The Principles of Natural and Politic Law (1748)

Jean Jacques Burlamaqui

Of public treaties in general.

I. THE subject of public treaties constitutes a considerable part of the law of nations, and deserves to have its principles and rules explained with some exactness. By public treaties, we mean such agreements as can be made only by public authority, or those, which sovereigns, considered as such, make with each other, concerning things, which directly concern the welfare of the state This is what distinguishes these agreements, not only from those, which individuals make with each other, but also from the contracts of kings in regard to their private affairs.

II. What we have before observed, concerning the necessity of introducing conventions betwixt private men, and the advantages arising from them, may be applied to nations and different states. Nations may, by means of treaties, unite themselves more particularly into a society, which shall reciprocally assure them of seasonable assistance, either for the necessaries and conveniences of life, or to provide for their greater security upon the breaking out of a war.

III. As this is the case, sovereigns are no less obliged, than individuals, inviolably to keep their word, and be faithful to their engagements. The law of nations renders this an indispensable duty; for it is evident, that, were it otherwise, not only public treaties would be useless to states, but moreover, that the violation of these would throw them into a state of diffidence and continual war; that is to say, into the most terrible situation. The obligation therefore of sovereigns, in this respect, is so much the stronger, as the violation of this duty has more dangerous consequences, which interest the public felicity. The sanctity of an oath, which generally accompanies solemn treaties, is an additional motive to engage princes to observe them with the utmost fidelity; and certainly nothing is more shameful for sovereigns, who so rigorously punish such of their subjects, as fail in their engagements, than to sport with treaties and public faith, and to look upon these only, as the means of deceiving each other.

The royal word ought therefore to be inviolable and sacred. But there is reason to apprehend, that if princes are not more attentive to this point, this expression will soon degenerate into an opposite sense, in the same manner as formerly Carthaginian faith1 was taken for perfidy.

IV. We must likewise observe, that the several principles, already established concerning the validity of conventions in general, agree to public treaties, as well as the contracts of individuals. In both, therefore, there must be a serious consent, properly declared, and exempt from error, fraud, and violence.

V. If treaties, made in those circumstances, be obligatory between the respective states or sovereigns, they are also binding with regard to the subjects of each prince in particular. They oblige as compacts between the contracting powers; but they have no force of laws with respect to the subjects considered as such; for it is evident, that two sovereigns, who conclude a treaty, lay their subjects thereby under an obligation of doing nothing contrary to it.

VI. There are several distinctions of public treaties; and 1. some turn simply on things, to which we were before obliged by the law of nature; and others superadd some particulars to the duties of natural law.

VII. Under the former head we may rank all those treaties, by which we are purely and simply engaged to do no injury to others, but, on the contrary, to perform all the duties of humanity towards them. Among civilized nations, who profess to follow the laws of nature, such treaties are not necessary. Duty alone is sufficient, without a formal engagement. But among the ancients, these treaties were thought expedient, the common opinion being, that they were obliged to observe the laws of humanity only to fellow subjects, and that they might consider all strangers as foes, and treat them as such, unless they had entered into some engagement to the contrary; and of this we have many instances in history. The profession of freebooter, or private, was no way shameful among several nations; and the word hostis, which the Romans used to express an enemy, originally signified no more than a stranger.

VIII. Under the second kind I comprehend all those compacts by which two nations enter into some new, or more particular obligation; as when they formally engage to things, to which they were not bound, but in virtue of an imperfect obligation, or even to which they were no ways before obliged.

IX. 2. Treaties, by which we engage to something more than what we are obliged to, in virtue of the law of nature, are also of two kinds; some equal, others unequal.

3. Both are made either in time of war, or in full peace.

X. Equal treaties are those, contracted with an entire equality on both sides; that is to say, when not only the engagements and promises are equal on both sides, either purely and simply, or in proportion to the strength of each contracting party; but also, when they engage on the same footing; so that neither of the parties is in any respect inferior to the other.

XI. These treaties are made either with a view to commerce, or to confederacy in war, or in short to any other matters. With respect to commerce, for example, by stipulating, that the subjects, on either side, shall be free from all custom or toll, or that no more shall be demanded of them, than of the natives of the country, etc. Equal treaties, or leagues relating to war, are, when we stipulate for example, that each shall furnish the other an equal number of troops, ships, and other things; and this in all kinds of war, defensive as well as offensive, or in defensive only, etc. Lastly, treaties of equality may also turn upon any other matter; as when it is agreed, that one shall have no forts on the other’s frontiers; that one shall not grant protection to the other’s subjects, in some criminal cases, but order them to be seized and sent back; that one shall not give the other’s enemies passage through his country, and the like.

XII. What we have been saying sufficiently shows the meaning of unequal treaties. And these are, when the promises are either unequal, or such as lay harder conditions on one of the parties, than on the other. The inequality of the things stipulated is sometimes on the side of the most powerful confederate, as when he promises his assistance to the other, without requiring the like; and sometimes on the side of the inferior confederate, as when he engages to do more for the stronger, than the latter promises in return.

XIII. All the conditions of unequal treaties are not of the same nature; some there are, which, though burdensome to the inferior ally, yet leave the sovereignty intire; others on the contrary, include a diminution of the independence, and sovereignty of the inferior ally.

Thus, In the treaties between the Romans, and the Carthaginians, at the end of the second Punic war, it was stipulated, that the Carthaginians should not begin any war, without the consent of the Roman people; an article, which evidently diminished the sovereignty of Carthage, and made her dependent on Rome.

But the sovereignty of the inferior ally continues intire; though he engages, for example, to pay the other’s army, to defray the expences of the war, to dismantle some towns, to give hostages, to look upon all those as friends or enemies, who are friends or enemies to the other, to have no forts, or strong holds in certain parts, to avoid sailing in particular seas, to acknowledge the preeminence of the other, and, upon occasion, to shew reverence and honor to his power and majesty, etc.

XIV. However, though these, and other similar conditions, do not diminish the sovereignty, it is certain that such treaties of inequality are often of so delicate a nature, as to require the greatest circumspection, and that if the prince, who is superior to the other in dignity, surpasses him also considerably in strength and power, it is to be feared, that the former will gradually acquire an absolute sovereignty over him, especially if the confederacy be perpetual.

XV. 4. Public treaties are also divided into real and personal. The latter are those, made with a prince purely in regard to his person, and expire with him. The former are such, as are made rather with the whole body of the state, than with the king or government, and which consequently outlive those, who made them and oblige their successors.

XVI. To know which of these two classes every treaty belongs to, the following rules may be laid down.

1. We must first attend to the form and phrase of the treaty, to its clauses, and the views proposed by the contracting parties. Utrum autem in rem, an in personam factum est, non minus ex verbis, quam ex mente convenientium æstimandum est.2 Thus, if there be an express clause, mentioning, that the treaty is perpetual, or for a certain number of years, or for the good of the state, or with the king for him and his successors, we may conclude, that the treaty is real.

2. Every treaty, made with a republic, is in its own nature real, because the subject, with whom we contract it, is a thing permanent.

3. Though the government should happen to be changed from a republic into a monarchy, the treaty is still in force, because the body is still the same, and has only another chief.

4. We must however make an exception here, which is, when it appears that the preservation of the republican government was the true cause of the treaty; as when two republics enter into an alliance, by which they agree to assist one another, against such, as shall endeavour by force to alter their constitution, and deprive them of their liberties.

5. In case of doubt every public treaty, made with a king, ought to be deemed real, because in dubious cases, the king is supposed to act as chief, and for the good of the state.

6. Hence it follows, that as, after the change of a democracy into a monarchy, the treaty is still in force, in regard to the new sovereign; so if the government, from a monarchy, becomes a republic, the treaty made with the king does not expire, unless it was manifestly personal.

7. Every treaty of peace is real in its own nature, and ought to be kept by the successor; for so soon as the conditions of the treaty have been punctually fulfilled, the peace effectually effaces the injuries, which excited the war, and restores the nations to their natural situation.

8. If one of the confederates has fulfilled what the treaty obliged him to, and the other should die before he performs the engagements on his part, the successor of the deceased king is obliged either intirely to indemnify the other party for what he has performed, or to fulfil his predecessor’s engagement.

9. But if nothing is executed on either part, or the performances on both sides are equal, then if the treaty tends directly to the personal advantage of the king, or his family, it is evident, that so soon as he dies, or his family is extinct, the treaty must also expire.

10. Lastly we must observe, that it is grown into a custom for successors to renew, at least in general terms, even the treaties manifestly acknowledged for real, that they may be the more strongly bound to observe them, and may not think themselves dispensed from that obligation, under a pretext that they have different ideas concerning the interests of the state, from those of their predecessors.

XVII. Concerning treaties, or alliances, it is often disputed, whether they may be lawfully made with those, who do not profess the true religion? I answer, that by the law of nature there is no difficulty in this point. The right of making alliances is common to all men, and has nothing opposite to the principles of true religion; which is so far from condemning prudence and humanity, that it strongly recommends both.3

XVIII. To judge rightly of the causes, which put an end to public treaties, we must carefully attend to the rule of conventions in general.

1. A treaty concluded for a certain time, expires at the end of the term agreed on.

2. When a treaty is once expired, it must not be supposed to be tacitly renewed; for a new obligation is not easily presumed.

3. And therefore, if, after the treaty expires, some acts are continued, which seem conformable to the terms of the preceding alliance, they ought rather to be looked upon, as simple marks of friendship and benevolence, than as a tacit renovation of the treaty.

4. We must however make this exception, unless such acts intervene, as can bear no other construction, than that of a tacit renovation of the preceding compact. Thus, for example, if one ally has engaged to pay another a certain sum annually, and after the expiration of the term of the alliance, the same sum be paid the following year, the alliance is tacitly renewed for that year.

5. It is in the nature of all compacts in general, that when one of the parties violates the engagements, into which he had entered by treaty, the other is freed, and may refuse to stand to the agreement; for generally each article of the treaty has the force of a condition, the want of which renders it void.

6. This is generally the case, that is to say, when there is no agreement otherwise; for sometimes this clause is inserted, that the violation of any single article of the treaty shall not break it intirely; to the end, that neither party should fly from their engagements for every slight offence. But he who, by the action of another, suffers any damage, ought to be indemnified in some shape or another.

XIX. None but the sovereign can make alliances and treaties, either by himself, or by his ministers. Treaties concluded by ministers oblige the sovereign and the state, only when the ministers have been duly authorized to make them, and have done nothing contrary to their orders and instructions. And here it may be observed, that among the Romans the word foedus, a public compact, or solemn agreement, signified a treaty made by order of the sovereign power, or that had been afterwards ratified; but when public persons, or ministers of state, had promised something relating to the sovereign power, without advice and command from it, this was called sponsio, or a simple promise and engagement.

XX. In general it is certain, that when ministers, without the order of their sovereign, conclude a treaty concerning public affairs, the latter is not obliged to stand to it; and the minister, who has entered into the negotiation without instructions, may be punished according to the exigency of the case. However there may be circumstances, in which a prince is obliged, either by the rules of prudence, or even those of justice and equity, to ratify a treaty, though concluded without his orders.

XXI. When a sovereign is informed of a treaty, made by one of his ministers without his orders, his silence alone does not imply a ratification, unless it be accompanied with some act, or other circumstance, which cannot well bear another explication. And much more, if the agreement was made upon condition of its being ratified by the sovereign, it is of no force till he has ratified it in a formal manner.


   1.     Punica fides.
   2.    Leg. vii. sect. viii ff. de Pactis.
   3.    See Grotius on war and peace, book ii. chap. xv. sect. 8, 9, 10, 11, 12.