The sources of international law, that is, the places where the principles and rules governing the conduct of States first appear as such, as distinct from the causes responsible for that law and the evidence of what it is, are deemed to be primarily, custom, and secondarily, certain agreements or treaties.1 Few treaties are to be regarded as sources of international law, because, apart from the design of the contracting parties, the provisions of such compacts infrequently give expression to new rules of conduct which, through their reasonableness and general responsiveness to the needs of the international society, win its full approval. Some agreements have, however, been so operative, serving to register not only the views of the contracting parties, but also the beginnings of rules of restraint which ultimately met with general acquiescence.

Custom as a source of international law must not be confounded, as Westlake has observed, "with mere frequency or habit of conduct." It signifies rather "that line of conduct which the society has consented to regard as obligatory." In such a sense international custom is indicative of a general practice which may be fairly accepted as law.3

2

The evidence of international law is to be found in many places. A variety of acts and documents bear testimony as to the principles which are deemed actually to govern the conduct of States. The views of text-writers or commentators are oftentimes cited as authoritative. The Supreme Court of the United States has observed, however, that "such works are resorted to by judicial tribunals, not for the speculation of their authors concerning what the law ought to be, but for trustworthy evidence of what the law really is." Whenever such writers do not evince a disposi

4

1 Frantz Despagnet, Cours de Droit International Public, 4 ed., §§ 55-60; Bonfils-Fauchille, 7 ed., § 46; Oppenheim, 2 ed., I, § 16.

2 Westlake, I, 2 ed., 14, where it is added: "In any state or other society in which customary law is admitted, custom as a part of law means the conduct which is enforced as well as the strict or loose nature of the society allows

not always very well, as in the case of national law, in the ruder stages of national existence and which is followed as well from the fear of such enforcement as from the persuasion that the received rule requires such conduct to be followed."

3 See Art. XXXV, Section 2, of Draft-Scheme for the institution of the Permanent Court of International Justice, presented to the Council of the League of Nations by the Advisory Committee of Jurists, and communicated by the League to numerous States August 27, 1920.

4 Mr. Justice Gray, in the opinion of the Court, in The Paquete Habana, 175 U. S. 677, 700.

According to Art. XXXV of the Draft-Scheme for the institution of the

tion to mirror the practice of their time, the views expressed lack evidential value.1

Doubtless some treaties afford evidence of international law. Those which, for example, purport to enunciate general rules of conduct, to which substantially all enlightened States consent, embracing those which have not formally adhered to the arrangements, are of such a kind. Certain conventions of the Hague Peace Conferences of 1899 and 1907 may be deemed to fulfill such a function.

Official acts or declarations of individual States are at times referred to as evidence of international law. They may serve to indicate the understanding of the governments thereof with respect to the nature and scope of particular rights and obligations. The diplomatic correspondence of the United States has oftentimes revealed the precise views of those in charge of its foreign relations touching the requirements of the law of nations. Enunciations of legal principle emanating from the Department of State are to be respected when they purport to express what the United States officially declares to be the general usage or practice establishing Permanent Court of International Justice, communicated by the Council of the League of Nations, August 27, 1920, "the teachings of the most highly qualified publicists of the various nations" were declared to be "subsidiary means for the determination of .rules of law."

1 The inclination of distinguished scholars to heed the views of other theorists rather than those upon which States act from a sense of legal obligation, tends in certain countries to weaken the respect entertained for treatises purporting to be declaratory of international law, because doubt is felt whether the authors have in fact made serious attempt to bear witness to the rules actually governing the relations of independent States.

See Lord Alverstone, C. J., in West Rand Central Gold Mining Co. v. The King [1905] 2 K. B. 391; Evans, Cases, 15.

"There is no doubt that, when all or most of the great Powers have deliberately agreed to certain rules of general application, the rules approved by them have very great weight in practice even among States which have never expressly consented to them. It is hardly too much to say that declarations of this kind may be expected, in the absence of prompt and effective dissent by some Power of the first rank; to become part of the universally received law of nations within a moderate time. As among men, so among nations, the opinions and usage of the leading members in a community tend to form an authoritative example for the whole. A striking proof of this tendency was given in the war of 1898 between Spain and the United States. Neither belligerent was a party to the article of the Declaration of Paris of 1856 against privateering; the United States had in fact refused to join in it. Moreover, the Declaration of Paris was not, in point of form, an instrument of the highest authority. Nevertheless, when the war of 1898 broke out, the United States proclaimed its intention of adhering to the Declaration of Paris, and the rules thereby laid down were in fact observed by both belligerents. It is quite possible that some of the recommendations recorded at the Peace Conference at the Hague in 1899, may sooner or later, in like manner, be adopted as part of the public law of civilized nations by general recognition without any formal ratification." Sir Frederick Pollock, in Columbia Law Rev., II, 511, 512.

the rule of international law.1 American state papers have from time to time shed much light because they have embodied the testimony of witnesses zealous for the truth and sensitive to injustice. Notwithstanding occasional yieldings to the temptation to assert in diplomatic discussions pretensions at variance with accepted principle, as by way of defense of conduct denounced by a foreign power, the United States has throughout its experience manifested strongest disposition to observe and inculcate respect for international justice. Its Constitution, its statutory laws, its diplomatic correspondence, the codifications of its army and navy, as well as the decisions of its courts, afford abundant illustration. For that reason the views of American statesmen have been heeded by the outside world and still exert a corresponding influence. The testimony borne by the United States deserves scrutiny because it has proved worthy of acceptation.

The decisions of local tribunals oftentimes afford evidence of international law. Those of American courts, both Federal and State, abound in opinions manifesting a careful and impartial effort to enunciate the principles observed by civilized States. The decisions of the prize courts of a belligerent are oftentimes commended as entitled to special authority because of the function of such tribunals to determine, according to the requirements of international law, the propriety of acts of capture and others

1 It is not suggested that interpretations of international law given by those responsible for the conduct of the foreign relations of the United States are invariably sound, or ever above criticism when shown to be at variance with the principles generally obtaining among enlightened States. Such interpretations, whether sound or unsound, deserve close attention because, with respect to the principle or rule involved, they are, in a sense, the views of the nation, and as such attain larger international significance than those expressed unofficially by private individuals, at least as evidence of requirements recognized in fact by the society of nations. In a word, if the propriety of national conduct is to be tested according to principles and rules which States observe in practice from a sense of legal obligation, the views of the Department of State as to the requirements of that practice are believed to be entitled to great respect, and to closer consideration than the utterances of writers whose purpose is rather to emphasize what, in their judgment, and regardless of current practice, the law of nations ought to be.

2 "Founded upon the idea of law, and existing under the protection of law, the United States of America, more perhaps than any other sovereign power, has aimed to establish its relations with other governments on the basis of law; and has instinctively shrunk from extending them, even when provoked by the turbulence and insolence of comparatively impotent neighbors, on a basis of preponderant power. In all the international councils in which we have as a nation hitherto participated, our government has endeavored to establish law as a standard for the conduct of sovereign states. Being itself a creation of law, it has appeared natural to base its foreign relations upon it." David Jayne Hill, "The Nations and the Law", Reports of American Bar Association, 1919, XLIV, 171, 179.

incidental thereto.1 It has been found, however, that even when not restrained by the tenor of local statutory or other regulations, the natural prejudices of the most enlightened and scrupulous tribunal established under belligerent authority tend to weaken its impartiality and to diminish foreign respect for its conclusions.2 Awards of international tribunals such as courts of arbitration possessed of a neutral empire (if not of entire neutral membership) afford impressive evidence of the requirements of international law. The impartiality and acumen revealed by the neutral members of such bodies have oftentimes been productive of decisions entitled to great respect by States generally. This has been notably true in the case of the awards of the Court of Arbitration organized in pursuance of the Hague Conventions of 1899 and 1907. Those to be rendered by the Permanent Court of International Justice (of which the establishment is anticipated at an early date) will doubtless serve from time to time increasingly to bear testimony of the highest order as to what the law of nations really is.*

§ 4. Absence of a Legal Sanction.

The domestic laws of a State are commonly enforced by the territorial sovereign. There is a sanction which, although not essential to the existence of the law, is of a strictly legal character, inasmuch as it is established and applied by the lawgiver, and because in theory it is enforced only when a legal duty has been violated, and with close regard for the extent of the harm publicly or privately sustained.

With respect to international law the situation is otherwise. Doubtless the society of civilized States approves of the enforcement of the rules of that law by appropriate means, and by various processes. It does not, however, as yet prescribe the procedure to be followed by an aggrieved State, nor even enjoin, under certain conditions, recourse to war. Powerful forces, nevertheless,

1 Dana's Wheaton, Dana's Note No. 11. In this connection, see judgment by Lord Parker of Waddington in The Zamora [1916], 2 A. C. 77; 4 Lloyd's Prize Cases, 84.

2 See Discussion between United States and Great Britain during The World War, §§ 894-895.

3 See, for example, the award in the Pious Fund Case between the United States and Mexico, Oct. 14, 1902, For. Rel. 1902, Appendix II, 15; J. B. Scott, Hague Court Reports, 3; also award in the North Atlantic Coast Fisheries Arbitration between the United States and Great Britain, Sept. 7, 1910, Proceedings, North Atlantic Coast Fisheries Arbitration, Senate Doc. No. 870, 61 Cong., 3 Sess., I, 103; J. B. Scott, Hague Court Reports, 146. See Permanent Court of International Justice Designed by Advisory Committee of Jurists, 1920, infra, §§ 573–576.

unceasingly operate to produce respect for international law. There is, as Mr. Elihu Root has pointed out, "an indefinite a:. almost mysterious influence exercised by the general opinion of the world" regarding the character and conduct of every State. "The greatest and strongest governments recognize this 'influence and act with reference to it; they dread the moral isolation that accompanies it and they desire general approval and the kindly feeling that goes with it." Again, the fear of war also serves frequently to restrain States from violating international obligations. A weak State, however strongly inclined to disregard a legal duty with respect to a powerful neighbor, is reluctant to test its strength on unequal terms with such an adversary. Nevertheless, it should be observed that a weak State may, on the other hand, anticipate with certainty that its adherence to a lawful and commendable course which opposes the designs of an unscrupulous and stronger State will invite attack upon its own domain. Thus if war ensues because of the breach of international law, or because of fidelity to the principles of that law, the consequences may prove to be in fact identical. For that reason the fear of war, which may serve in a particular case to encourage disregard of an international duty as well as respect for it, is not · to be deemed a sanction possessed of a legal character.3

2

Although without what may fairly be described as a legal sanction, the principles and rules governing the conduct of States do not lack the quality of law. It is no longer seriously maintained

1 "The Sanction of International Law", Proceedings, American Soc. Int. Law, II, 14, 19-20, where it is added: "The real sanction which enforces those rules is the injury which inevitably follows nonconformity to public opinion; while, for the occasional and violent or persistent lawbreaker, there always stands behind discussion the ultimate possibility of war, as the sheriff and the policeman await the occasional and comparatively rare violators of municipal law."

2 Belgium was confronted with such a difficulty in 1914. It was given sharp warning that attempts to maintain the inviolability of its territory against Germany would subject that territory to the full opposition of German belligerent force.

It is not suggested that the fear of war is as strong or frequent an incentive to violations of international law as to acts in pursuance thereof. It seems necessary to observe, however, that the fear of measures which may be undertaken to thwart lawful as well as unlawful conduct, and by a State controlled by conscienceless rulers, with an unjust purpose, cannot be regarded as an agency of the law designed to enforce respect for its precepts.

"The sanction of public opinion, if such there be, attaches equally to principles of purely moral obligation; to identify such a sanction with the sanction of law is to sacrifice the distinction between positive law and ideal morality. War as a sanction is analogous to the act of an individual in a community in enforcing his rights by brute force." Note, Harvard Law Rev., XVIII, 476.

See also Bonfils-Fauchille, 7 ed., § 29; Pradier-Fodéré, I, § 23, p. 77.