torious nations to give a price for territory acquired in war, as when the United States paid a sum of money to Mexico for lands ceded at the peace of 1848.*

states, or duties

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Moral claims and duties being to a great extent determined Moral relations of by the special circumstances of the case, cannot and moral claims. be so easily defined and enforced as rights and obligations; and opinions in regard to them vary with the varying moral feelings of individuals, of countries and of ages. Hence, with the increase of culture, and the greater sway of pure religion, the influence of moral ideas over nations enlarges. No cause has had greater efficacy in producing changes in international law than this, of which the improvements in the laws of war, and in the treatment of individuals out of their own country, are good illustrations. The rules drawn from this source are less capable of being reduced to a theory than those deducible from jural relations.

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One or two recognized branches of duty between nations deserve a brief notice.

Particular duties. 1. Humanity.

1. The duty of humanity, including hospitality. This duty spends itself chiefly in the treatment of individuals, although suffering nations or parts of nations may also call for its exercise. The awakened sentiment of

* The Abbé de Mably, on this subject, uses the following language: "A prince is doubtless in the right in conquering a province which belongs to him, and of which the restitution is refused. He can, even, to punish his enemy for his injustice and to recompense himself for the expenses of war which he has been forced to make, extend his conquests beyond the country which he claims as his own. But arms, of themselves, give no title; they suppose an anterior one, and it is to try this contested right that the war is waged. Were it otherwise, a prince despoiled by his enemy, would no longer have any right to the countries which have been taken from him, and hence it would be ridiculous for the victor to demand a cession from him in treaties of peace. We may add here a very simple argument; if conquests by their nature form a legitimate right of possession to the conqueror, it is indifferent whether the war be undertaken on just or unjust grounds." Droit public, vol. I. part 2, 109, ed. of Amsterdam of 1777.

humanity in modern times is manifested in a variety of ways, as by efforts to suppress the slave trade, by greater care for captives, by protection of the inhabitants of a country from invading armies, by the facility of removing into a new country, by the greater security of strangers. Formerly, the individual was treated as a part of the nation on whom its wrongs might be wreaked. Now this spirit of war against private individuals is passing away. In general, any decided want of humanity arouses the indignation even of third parties, excites remonstrances, and may call for interposition. (Comp. § 21, § 50.) But cruelty may also reach beyond the sphere of humanity; it may violate right, and justify self-protection and resistance.

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2. Comity.

Comity is another duty of nations. To this source may be referred in part the privileges conceded to ambassadors, and the preference given in certain cases to foreign over domestic law by the courts of Christendom. Comity, as generally understood, is national politeness and kindness. But the term seems to embrace not only that kindness which emanates from friendly feeling, but also those tokens of respect which are due between nations on the ground of right. ·

A much wider sense is given to the term comity by those who embrace in it all those praiseworthy acts of one nation towards another, which are not stricti juris, that is, all that, the refusal or withholding of which, although dictated by malevolence, is not an injury, and so not a ground for war. But usages originating in comity may become rights by lapse of time. (Comp. Phillimore, I. 161, and §§ 26, 28, infra.)

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3. Intercourse.

Some have contended that there is a positive obligation on nations to enter into relations at least of commerce, so that the refusal thus to act would be an injury, and possibly a cause of war. It might be said that differences of climate, soil, productions, and acquired skill, enable

all parts of the world to aid one another, and that this clearly points out a divine destination and intention that they shall so act. But the better opinion is, that, except in extreme cases,

as when one nation cannot do without the productions of another, or must cross its borders to get at the rest of the world -this is only a duty, an exercise of a spirit of goodwill, to be judged of by each state according to the light which it possesses. In all intercourse the two parties concerned must settle the terms; how then can one force the other into a treaty of commerce, any more than one man force another into a contract.

But although writers are believed to agree substantially in this, there is a disposition on the part of nations to act as if they had a right to require others to exchange products with them. This has been seen in the dealings of later years with certain Oriental and other states. But might not one Christian state with greater reason force another to give up its protective tariff?

It thus appears that intercourse, which is a preliminary to all international law, and the condition, without which rights and obligations would be mere abstract conceptions, is itself referable to the class of duties, and that the refusal to allow it is no injury. There is nothing more strange in this than in the voluntariness of all private contracts, as of the marriage union, which must be presupposed before any family rights can exist. All that rights serve for is, when intercourse is given, to make it jural. Thus we see again the voluntary quality of international law.

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Vattel divides the law of nations into the natural or necesVattel's divisions sary, so called because nations are absolutely of intern. law. obliged to observe it; and the positive, proceeding from the volition of nations. This latter, again, is subdivided into voluntary, conventional, and customary law, which are respectively derived from presumed, expressed, and tacit consent. Of voluntary law Vattel says, that it embraces the rules drawn from the principle that nations, being equal

and independent, are obliged to suffer each other to do many blamable things, presuming or acting as if they were right. Thus capture in war is valid, whether made by the aggressor or the injured. But there seems to be no reason for setting off this as a distinct branch, and it is by no means clearly defined. Such cases as Vattel contemplates are to be referred to the obligation under which nations lie of not interfering with each other's sovereignty, and thus run back to the necessary law of nations.

Dr. Wheaton, justly discarding this subordinate division of voluntary law, makes natural law one genus, and Wheaton's. voluntary, another, under which latter conventional and customary are included. The division of interna tional law into primitive and secondary law, is altogether similar to this, primitive being the law of nature and secondary that of treaty and usage. But these divisions, although avoiding Vattel's error, are of no great value. For, (1.) A requirement of natural law may be confirmed by voluntary, as by a treaty: to which, then, of the two does it belong? (2.) Conventional law hitherto includes no treaties between all the Christian states of the world, and thus is rather to be taken as evidence of what international law is, than as a part of it. Nay, treaties are often made to except the parties from the operation of a real or supposed international rule. (3.) In reality all international law is voluntary, not in the sense that it derives its sole obligation from the will of the parties, but in the sense that all nations in a certain circle agree to abide by it. (4.) And again, all voluntary law is natural, being built on the foundation of the sacredness of agreements.

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Perhaps a division like the following may have something to commend it, which separates the rights and Other divisions. obligations known to this science into, (1.) those

which are deducible from natural jus, which no action of a sovereignty began or can terminate; (2.) those deducible from the idea of a state; (3.) those which are begun and can be

ended by compact, express or tacit. Another division still, which we have made already (§ 2), follows the division of the three grounds or reasons for international rules, namely, jus, morality, and convenience. The first class comprehends natural rights and obligations, which can be defined and enforced; the second, duties and moral claims which cannot be easily defined, and need compact to establish them; and the third, arrangements of a purely voluntary nature. A very considerable part of international law is included under the second and third of these heads; a fact which serves to show the highly positive or voluntary nature of much of the science. Thus exterritoriality, private international law, the rules of respect, some, at least, of the regulations touching ambassadors, the laws of war to a great extent, and, indeed, much else is of this description. These parts of the science cannot be deduced from a theory, nor could they have arisen prior to a long experience. $ 28.

consent alike

Whether the free assent of nations take the form of express Custom and free agreement or of usage, it places them alike under sources of law. ♦the obligation of contract. Customs within each country existed before statutes, and so observances come in imperceptibly and control the conduct of a circle of nations. A nation which grants privileges to another by tacit consent, and then revokes them without cause, may commit an injury just as if it had broken a treaty. For example, intercourse may become a right by becoming a fact, and to end it would be a proof of a hostile mind.

It is to be remarked, also, that not only obligations of natural justice are recognized in this tacit way, but duties become obligations, and claims or conveniences, allowed, become rights, just as by formal contract. A nation may grant the privilege of transit to the troops of another by treaty; it has now become a right. The same thing may come about by custom or tacit consent. It might seem as if nations could alter their conduct at pleasure, within the spheres of moral claims and convenience. But if they have sanctioned a usage by long permission without protest, they have laid an obliga