except between those who voluntarily submit to it by tacit convention" (p).

The public jurists of the school of Puffendorf had considered the science of international law as a branch of the science of ethics. They had considered it as the natural law of individuals applied to regulate the conduct of independent societies of men, called States. To Wolf belongs, according to Vattel, the credit of separating the law of nations from that part of natural jurisprudence which treats of the duties of individuals.

In the preface of his great work, he says, "That since such is the condition of mankind that the strict law of nature cannot always be applied to the government of a particular community, but it becomes necessary to resort to laws of positive institution more or less varying from the natural law, so in the great society of nations it becomes necessary to establish a law of positive institution more or less varying from the natural law of nations. As the common welfare of nations requires this mutation, they are not less bound to submit to the law which flows from it than they are bound to submit to the natural law itself, and the new law thus introduced, so far as it does not conflict with the natural law, ought to be considered as the common law of all nations. This law we have deemed proper to term, with Grotius, though in a somewhat stricter sense, the voluntary Law of Nations" (q).

Wolf afterwards says, that "the voluntary law of nations derives its force from the presumed consent of nations, the conventional from their express consent; and the consuetudinary from their tacit consent " (r).

This presumed consent of nations (consentium gentium præsumptum) to the voluntary law of nations he derives from the fiction of a great commonwealth of nations (civitate gentium maxima) instituted by nature herself, and of which all the nations of the world are members. As each separate society of men is governed by its peculiar laws freely adopted by itself, so is the general society of

§ 6.

(p) De Foro Legatorum, cap. xix.

(2) Wolfius, Jus Gentium, Pref. § 3. (r) Wolfius, Proleg. § 25.

nations governed by its appropriate laws freely adopted Chap. I. by the several members, on their entering the same. These laws he deduces from a modification of the natural law, so as to adapt it to the peculiar nature of that social union, which, according to him, makes it the duty of all nations to submit to the rules by which that union is governed, in the same manner as individuals are bound to submit to the laws of the particular community of which they are members. But he takes no pains to prove the existence of any such social union or universal republic of nations, or to show when and how all the human race became members of this union or citizens of

this republic.

§ 8. Wolf differs from Grotius, as to the origin of the Differences of voluntary law of nations, in two particulars:

opinion

between Grotius and

voluntary

Law of

Nations.

1. Grotius considers it as a law of positive institution, Wolf on the and rests its obligation upon the general consent of origin of the nations, as evidenced in their practice. Wolf, on the other hand, considers it as a law which nature has imposed upon all mankind as a necessary consequence of their social union; and to which no one nation is at liberty to refuse its assent.

2. Grotius confounds the voluntary law of nations with the customary law of nations. Wolf maintains that it differs in this respect, that the voluntary law of nations is of universal obligation, whilst the customary law of nations merely prevails between particular nations, among whom it has been established from long usage and tacit consent.

Vattel.

$9. It is from the work of Wolf that Vattel has drawn the System of materials of his treatise on the law of nations. He, however, differs from that publicist in the manner of establishing the foundations of the voluntary law of nations. Wolf deduces the obligations of this law, as we have already seen, from the fiction of a great republic instituted by nature herself, and of which all the nations of the world are members. According to him the voluntary law of nations is, as it were, the civil law of that great republic. This idea does not satisfy

Part I.

Vattel. "I do not find," says he, "the fiction of such a republic either very just or sufficiently solid to deduce from it the rules of a universal law of nations, necessarily admitted among sovereign States. I do not recognise any other natural society between nations than that which nature has established between all men. It is the essence of all civil society (civitatis), that each member thereof should have given up a part of his rights to the body of the society, and that there should exist a supreme authority capable of commanding all the members, of giving to them laws, and of punishing those who refuse to obey. Nothing like this can be conceived or supposed to exist between nations. Each sovereign State pretends to be, and in fact is, independent of all others. Even according to Mr. Wolf, they must all be considered as so many free individuals, who live together in a state of nature and acknowledge no other law than that of nature itself, and its Divine Author "(s).

According to Vattel, the Law of Nations, in its origin, is nothing but the law of nature applied to nations.

Having laid down this axiom, he qualifies it in the same manner, and almost in the identical terms of Wolf, by stating that the nature of the subject to which it is applied, being different, the law which regulates the conduct of individuals must necessarily be modified in its application to the collective societies of men called nations or States. A State is a very different subject from a human individual, from whence it results that the obligations and rights, in the two cases, are very different. The same general rule, applied to two subjects, cannot produce the same decisions when the subjects themselves differ. There are, consequently, many

cases in which the natural law does not furnish the same rule of decision between State and State as would be applicable between individual and individual. It is the art of accommodating this application to the different

(s) Vattel, Droit des Gens, Préface.

nature of the subjects in a just manner, according to right reason, which constitutes the law of nations a particular science.

This application of the natural law, to regulate the conduct of nations in their intercourse with each other, constitutes what both Wolf and Vattel term the necessary law of nations. It is necessary, because nations are absolutely bound to observe it. The precepts of the natural law are equally binding upon States as upon individuals, since States are composed of men, and since the natural law binds all men, in whatever relation they may stand to each other. This is the law which Grotius and his followers call the internal law of nations, as it is obligatory upon nations in point of conscience. Others term it the natural law of nations. This law is immutable, as it consists in the application to States of the natural law, which is itself immutable, because founded on the nature of things, and especially on the nature of

man.

This law being immutable, and the law which it imposes necessary and indispensable, nations can neither make any changes in it by their conventions, dispense with it in their own conduct, nor reciprocally release each other from the observance of it (t).

Vattel has himself anticipated one objection to his doctrine that States cannot change the necessary law of nations by their conventions with each other. This objection is, that it would be inconsistent with the liberty and independence of a nation to allow to others the right of determining whether its conduct was or was not conformable to the necessary law of nations. He obviates the objection by a distinction which pronounces treaties made in contravention of the necessary law of nations, to be invalid, according to the internal law, or that of conscience, at the same time that they may be valid by the external law; States being often obliged to acquiesce in such deviations from the former

(t) Droit des Gens, Préliminaires, §§ vi. vii. viii. ix,

Chap. I.

Part I. law in cases where they do not affect their perfect

rights (u).

From this distinction of Vattel, flows what Wolf had denominated the voluntary law of nations, (jus gentium voluntarium,) to which term his disciple assents, although he differs from Wolf as to the manner of establishing its obligation. He, however, agrees with Wolf in considering the voluntary law of nations as a positive law, derived from the presumed or tacit consent of nations to consider each other as perfectly free, independent, and equal, each being the judge of its own actions, and responsible to no superior but the Supreme Ruler of the universe.

Besides this voluntary law of nations, these writers enumerate two other species of international law. These

are:

1. The conventional law of nations, resulting from compacts between particular States. As a treaty binds only the contracting parties, it is evident that the conventional law of nations is not a universal, but a particular law.

2. The customary law of nations, resulting from usage between particular nations. This law is not universal, but binding upon those States only which have given their tacit consent to it.

Vattel concludes that these three species of international law, the voluntary, the conventional, and the customary, compose together the positive law of nations. They proceed from the will of nations; or (in the words of Wolf) "the voluntary, from their presumed consent; the conventional, from their express consent; and the customary, from their tacit consent " (x).

It is almost superfluous to point out the confusion in this enumeration of the different species of international law, which might easily have been avoided by reserving the expression "voluntary law of nations," to designate the genus, including all the rules introduced by positive

(u) Droit des Gens, Préliminaires, § ix.

(x) Droit des Gens, Préliminaires, xxvii.; Wolf, Proleg. § xxv.