INTERNATIONAL TREATIES. — In a broad sense, a treaty (t.) is any legal act stipulated between two or more States or other subjects of international law. Treaties constitute the principal source (the only one in positive law) of international law. They perform, mutatis mutandis, in the international sphere the same function that positive legislation fulfills in the sphere of private and public law in relation to natural law.
They originate from the concordant will of two States, since there is as yet no authority in the international community capable of legislating effectively for all nations.
**I. DOCTRINE OF INTERNATIONAL TREATIES. I. Form.** — Although historically there have been purely oral conventions concluded by heads of State and rigorously observed, agreements between States almost always take a written form, and even when concluded orally they are sooner or later reduced to written documents (e.g., the Laval-Mussolini agreements for Ethiopia in 1935). The solemn bilateral or collective documents recording agreements between States are precisely international treaties, which assume various names (agreements, conventions, pacts, protocols, etc.) and are drafted according to a technical process that will be discussed later.
**2. Distinctions.** — According to a doctrine once widely debated (and still upheld by some, e.g., Ottolenghi), a distinction is drawn between treaty-agreements (Vereinbarung) and treaty-contracts (Vertrag). The former would present a certain parallelism with internal laws, leading to the fusion of multiple wills of identical content; such would be all treaties, for example, of international codification of law, or those that create unions or administrative institutions. The latter, on the other hand, would parallel contracts, as they result from the convergence of two or more wills of differing content (e.g., sale or cession of territory, commitment to supply goods under specific conditions, etc.). This distinction may now be considered almost entirely abandoned, with the prevailing view that all treaties form a single category based on the convergence of the wills of the contracting States to achieve a specific purpose.
**3. Parallelism between international treaties and private conventions.** — The parallelism between international conventions and those between private individuals has led some to advocate regulating the former on the model of the latter, and from this parallelism even the generally accepted definition of international treaties as agreements between two or more States to establish, modify, or dissolve a legal relationship among themselves has been derived. While not denying the parallelism of situations and thus of the norms governing them, the analogy should not be pushed to extremes. Having made this premise, it is necessary to determine: a) the requirements for the existence of international conventions; b) those for their validity; and then to ascertain c) the legal effects that ensue, provided such requirements are met.
**4. Existence of international treaties.** — For the existence of an international convention, two or more contracting parties are required (bilateral, plurilateral, or collective conventions), and these parties must possess international legal capacity, qualifying them to conclude agreements and assume international obligations. Thus, included among them are not only States with full international legal capacity (such as protected or vassal States or those subject to legal administration, whose treaty-making capacity is determined by the agreement governing their relations with the protecting or administering State) but also entities to which international legal personality is granted or recognized.
**5. Validity of international treaties.** — Not every manifestation of will by a capable subject is legally sufficient to produce a binding obligation (quite apart from considerations of morality or propriety); the will must be precise and determined and free from error, coercion, or fraud, as in contracts. That an error may occur sufficient to vitiate the manifestation of will is not without characteristic examples, such as that in which the USA and the United Kingdom fell when they accepted the content of letter h of Article 23 of the V Hague Convention of 18 October 1907, believing it to have a meaning entirely different from that attributed to it by the other contracting parties. Cases of fraud are no more frequent, but not impossible. Special consideration must be given to the requirement of coercion, of which there are classic historical examples. If the concept of coercion in international conventions were to be interpreted strictly, nearly all peace treaties would have to be invalidated, since it is rare that a defeated party has willingly accepted the terms of a peace treaty, entered into under the threat of a resumption of hostilities under unequal conditions or of military occupation. Hence, even if the fear is unjustly instilled, many hold that the treaty is valid for the defeated signatory not by virtue of the internal force of the pact but propter necessitatem boni communis.
**6. Object of international treaties.** — Setting aside the real motives that induce States to enter into or accept agreements—motives that are already difficult to scrutinize in private conventions and are in any case irrelevant—any purpose can be the object of an agreement. These purposes must be considered in interpreting the clauses, and in relation to them attempts have been made to group or classify them empirically and approximately, though these classifications have little or no practical or doctrinal significance (territorial, political, economic, financial, labor, emigration agreements, etc.). Reference has been made to the invalidity, even in relations between States, of agreements contra bonos mores, in the name of moral justice, which is superior to the unlimited power of States to assume any obligation. This principle cannot be disregarded, however rare the cases may be, even by States, and it is grounds for invalidating the agreement even by third parties.
**7. Formalities.** — The will of the contracting parties is manifested through qualified organs empowered to bind the State, either directly or, more frequently, through a person vested with authority. It is not sufficient for a delegate or qualified expert to participate in discussing or negotiating the agreement during the negotiations; the binding act must be signed by someone with the power to do so (a plenipotentiary). Thus, the solemn and formal instrument granting such powers (known as full powers) must be examined to ensure that it emanates from the national authority qualified to delegate these powers; that the powers are regular (free from formal defects) and sufficient to validly assume specific obligations (verification of powers, exchange or deposit of full powers, etc.). With the signing of the solemn act, the convention does not enter into force unless it is expressly agreed that it shall do so immediately, pending further ratification. For this to occur, the treaty must be ratified, the ratifications verified or deposited, and, if the agreement is collective, the number of deposited ratifications must reach the threshold determined by the convention. Once this has occurred, unless immediate entry into force is expressly agreed, the term for the convention’s entry into force begins to run.
8. Agreement by way of accession or adhesion
Apart from being a signatory, a State may become party to an agreement by way of accession or adhesion, that is, by manifesting its will to be bound by the agreement. If the agreement is open to all States (e.g., a postal convention), any State may freely adhere to it at any time by depositing its accession in the form prescribed by the convention. If it is open for a specified period, the faculty of adhering expires with the lapse of that period. If accession is admitted only conditionally, the conditions must be observed. At times accession is altogether excluded, since the agreements were concluded with a view to the States that could adhere to them, that is, the consideration of *intuitus personae* applies.9. Registration
With the establishment of the League of Nations, the principle was adopted that international agreements should be registered (Art. 18) as an obligation for member States, and the principle was reaffirmed by the UN Charter (Arts. 102–103). Both the League of Nations and now the UN proceed to publish the registers.Registration: a) aims to ensure that the agreement conforms to the principles of the Charter, which prevails over the agreement (Art. 103); b) aims to give the greatest publicity, also for the aforementioned purpose, to the treaties, so that the collection of treaties of the League of Nations, and now of the UN, constitutes one of the most significant collections of modern treaties, though not exhaustive, since the obligation binds only member States (as for the legal value of registration, it must be noted that it was much debated in relation to Art. 18 of the Covenant; Art. 102 of the Charter entails a sanction, namely, that an unregistered agreement may not be invoked before an organ of the UN).
10. Legal effects
Once a treaty enters into force, those who have accepted it (signatories or adherents) are bound to observe and apply it in good faith. It binds only those who have accepted it, so it cannot impose obligations upon or diminish the rights of third parties. Even if it were to confer benefits upon third parties, it would not bind them without their acceptance. A treaty that imposes upon a State the obligation to cede part of its territory to a neighboring State, held to be neutral, would bind only the defeated State to cede the territory if the neighbor, having accepted the clause, were to demand its observance of its own accord. It must nonetheless be borne in mind that treaties which create legal situations (such as territorial transfers of sovereignty) assume an objective aspect and are valid in relation to the international community, unless a State contests, perhaps by coercive means, the situation thus created.11. Interpretation
Treaties must be interpreted in good faith, taking into account the purposes that inspired them and that they intend to achieve, but within the limits of the commitments actually assumed (here too the analogy with the interpretation of contracts applies).12. Extinction and suspension
Treaties are extinguished by the expiration of the term established by them (provided there are no cases of tacit renewal), by the fulfillment of the object of the treaty, by the occurrence of clauses of termination or forfeiture, by the extinction of one or more of the contracting parties, by the concordant will of the contracting parties, etc. Moreover, a treaty is extinguished when one party violates it and the other denounces it and declares itself released from the commitments assumed, or when unilateral withdrawal is expressly provided for and regulated by the treaty. Finally, it is admitted that a treaty may be extinguished upon denunciation by one of the parties when the factual circumstances on which it was based and which were its premise have substantially ceased to exist (applications of the *rebus sic stantibus* clause). At the very least, such circumstances are sufficient to invoke the revision of treaties.War, in general, entails the suspension of treaties (unless they were expressly concluded for the duration of war and thus become operative in wartime), since it is impossible to apply them, and they regain force upon the cessation of the state of war, unless the war has brought about such changes in the factual circumstances as to render the *rebus sic stantibus* clause applicable. In such a case, it is not war *per se* that brings about the extinction of the treaty, but only indirectly and mediately.
II. GREAT TREATIES
By a term that is merely conventional and approximate, “great treaties” are understood to be those international agreements that mark either a major political or juridical event or historical milestones in the relations among peoples.The first category includes agreements of various kinds. Two years after the discovery of America, for instance, the Treaty of Tordesillas (17 June 1494) was concluded, by which Spain and Portugal agreed on the division of the newly discovered territories. It had enormous importance, though today it is less appreciated. The same may be said of the first Franco-Turkish Capitulation of 1535, inasmuch as it inaugurated the practice of capitulations, which disappeared only a few years ago and had immense significance in relations with the Ottoman Empire and other States to which they were later extended. Yet in relations with Turkey they also marked the definitive collapse of the “impious agreements,” as the first understandings that Christian States had concluded with Islamic ones had been defined and condemned (e.g., the maritime republics with the Barbary States), and which the Holy See had formally condemned. Some agreements of a juridical character may also be termed “great” because they established certain fundamental principles of law, such as the Declaration of Paris of 16 April 1856; the Hague Conventions of 1899 and 1907; and the London Declaration of 1909, etc. These treaties have become increasingly numerous, and as their number grows, the historical value of the earliest ones fades.
Among those that mark true historical milestones, we limit ourselves to indicating the principal ones, which are treated under their respective entries and in relation to the States concerned: the Concordat of Worms (1122), the Peace Treaty of Cateau-Cambrésis (1559), of Westphalia (1648), of Vienna (1815), of Berlin (1878), of Versailles (1919–20), of Paris (1947), and of San Francisco (1951).
III. COLLECTIONS OF TREATIES
In 1693 the first major collections of international treaties appeared, compiled by the French royal printer Léonard (6 vols.), with a preface by Amelot de la Hussaye, and by Leibniz, preceded by a substantial introduction to his *Codex juris gentium* (Hanover 1693). At the same time, the first national collection was begun in England by Rymer. Seven years later, the French theologian Jacques Bernard completed a *Recueil des*treated, etc. in 4 vols. (Amsterdam 1700), which shortly preceded the famous and monumental collection of Dumont (Corps universel diplomatique du droit des gens, etc., Amsterdam 1731-38, in 8 vols. plus the continuation) which stopped at 1731. The Supplements of Rousset continued it up to 1738. Wenck began in 1781 a Codex juris gentium recentissimi, covering the years 1735 to 1772 (3 vols., Leipzig 1781-1795). Finally, in 1790 G. F. V. Martens began his monumental Recueil des traités (8 vols., Göttingen 1791-1801), which contains treaties from 1761 onwards, to which he added 12 vols. of Supplements (ibid. 1802 ff., 1817 ff.) and a Nouveau recueil (4 vols., ibid. 1843 ff.); the work was later continued by various successive editors in several series. In 1892 the Institut de droit international advocated the creation of an International Bureau for a general publication of treaties, but a conference called for this purpose by the Swiss government in Berne (25 Sept. 1894) did not go beyond an exchange of ideas. The initiative, as mentioned above, was resumed with the Covenant of the League of Nations and then with the Charter of the United Nations, which led to the publication of a voluminous Recueil, though this is not complete, for the reasons mentioned above.
Almost all States now have purely national collections of treaties (including Italy), nor are there lacking private collections of great scope such as that begun by Bruns, or of more limited scope (Strupp), or anthologies for mainly academic use (Albin, Anchieri, etc.) and collections by subject (Giannini), etc.
IV. HISTORY OF TREATIES
Under this heading has been designated that special history which is not intended to illustrate the internal and external history of particular treaties, but to reconstruct the history of relations between peoples through diplomatic treaties, considered as the most solemn expression of those relations (archives of peoples according to De Mably; history of civilization according to Albicini; history of the legal society of States according to Schiattarella), and those which mark their fundamental stages. This conception, linked to the tendency to make the history of treaties an auxiliary discipline for the teaching of international law (for the same reason teaching was combined with that of diplomacy, understood as diplomatic style or technique of international relations), may be considered outdated, but the old denomination continues to be used, by force of tradition, alongside others such as history of international relations, history of foreign policy, history of international politics, diplomatic history, etc., which all ultimately return to history considered particularly from the diplomatic standpoint, and therefore, as mentioned above, a special history in relation to general history.It may finally be noted that similar criteria have been applied in relation to the Holy See in speaking of the history of concordats, and the history of treaties and concordats has not failed to be combined; while others have preferred to speak of the history of papal diplomacy, which is in the end more correct and of broader scope, since with some States the Holy See has neither concluded treaties nor concordats and yet diplomatic relations exist, of which a history can be written.
V. TECHNIQUE OF TREATIES
Treaties, whatever their designation (solemn conventions, conventions, pacts, agreements, protocols, declarations, exchanges of notes, in the oldest terminology, capitulations), are, from a technical standpoint, the diplomatic documents which most reflect the traditionalism of diplomatic style, also because they usually retain the solemn form, even when drawn up by new international bodies such as the League of Nations and the United Nations. Only exchanges of notes are not solemn and have become a frequent and flexible means of concluding agreements, even of considerable importance. Oral agreements are not solemn and have almost fallen into disuse; for these no technique or formalities are required.Technically, a treaty, like all solemn diplomatic documents, is divided into three parts.
In the first (protocol, introductory part) are indicated, first (now fallen into disuse, as was done in old treaties, the invocation to the Most Holy Trinity) the contracting parties, then the aims which induce the parties to conclude the agreement, which may also be accompanied by a summary narrative of the events which led to the agreement (especially in peace treaties), a narrative which is often inaccurate or falsified and which in any case does not constitute history. This is followed by the list of plenipotentiaries, mention of the verification or deposit of full powers, and the declaration of intent to conclude the agreement.
The second part (mesocolo) comprises the norms intended specifically to achieve the aims indicated in the introductory part, or such as are presumed to be (especially in peace treaties), and which represent the central and substantive part of the agreement. To these norms follow the so-called style clauses (sometimes more numerous than the former), which determine who is entitled to sign the document, who may adhere to or accede to it, whether signature, adhesion or ratification may be accompanied by reservations, the period within which signature (treaties open for a fixed or indefinite period) or adhesion may take place and by what procedure, how and when ratifications are to be effected, the period and conditions under which the treaty enters into force, the procedure for revision, denunciation and the period within which they become operative, the duration of the treaty (if for a fixed period), the means of settling disputes arising from the interpretation or application of the treaty (arbitration clause, competence of the Court of Justice or of a special jurisdiction), the language or languages used and that which is authoritative.
This last clause is sometimes inserted in the third part of the document (eschatocol), which in any case indicates the date and place at which the document is signed, the archive of the government or body with which the original text is deposited (and which usually mentions the collection of ratifications, adhesions, denunciations, giving notice thereof to the signatories, and draws up the minutes of the fulfilment of the conditions which bring the treaty into force and which must therefore be notified to the signatories or adherents), and finally the signatures of the plenipotentiaries, with their possible declarations, reservations, etc. The plenipotentiaries may sign simply or ad referendum. Reservations must be permitted and provided for by the treaty, or at least not contrary to II.
Some of these style clauses are new, while others have fallen into disuse, such as that of the solemn sworn confirmation of the pact, the intervention of the Supreme Pontiff in the confirmation and execution of the agreement (which survived for some time even after the fall of the Respublica christiana).