The Law of Nations or the Principles of Natural Law (1758)

Emmerich de Vattel

Of Securities Given for the Observance of Treaties

§ 235. Guaranty.
CONVINCED by unhappy experience, that the faith of treaties, sacred and inviolable as it ought to be, does not always afford a sufficient assurance that they shall be punctually observed, — mankind have sought for securities against perfidy, — for methods, whose efficacy should not depend on the good faith of the contracting parties. A guaranty is one of these means. When those who make a treaty of peace, or any other treaty, are not perfectly easy with respect to its observance, they require the guaranty of a powerful sovereign. The guarantee promises to maintain the conditions of the treaty, and to cause it to be observed. As he may find himself obliged to make use of force against the party who attempts to violate his promises, it is an engagement that no sovereign ought to enter into lightly, and without good reason. Princes indeed seldom enter into it unless when they have an indirect interest in the observance of the treaty, or are induced by particular relations of friendship. The guaranty may be promised equally to all the contracting parties, to some of them, or even to one alone; but it is commonly promised to all in general. It may also happen, when several sovereigns enter into a common alliance, that they all reciprocally pledge themselves to each other as guarantees for its observance. The guaranty is a kind of treaty, by which assistance and succors are promised to any one, in case he has need of them, in order to compel a faithless ally to fulfill his engagements.

§ 236. It gives the guarantee no right to interfere unasked in the execution of a treaty.
Guaranty being given in favor of the contracting powers, or one of them, it does not authorize the guarantee to interfere in the execution of the treaty, or to enforce the observance of it, unasked, and of his own accord. If, by mutual consent, the parties think proper to deviate from the tenor of the treaty, to alter some of the articles, or to cancel it altogether, — or if one party be willing to favor the other by a relaxation of any claim, — they have a right to do this and the guarantee cannot oppose it. Simply bound by his promise to support the party who should have reason to complain of the infraction of the treaty, he has acquired no rights for himself. The treaty was not made for him; for, had that been the case, he would have been concerned, not merely as a guarantee, but as a principal in the contract. This observation is of great importance: for care should be taken, lest, under color of being a guarantee, a powerful sovereign should render himself the arbiter of the affairs of his neighbors, and pretend to give them law.

But it is true, that, if the parties make any change in the articles of the treaty without the consent and concurrence of the guarantee, the latter is no longer bound to adhere to the guaranty; for the treaty thus changed is no longer that which he guarantied.1

§ 237. Nature of the obligation it imposes.
As no nation is obliged to do any thing for another nation, which that other is herself capable of doing, it naturally follows that the guarantee is not bound to give his assistance except where the party to whom he has granted his guaranty is of himself unable to obtain justice.

If there arises any dispute between the contracting parties respecting the sense of any article of the treaty, the guarantee is not immediately obliged to assist him in favor of whom he has given his guaranty. As he cannot engage to support injustice, he is to examine, and to search for the true sense of the treaty, to weigh the pretensions of him who claims his guaranty; and, if he finds them ill founded, he may refuse to support them, without failing in his engagements.

§ 238. The guaranty cannot impair the rights of a third party.
It is no less evident that the guaranty cannot impair the rights of any one who is not a party to the treaty. If, therefore, it happens that the guarantied treaty proves derogatory to the rights of those who are not concerned in it, — the treaty being unjust in this point, the guarantee is in no wise bound to procure the performance of it; for, as we have shown above, he can never have incurred an obligation to support injustice. This was the reason alleged by France, when, notwithstanding her having guarantied the famous pragmatic sanction of Charles VI., she declared for the house of Bavaria, in opposition to the heiress of that emperor. This reason is incontestably a good one, in the general view of it: and the only question to be decided at that time was, whether the court of France made a just application of it.

Non nostrum vos tantas componere lites.

I shall observe on this occasion, that, according to common usage, the term guaranty is often taken in a sense somewhat different from that we have given to it. For instance, most of the powers of Europe guarantied the act by which Charles VI, had regulated the succession to his dominions; — sovereigns sometimes reciprocally guaranty their respective states. But we should rather denominate those transactions treaties of alliance, for the purpose, in the former case, of maintaining that rule of succession. — and, in the latter, of supporting the possession of those states.

§ 239. Duration of the guaranty.
The guaranty naturally subsists as long as the treaty that is the object of it; and, in case of doubt, this ought always to be presumed, since it is required, and given, for the security of the treaty. But there is no reason which can naturally prevent its limitation to a certain period, — to the lives of the contracting powers, to that of the guarantee, etc. In a word, whatever we have said of treaties in general is equally applicable to a treaty of guaranty.

§ 240. Treaties with surety.
When there is question of things which another may do or give as well as he who promises, as, for instance, the payment of a sum of money, it is safer to demand a security than a guaranty: for the surety is bound to make good the promise in default of the principal, — whereas the guarantee is only obliged to use his best endeavors to obtain a performance of the promise from him who has made it.

§ 241. Pawns, securities, and mortgages.
A nation may put some of her possessions into the hands of another, for the security of her promises, debts, or engagements. If she thus deposits movable property, she gives pledges. Poland formerly pledged a crown and other jewels to the sovereigns of Prussia. But sometimes towns and provinces are given in pawn. If they are only pledged by a deed which assigns them as security for a debt, they serve as a mortgage: if they are actually put into the hands of the creditor, or of him with whom the affair has been transacted, he holds them as pledges: and, if the revenues are ceded to him as an equivalent for the interest of the debt, the transaction is called a compact of antichresis.

§ 242. A nation’s right over what she holds as a pledge.
The right which the possession of a town or province confers upon him who holds it in pledge, extends no further than to secure the payment of what is due to him, or the performance of the promise that has been made to him. He may therefore retain the town or the province in his hands, till he is satisfied: but he has no right to make any change in it; for that town, or that country, does not belong to him as proprietor. He cannot even interfere in the government of it, beyond what is required for his own security, unless the empire, or the exercise of sovereignty, has been expressly made over to him. This last point is not naturally to be presumed, since it is sufficient for the security of the mortgagee, that the country is put into his hands and under his power. Further, he is obliged, like every other person who has received a pledge, to preserve the country he holds as a security, and, as far as in his power, to prevent its suffering any damage or dilapidation: he is responsible for it; and if the country is ruined through his fault, he is bound to indemnify the state that intrusted him with the possession of it. If the sovereignty is deposited in his hands together with the country itself, he ought to govern it according to its constitution and precisely in the same manner as the sovereign of the country was obliged to govern it; for the latter could only pledge his lawful right.

§ 243. How she is obliged to restore it.
As soon as the debt is paid, or the treaty is fulfilled, the term of the security expires, and he who holds a town or a province by this title is bound to restore it faithfully, in the same state in which he received it, so far as this depends on him.

But to those who have no law but their avarice, or their ambition — who, like Achilles, place all their right in the point of their sword2 — a tempting allurement now presents itself: they have recourse to a thousand quibbles, a thousand pretenses, to retain an important place, or a country which is conveniently situated for their purposes. The subject is too odious for us to allege examples: they are well enough known, and sufficiently numerous to convince every sensible nation, that it is very imprudent to make over such securities.

§ 244. How she may appropriate it to herself.
But if the debt be not paid at the appointed time, or if the treaty be not fulfilled, what has been given in security may be retained and appropriated, or the mortgage seized, at least until the debt is discharged, or a just compensation made.

The house of Savoy had mortgaged the country of Faud to the cantons of Bern and Fribourg; and those two cantons, finding that no payments were made, had recourse to arms, and took possession of the country. The duke of Savoy, instead of immediately satisfying their just demands, opposed force to force, and gave them still further grounds of complaint: wherefore the cantons, finally successful in the contest, have since retained possession of that fine country, as well for the payment of the debt, as to defray the expenses of the war, and to obtain a just indemnification.

§ 245. Hostages.
Finally, there is, in the way of security, another precaution, of very ancient institution, and much used among nations — which is, to require hostages. These are persons of consequence, delivered up by the promising party, to him with whom he enters into an engagement, to be detained by the latter until the performance of the promises which are made to him. In this case, as well as in those above mentioned, the transaction is a pignorary contract, in which free men are delivered up, instead of towns, countries, or jewels. With respect to this contract, therefore, we may confine ourselves to those particular observations which the difference of the things pledged renders necessary.

§ 246. What right we have over hostages.
The sovereign who receives hostages has no other right over them than that of securing their persons, in order to detain them till the entire accomplishment of the promises of which they are the pledge. He may therefore take precautions to prevent their escaping from him: but those precautions should be moderated by humanity towards men whom he has no right to use ill; and they ought not to be extended beyond what prudence requires.

It is pleasing to behold the European nations in the present age content themselves with the bare parol of their hostages. The English noblemen who were sent to France in that character, in pursuance of the treaty of Aix-la-Chapelle, in 1748, to stay till the restitution of Cape Breton, were solely bound by their word of honor, and lived at court, and at Paris, rather as ministers of their nation than as hostages.

§ 247. Their liberty alone is pledged.
The liberty of the hostages is the only thing pledged: and if he who has given them breaks his promise, they may be detained in captivity. Formerly they were in such cases put to death; — an inhuman cruelly, founded on an error. It was imagined that the sovereign might arbitrarily dispose of the lives of his subjects, or that every man was the master of his own life, and had a right to stake it as a pledge when he delivered himself up as hostage.

§ 248. When they are to be sent back.
As soon as the engagements are fulfilled, the cause for which the hostages were delivered no longer subsists: they then immediately become free, and ought to be restored without delay. They ought also to be restored, if the reason for which they were demanded does not take place: to detain them then would be to abuse the sacred faith upon which they are delivered. The perfidious Christiern II., king of Denmark, being delayed by contrary winds before Stockholm, and, together with his whole fleet, ready to perish with famine, made proposals of peace: whereupon, the administrator, Steno, imprudently trusting to his promises, furnished the Danes with provisions, and even gave Gustavus and six other noblemen as hostages for the safety of the king, who pretended to have a desire to come on shore: but, with the first fair wind, Christiern weighed anchor, and carried off the hostages; thus repaying the generosity of his enemy by an infamous act of treachery.3

§ 249. Whether they may be detained on any other account.
Hostages being delivered on the faith of treaties, and he who receives them promising to restore them as soon as the promise of which they are the surety shall be fulfilled, — such engagements ought to be literally accomplished: and the hostages should be really and faithfully restored to their former condition, as soon as the accomplishment of the promise has disengaged them. It is, therefore, not allowable to detain them for any other cause; and I am astonished to find that some learned writers teach a contrary doctrine.4 They ground their opinion upon the principle which authorizes a sovereign to seize and detain the subjects of another state in order to compel their rulers to do him justice. The principle is true; but the application is not just. These authors seemed to have overlooked the circumstance, that, were it not for the faith of the treaty by virtue of which the hostage has been delivered, he would not be in the power of that sovereign, nor exposed to be so easily seized; and that the faith of such a treaty does not allow the sovereign to make any other use of his hostage than that for which he was intended, or take advantage of his detention beyond what has been expressly stipulated. The hostage is delivered for the security of a promise, and for that alone. As soon, therefore, as the promise is fulfilled, the hostage, as we have just observed, ought to be restored to his former condition. To tell him that he is released as a hostage, but detained as a pledge for the security of any other pretension, would be taking advantage of his situation as a hostage, in evident violation of the spirit and even the letter of the convention, according to which, as soon as the promise is accomplished, the hostage is to be restored to himself and his country, and reinstated in his pristine rank, as if he had never been a hostage. Without a rigid adherence to this principle, it would no longer be safe to give hostages, since princes might, on every occasion, easily devise some pretext for detaining them. Albert the Wise, duke of Austria, making war against the city of Zurich, in the year 1353, the two parties referred the decision of their disputes to arbitrators, and Zurich gave hostages. The arbitrators passed an unjust sentence, dictated by partiality. Zurich, nevertheless, after having made a well-grounded complaint on the subject, determined to submit to their decision. But the duke formed new pretensions, and detained the hostages,5 contrary to the faith of the compromise, and in evident contempt of the law of nations.

§ 250. They may be detained for their own actions.
But a hostage may be detained for his own actions, for crimes committed, or debts contracted in the country while he is in hostage there. This is no violation of the faith of the treaty. In order to be sure of recovering his liberty, according to the terms of the treaty, the hostage must not claim a right to commit, with impunity, any outrages against the nation by which he is kept; and when he is about to depart, it is just that he should pay his debts.

§ 251. Of the support of hostages.
It is the party who gives the hostages that is to provide for their support; for, it is by his order, and for his service, that they are in hostage. He who receives them for his own security is not bound to defray the expense of their subsistence, but simply that of their custody, if he thinks proper to set a guard over them.

§ 252. A subject cannot refuse to be a hostage.
The sovereign may dispose of his subjects for the service of the state; he may, therefore, give them also as hostages; and the person who is nominated for that purpose is bound to obey, as he is, on every other occasion, when commanded for the service of his country. But, as the expenses ought to be borne equally by the citizens, the hostage is entitled to be defrayed and indemnified at the public charge.

It is, evidently, a subject alone who can be given as a hostage against his will. With a vassal, the case is otherwise. What he owes to the sovereign, is determined by the conditions of his fief; and he is bound to nothing more. Accordingly, it is a decided point that a vassal cannot be constrained to go as a hostage, unless he be at the same time a subject.

Whoever has a power to make treaties or conventions, may give and receive hostages. For this reason, not only the sovereign, but also the subordinate authorities, have a right to give hostages in the agreements they make, according to the powers annexed to their office, and the extent of their commission. The governor of a town, and the besieging general, give and receive hostages for the security of the capitulation: whoever is under their command is bound to obey, if he is nominated for that purpose.

§ 253. Rank of the hostages.
Hostages ought naturally to be persons of consequence, since they are required as a security. Persons of mean condition would furnish but a feeble security, unless they were given in great numbers. Care is commonly taken to settle the rank of the hostages that are to be delivered; and the violation of a compact in this particular is a flagrant dereliction of good faith and honor. It was a shameful act of perfidy in La Trimouille to give the Swiss only hostages from the dregs of the people, instead of four of the principal citizens of Dijon, as had been stipulated in the famous treaty we mentioned above (§ 212). Sometimes the principal persons of the state, and even princes, are given in hostage, Francis I. gave his own sons as security for the treaty of Madrid.

§ 254. They ought not to make their escape.
The sovereign who gives hostages ought to act ingenuously in the affair, — giving them in reality as pledges of his word, and, consequently, with the intention that they should be kept till the entire accomplishment of his promise. He cannot, therefore, approve of their making their escape: and, if they take such a step, so far from harboring them, he is bound to send them back. The hostage, on his side, conformably to the presumed intention of his sovereign, ought faithfully to remain with him to whom he is delivered, without endeavoring to escape. Clœlia made her escape from the hands of Porsenna, to whom she had been delivered as a hostage; but the Romans sent her back, that they might not incur the guilt of violating the treaty.6

§ 255. Whether a hostage who dies is to be replaced.
If the hostage happens to die, he who has given him is not obliged to replace him, unless this was made a part of the agreement. The hostage was a security required of him: that security is lost without any fault on his side; and there exists no reason why he should be obliged to give another.

§ 256. Of him who takes the place of a hostage.
If any one substitutes himself for a time in the place of a hostage, and the hostage happens in the interim to die a natural death, the substitute is free: for, in this case, things are to be replaced in the same situation in which they would have been if the hostage had not been permitted to absent himself and substitute another in his stead: and, for the same reason, the hostage is not free by the death of him who has taken his place only for a time. It would be quite the contrary, if the hostage had been exchanged for another: the former would be absolutely free from all engagement; and the person who had taken his place would alone be bound.

§ 257. A hostage succeeding to the crown.
If a prince who has been given in hostage succeeds to the crown, he ought to be released on the delivery of another sufficient hostage, or a number of others, who shall together constitute an aggregate security equivalent to that which he himself afforded when he was originally given. This is evident from the treaty itself, which did not import that the king should be a hostage. The detention of the king’s person by a foreign power is a thing of too interesting a nature to admit a presumption that the state had intended to expose herself to the consequences of such an event. Good faith ought to preside in all conventions; and the manifest or justly presumed intention of the contracting parties ought to be adhered to. If Francis I. had died after having given his sons as hostages, certainly the dauphin should have been released: for, he had been delivered only with a view of restoring the king to his kingdom; and, if the emperor had detained him, that view would have been frustrated, since the king of France would still have been a captive. It is evident, that, in this reasoning, I proceed on the supposition that no violation of the treaty has taken place on the part of the state which has given a prince in hostage. In case that state had broken its promise, advantage might reasonably be taken of an event which rendered the hostage still more valuable, and his release the more necessary.

§ 258. The liability of the hostage ends with the treaty.
The liability of a hostage, as that of a city or a country, expires with the treaty which it was intended to secure (§§ 243, 248): and consequently, if the treaty is personal, the hostage is free at the moment when one of the contracting powers happens to die.

§ 259. The violation of the treaty is an injury done to the hostages.
The sovereign who breaks his word after having given hostages, does an injury, not only to the other contracting power, but also to the hostages themselves. For, though subjects are indeed bound to obey their sovereign who gives them in hostage, that sovereign has not a right wantonly to sacrifice their liberty, and expose their lives to danger without just reasons. Delivered up as a security for their sovereign’s promise, not for the purpose of suffering any harm, — if he entails misfortune on them by violating his faith, he covers himself with double infamy. Pawns and mortgages serve as securities for what is due; and their acquisition indemnifies the part to whom the other fails in his engagements. Hostages are rather pledges of the faith of him who gives them; and it is supposed that he would abhor the idea of sacrificing innocent persons. But, if particular conjunctures oblige a sovereign to abandon the hostages, — if, for example, the party who has received them violates his engagements in the first instance, and, in consequence of his violation, the treaty can no longer be accomplished without exposing the state to danger, — no measure should be left untried for the delivery of those unfortunate hostages; and the state cannot refuse to compensate them for their sufferings, and to make them amends, either in their own persons, or in those of their relatives.

§ 260. The fate of the hostage when he who has given him fails in his engagements.
At the moment when the sovereign who has given the hostage has violated his faith, the latter ceases to retain the character of a hostage, and becomes a prisoner to the party who had received him, and who has now a right to detain him in perpetual captivity. But it becomes a generous prince to refrain from an exertion of his rights at the expense of an innocent individual. And as the hostage is no longer bound by any tie to his own sovereign who has perfidiously abandoned him, — if he chooses to transfer his allegiance to the prince who is now the arbiter of his fate, the latter may acquire a useful subject, instead of a wretched prisoner, the troublesome object of his commiseration. Or he may liberate and dismiss him, on settling with him the conditions.

§ 261. Of the right founded on custom.
We have already observed that the life of a hostage cannot be lawfully taken away on account of the perfidy of the party who has delivered him. The custom of nations, the most constant practice, cannot justify such an instance of barbarous cruelty, repugnant to the law of nature. Even at a time when that dreadful custom was but too much authorized, the great Scipio publicly declared that he would not suffer his vengeance to fall on innocent hostages, but on the persons themselves who had incurred the guilt of perfidy, and that he was incapable of punishing any but armed enemies.7 The emperor Julian made the same declaration.8 All that such a custom can produce, is impunity among the nations who practice it. Whoever is guilty of it cannot complain that another is so too: but every nation may and ought to declare that she considers the action as a barbarity injurious to human nature.


     1.    This principle of the law of nations in this respect precisely applies to guaranties given by private individuals. 5 Barn. & Cres. 269; 2 Dowl 5 Bing. 485. — C.
     2.    Jura negat sibi nata, nihil non arrogat armis. — Horat
     3.    History of the Revolutions of Sweden.
     4.    Grotius. lib. iii. cap. xx. § 55. — Wolfius, Jus Gent. § 503.
     5.    Tschudi. vol. i. p 421.
     6.    Et Romani pignus pacis ex fœdere resituerunt. Tit. Liv. lib. ii. cap. xiii.
     7.    Tit. Liv. lib. xxviii. cap. xxxiv.
     8.    See Grotius, lib. iii. cap. xi. § 18, not. 2.