. A State to be admitted must, first, be a civilised State which is in constant intercourse with members of the Family of Nations. Such State must, secondly, expressly or tacitly consent to be bound for its future international conduct by the rules of International Law. And, thirdly, those States which have hitherto formed the Family of Nations must expressly or tacitly consent to the reception of the new member.

The last two conditions are so obvious that they need no comment. Regarding the first condition, however, it must be emphasised that not particularly Christian civilisation, but civilisation of such kind only is conditioned as to enable the State concerned and its subjects to understand and to act in conformity with the principles of the Law of Nations. These principles cannot be applied to a State which is not able to apply them on its own part to other States. On the other hand, they can well be applied to a State which is able and willing to apply them to other States, provided a constant intercourse has grown up between it and other States. The fact is that the Christian States have been of late compelled by pressing circumstances to receive several non-Christian States into the community of States which are subjects of International Law.

§ 28. The present range of the dominion of International Law is a product of historical development within which epochs are distinguishable marked by successive entrances of various States into the Family of Nations.

(2) The next group of States which entered into the Family of Nations is the body of Christian States which grew up outside Europe. All the American[29] States which arose out of colonies of European States belong to this group. And it must be emphasised that the United States of America have largely contributed to the growth of the rules of International Law. The two Christian Negro Republics of Liberia in West Africa and of Haiti on the island of San Domingo belong to this group.

(3) With the reception of the Turkish Empire into the Family of Nations International Law ceased to be a law between Christian States solely. This reception has expressly taken place through Article 7 of the Peace Treaty of Paris of 1856, in which the five Great European Powers of the time, namely, France, Austria, England, Prussia, and Russia, and besides those Sardinia, the nucleus of the future Great Power Italy, expressly "déclarent la Sublime Porte admise à participer aux avantages du droit public et du concert européens." Since that time Turkey has on the whole endeavoured in time of peace and war to act in conformity with the rules of International Law, and she has, on the other hand, been treated[30] accordingly by the Christian States. No general congress has taken place since 1856 to which Turkey has not been invited to send her delegates.

(4) Another non-Christian member of the Family of Nations is Japan. A generation ago one might have doubted whether Japan was a real and full member of that family, but since the end of the nineteenth century no doubt is any longer justified. Through marvellous efforts, Japan has become not only a modern State, but an influential Power. Since her war with China in 1895, she must be considered one of the Great Powers that lead the Family of Nations.

(5) The position of such States as Persia, Siam, China, Morocco, Abyssinia, and the like, is doubtful. These States are certainly civilised States, and Abyssinia is even a Christian State. However, their civilisation has not yet reached that condition which is necessary to enable their Governments and their population in every respect to understand and to carry out the command of the rules of International Law. On the other hand, international intercourse has widely arisen between these States and the States of the so-called Western civilisation. Many treaties have been concluded with them, and there is full diplomatic intercourse between them and the Western States. China, Persia, and Siam have even taken part in the Hague Peace Conferences. All of them make efforts to educate their populations, to introduce modern institutions, and thereby to raise their civilisation to the level of that of the Western. They will certainly succeed in this respect in the near future. But as yet they have not accomplished this task, and consequently they are not yet able to be received into the Family of Nations as full members. Although they are, as will be shown below (§ 103), for some parts within the circle of the Family of Nations, they remain for other parts outside. But the example of Japan can show them that it depends entirely upon their own efforts to be received as full members into that family.

(6) It must be mentioned that a State of quite a unique character, the former Congo Free State,[31] was, since the Berlin Conference of 1884-1885, a member of the Family of Nations. But it lost its membership in 1908 when it merged in Belgium by cession.

§ 29. The Law of Nations as a law between States based on the common consent of the members of the Family of Nations naturally does not contain any rules concerning the intercourse with and treatment of such States as are outside that circle. That this intercourse and treatment ought to be regulated by the principles of Christian morality is obvious. But actually a practice frequently prevails which is not only contrary to Christian morality, but arbitrary and barbarous. Be that as it may, it is discretion, and not International Law, according to which the members of the Family of Nations deal with such States as still remain outside that family. But the United States of America apply, as far as possible, the rules of International Law to their relations with the Red Indians.

VI CODIFICATION OF THE LAW OF NATIONS

Holtzendorff in Holtzendorff, I. pp. 136-152—Ullmann, § 11—Despagnet, Nos. 67-68—Bonfils, Nos. 1713-1727—Mérignhac, I. pp. 26-28—Nys, I. pp. 166-183—Rivier, I. § 2—Fiore, I. Nos. 124-127—Martens, I. § 44—Holland, Studies, pp. 78-95—Bergbohm, "Staatsverträge und Gesetze als Quellen des Völkerrechts" (1877), pp. 44-77—Bulmerincq, "Praxis, Theorie, und Codification des Völkerrechts" (1874), pp. 167-192—Roszkowski in R.I. XXI. (1889), p. 520—Proceedings of the American Society of International Law, IV. (1910), pp. 208-227.

§ 30. The lack of precision which is natural to a large number of the rules of the Law of Nations on account of its slow and gradual growth has created a movement for its codification. The idea of a codification of the Law of Nations in its totality arose at the end of the eighteenth century. It was Bentham who first suggested such a codification. He did not, however, propose codification of the existing positive Law of Nations, but thought of a utopian International Law which could be the basis of an everlasting peace between the civilised States.[32]

Another utopian project is due to the French Convention, which resolved in 1792 to create a Declaration of the Rights of Nations as a pendant to the Declaration of the Rights of Mankind of 1789. For this purpose the Abbé Grégoire was charged with the drafting of such a declaration. In 1795, Abbé Grégoire produced a draft of twenty-one articles, which, however, was rejected by the Convention, and the matter dropped.[33]

It was not until 1861 that a real attempt was made to show the possibility of a codification. This was done by an Austrian jurist, Alfons von Domin-Petrushevecz, who published in that year at Leipzig a "Précis d'un Code de Droit International."

In 1862, the Russian Professor Katschenowsky brought an essay before the Juridical Society of London (Papers II. 1863) arguing the necessity of a codification of International Law.

In 1863, Professor Francis Lieber, of the Columbia College, New York, drafted the Laws of War in a body of rules which the United States published during the Civil War for the guidance of her army.[34]

In 1868, Bluntschli, the celebrated Swiss interpreter of the Law of Nations, published "Das moderne Völkerrecht der civilisirten Staaten als Rechtsbuch dargestellt." This draft code has been translated into the French, Greek, Spanish, and Russian languages, and the Chinese Government produced an official Chinese translation as a guide for Chinese officials.

In 1872, the great Italian politician and jurist Mancini raised his voice in favour of codification of the Law of Nations in his able essay "Vocazione del nostro secolo per la riforma e codificazione del diritto delle genti."

Likewise in 1872 appeared at New York David Dudley Field's "Draft Outlines of an International Code."

In 1873 the Institute of International Law was founded at Ghent in Belgium. This association of jurists of all nations meets periodically, and has produced a number of drafts concerning various parts of International Law, and in especial a Draft Code of the Law of War on Land (1880).

Likewise in 1873 was founded the Association for the Reform and Codification of the Law of Nations, which also meets periodically and which styles itself now the International Law Association.

In 1874 the Emperor Alexander II. of Russia took the initiative in assembling an international conference at Brussels for the purpose of discussing a draft code of the Law of Nations concerning land warfare. At this conference jurists, diplomatists, and military men were united as delegates of the invited States, and they agreed upon a body of sixty articles which goes under the name of The Declaration of Brussels. But the Powers have never ratified these articles.

In 1880 the Institute of International Law published its "Manuel des Lois de la Guerre sur Terre."

In 1887 Leone Levi published his "International Law with Materials for a Code of International Law."

In 1890 the Italian jurist Fiore published his "Il diritto internazionale codificato e sua sanzione giuridica," of which a fourth edition appeared in 1911.

In 1906 E. Duplessix published his "La loi des Nations. Projet d'institution d'une autorité nationale, législative, administrative, judiciaire. Projet de Code de Droit international public."

In 1911 Jerome Internoscia published his "New Code of International Law" in English, French, and Italian.

§ 31. At the end of the nineteenth century, in 1899, the so-called Peace Conference at the Hague, convened on the personal initiative of the Emperor Nicholas II. of Russia, has shown the possibility that parts of the Law of Nations may well be codified. Apart from three Declarations of minor value and of the convention concerning the adaptation of the Geneva Convention to naval warfare, this conference has succeeded in producing two important conventions which may well be called codes—namely, first, the "Convention for the Pacific Settlement of International Disputes," and, secondly, the "Convention with respect to the Laws and Customs of War on Land." The great practical importance of the first-named convention is now being realised, as the Permanent Court of Arbitration has in a number of cases already successfully given its award. Nor can the great practical value of the second-named convention be denied. Although the latter contains, even in the amended form given to it by the second Hague Peace Conference of 1907, many gaps, which must be filled up by the customary Law of Nations, and although it is not a masterpiece of codification, it represents a model, the very existence of which teaches that codification of parts of the Law of Nations is practicable, provided the Powers are inclined to come to an understanding. The first Hague Peace Conference has therefore made an epoch in the history of International Law.

§ 32. Shortly after the Hague Peace Conference of 1899, the United States of America took a step with regard to sea warfare similar to that taken by her in 1863 with regard to land warfare. She published on June 27, 1900, a body of rules for the use of her navy under the title "The Laws and Usages of War at Sea"—the so-called "United States Naval War Code"—which was drafted by Captain Charles H. Stockton, of the United States Navy.

Although, on February 4, 1904, this code was by authority of the President of the United States withdrawn it provided the starting-point of a movement for codification of maritime International Law. No complete Naval War Code agreed upon by the Powers has as yet made its appearance, but the second Hague Peace Conference of 1907 and the Naval Conference of London of 1908-9 have produced a number of law-making treaties which represent codifications of several parts of maritime International Law.

The second Hague Peace Conference met in 1907 and produced not less than thirteen conventions and one declaration. This declaration prohibits the discharge of projectiles and explosives from balloons and takes the place of a corresponding declaration of the first Hague Peace Conference. And three of the thirteen conventions, namely that for the pacific settlement of international disputes, that concerning the laws and customs of war on land, and that concerning the adaptation of the principles of the Geneva Convention to maritime war, likewise take the place of three corresponding conventions of the first Hague Peace Conference. But the other ten conventions are entirely new and concern: the limitation of the employment of force for the recovery of contract debts, the opening of hostilities, the rights and duties of neutral Powers and persons in war on land, the status of enemy merchant ships at the outbreak of hostilities, the conversion of merchant ships into war ships, the laying of automatic submarine contact mines, bombardments by naval forces in time of war, restrictions on the exercise of the right of capture in maritime war, the establishment of a Prize Court, the rights and duties of neutral Powers in maritime war.

The Naval Conference of London which met in November 1908, and sat till February 1909, produced the Declaration of London, the most important law-making treaty as yet concluded. Its nine chapters deal with: blockade, contraband, unneutral service, destruction of neutral prizes, transfer to a neutral flag, enemy character, convoy, resistance to search, compensation. The Declaration of London, when ratified, will make the establishment of an International Prize Court possible.