The first step in such a study is to define precisely the scope of the analysis, both by outlining the main features of the concept of peace treaty (§ 1) and by defining the geographical and historical limits of the practice under consideration (§ 2). It will then be possible to highlight the difficulties presented by the subject and identify ways of overcoming them (§ 3). 

§ 1. Identification of the concept

10. The concept of a peace treaty overlaps with different categories of instruments, which need to be distinguished. In truth, this operation does not present insurmountable difficulties, at least on the theoretical level. Indeed, there is fairly broad agreement among authors as to what constitutes « a peace treaty in the true sense of the word »¹. As early as the fourteenth century, Bartole wrote that « peace is nothing else than an agreement by the terms of which war already begun is brought to an end »². Later, Vattel similarly considered that 

« When Powers at war agree to lay down their arms, the Agreement or Contract in which they stipulate the conditions of peace and regulate the manner in which it is to be re-established and maintained is called a Peace Treaty« ³.

These converging definitions suggest three necessary and sufficient criteria for qualifying a treaty as a peace treaty and for excluding instruments that are merely neighbouring. A peace treaty thus presupposes cumulatively the existence of a war between the parties (A.), the termination of that war (B.) and recourse to a treaty form (C.).

A. The peace treaty presupposes the existence of a war

11. The first element of identification that emerges from Vattel’s definition is the existence of a war between the parties. This condition is shared by all authors throughout the ages. Pufendorf refers to the peace treaty as one of those « public agreements which presuppose a state of war« ⁴. In the twentieth century, Kelsen wrote along the same lines: « [t]he state of war […] can only be terminated by a peace treaty »⁵. On the face of it, this requirement is a truism. In reality, it is essential in order to distinguish peace treaties from certain related categories of instruments. The distinction is made tricky by the hesitations of doctrine as to the very notion of war⁶. It is not necessary, at this stage, to dwell on the various conceptions held in this respect⁷. It suffices to note that authors agree, in principle, on the first words of the definition: « war is armed struggle between States »⁸. This summary definition makes it possible to distinguish the concept of a peace treaty from two related categories of instruments: those concluded between States that have not resorted to the use of force, on the one hand (1.); and those concluded during an armed conflict not of an international character, on the other (2.).

1. The exclusion of international agreements concluded in the absence of armed conflict

12. The peace treaties that are the subject of this study are not the only international instruments designed to ensure and organise peace between nations. International history is rich in so-called « peace and friendship » treaties, under which the parties organise various aspects of their relations, both politically and economically⁹. These treaties, concluded without the prior use of force, are often very similar in appearance to treaties concluded to end a war. Treaties in each of these categories cannot be distinguished on the basis of their title alone. They are all peacetreaties, a term that may be accompanied by a number of epithets – friendship, trade, navigation, etc. – in either case. For example, the Treaty of Peace, Friendship, Boundaries and Final Arrangement concluded in Guadalupe Hidalgo between the United States and Mexico to end the war between them¹⁰ does not really differ in its title from the Treaty of Peace, Friendship, Commerce and Navigation concluded in Santiago between Chile and the United States in the absence of any prior recourse to armed force¹¹. The provisions of each of these instruments are equally confusing. The first article of the Treaty of Guadalupe Hidalgo states that « [t]here shall be firm and universal peace between the United States of America and the Mexican republic ». The Treaty of Santiago states very similarly that « [t]here shall be a perfect, firm, and inviolable peace and sincere friendship between the United States of America and the republic of Chile ». In each case, the treaty states that there will be peace between the parties in the future. The instruments thus share a provision that is one of the most constant and fundamental in the practice of restoring peace¹². The difference between the two instruments is no less significant. It stems both from the circumstances in which the treaties were concluded and from the status of the States at the time of their conclusion. The preambles to the treaties under consideration highlight the nature of this difference. The preamble to the Treaty of Santiago presents the parties as « desiring to make firm and lasting the friendship and good understanding which happily prevails between both nations »¹³. The preamble to the Treaty of Guadalupe Hidalgo states that the two States are « animated by a sincere desire to put an end to the calamities of the war which unhappily exists between the two republics, and to establish upon a solid basis relations of peace and friendship »¹⁴.

In the first treaty, peace already existed when the treaty was signed, as evidenced by the use of the verb « to prevail » in the present tense. It is simply a question of making it « firm and lasting ». In contrast, it is the existence of war that is expressed in the present tense by the second treaty. Peace is merely the object of the parties’ desire and needs to be « established ». The two instruments therefore do not have the same relationship to peace: the Treaty of Santiago consolidates it; the Treaty of Guadalupe Hidalgo establishes it. This merely confirmatory nature of an already existing state of peace is a constant feature of so-called « peace and friendship » treaties. The absence of a prior war between the parties makes it possible to distinguish these treaties from those that doctrine has constantly taken as its object when referring to the notion of peace treaty.

13. However, the hesitations of practice and doctrine sometimes make it difficult to characterise the respective situations of the parties to the treaty, and therefore to qualify the treaty itself. Assessing whether there was a war between the States concerned at the time the peace treaty was concluded raises two difficulties. 

The first relates to the qualification of armed confrontations between States as war. It does not seem necessary, in this respect, to adhere to a formalist conception of the concept. As international law stands, there is no longer any difference in regime between a « declared war » and « any other armed conflict arising between two or more [States], even if the state of war is not recognised by one of them »¹⁵. Distinguishing between the concepts is therefore no longer of much use, either in terms of the law applicable or the methods of restoring peace. The existence of « recourse to armed force between States », to use the wording adopted by the Criminal Tribunal for the former Yugoslavia, will in principle suffice to allow the classification of a genuine peace treaty¹⁶. The absence of a declaration of war is therefore not sufficient to disqualify the treaty concluded in 1980 between Honduras and El Salvador or the agreement concluded in 2000 between Eritrea and Ethiopia¹⁷. The low intensity of the confrontations should not be an obstacle either, as long as the belligerents behaved as if they were in a state of war. The Treaty of Fontainebleau, concluded in 1785 between the United Provinces of the Netherlands and the Holy Roman Empire, was preceded only by a few bursts of machine-gun fire, the only casualty of which was said to have been a cooking pot¹⁸. Nevertheless, war was formally declared and the Treaty of Fontainebleau was conceived by the parties as a true peace treaty. It is only necessary to exclude agreements concluded following specific military incidents or before the actual outbreak of hostilities¹⁹. We will therefore exclude from the study the treaty concluded in 1984 between Argentina and Chile, putting an end to the episode known as the « Beagle Conflict »²⁰. Although the dispute gave rise to intense military preparations, it was averted at the last minute by Vatican intervention: neither declared nor begun, the Beagle War did not take place²¹.

A second difficulty arises when the state of war dividing the parties has already ended by the time the treaty is concluded. In 1978, the Treaty of Peace and Friendship concluded between China and Japan²² followed on from a joint declaration of 1972, in which the two parties had stated that « [t]he abnormal state of affairs that has hitherto existed between Japan and the People’s Republic of China is terminated on the date on which this Joint Communique is issued« ²³. It follows from this declaration that the war between the two States no longer existed when the 1978 Treaty was concluded. The latter cannot therefore be regarded as a peace treaty within the meaning of this study. However, the classification of treaties is by no means self-evident. On the contrary, it is based on a process of interpretation which may lead to apparently similar situations being treated in different ways. For example, the treaty concluded in 1994 between Israel and Jordan is considered to be a genuine peace treaty, despite the joint declaration of 25 July of the same year in which the parties announced that « the state of belligerence between Jordan and Israel has ended »²⁴. This apparent contradiction is based on three observations. Firstly, legal scholars have questioned the legal value of the parties’ prior declaration²⁵. Secondly, the scope of this declaration is rendered uncertain by the parties’ acknowledgement of the need to « vigorously pursue their negotiations with a view to achieving a state of peace« ²⁶. Finally, it is only from the entry into force of the treaty that peace will be considered to have been established²⁷ and that the parties will be subject to the « principles of international law governing relations between States in time of peace »²⁸. The theoretical clarity of the concept of a peace treaty is blurred here by the complexities of practice. The difficulty is the same when it comes to distinguishing peace treaties from agreements ending non-international armed conflicts. 

2. Exclusion of agreements concluded during non-international armed conflicts

14. The relative constancy of both practice and doctrine in using the expression ‘peace treaty’ is an exception to the classic indifference of the law of treaties to the naming of treaty instruments²⁹. At the end of the nineteenth century, after taking note of the varied lexicon in use among diplomats, one author was careful to point out that « [o]n dit Traités de paix et non convention de paix »³⁰. This prescription was not only the result of a well-established habit: it was also the sign of a concept that had been perfectly identified by the international lawyers of the time³¹. The term peace agreement, promoted by contemporary practice, cannot claim the same degree of doctrinal definition. The fact is that,

« [t]here is no legal definition of the term « peace agreement » or « peace accord »; it is a lay term used to cover treaties between two or more states, agreements between states and nonstate groups, and even agreement between domestic parties »³².

On the one hand, doctrine has long accepted that « [p]eace treaties are transactions […] that States have with one another« ³³; on the other hand, « the contemporary label ‘peace agreement’ is most often attached to […] agreements between parties to a violent ‘intrastate’ conflict »³⁴. Far from being indifferent, the denomination of treaty instruments is, on the contrary, particularly significant in the field of peacemaking: while the expression peace agreement designates both international treaties and commitments between non-state armed groups, the notion of peace treaty is exclusive of any agreement concluded at a non-international level. The very title of this study therefore excludes internal peace agreements. 

Formally valid, this explanation is nonetheless insufficient if we consider that it depends exclusively on the chosen terms of the subject. A seemingly insignificant change in the title of the study would have been enough to broaden its scope considerably. Certainly, it would have been a very different study than one entitled The peace agreement in public international law. It is therefore not enough to circumscribe the scope covered by the title chosen: the deliberately restrictive wording must also be justified. It is true that the need for such a restriction is not obvious. The similarity of the phenomena in question and the common purpose of the instruments concluded are reasons likely to authorise numerous comparisons between international and domestic practices of conventional return to peace. Indeed, studies conducted in the field of jus post bellum consider the end of intra- and inter-state conflicts in the same way³⁵. However, there are several reasons to doubt the appropriateness of this approach. The similarity of the facts in no way implies that the situations are identical in legal terms. It is true that internal armed groups fight in principle under the control and protection of international law. Similarly, depending on the circumstances of the case, they may be recognised as having the capacity to conclude agreements governed by that law³⁶ , or even genuine « treaties »³⁷. However, the international personality of these groups is limited and they are only eligible to benefit from certain provisions, in particular humanitarian provisions³⁸. Agreements concluded to put an end to internal hostilities are therefore only recognised by contemporary doctrine as having a « hybrid » nature³⁹. As a result, an internal peace agreement is not the expression of international law alone, but of the partial legal order resulting from the conjunction of international law and the domestic law of the State concerned⁴⁰. This order combines, in varying proportions, the requirements of domestic law and those of international law. Christine Bell is therefore justified in considering that the conclusion of such agreements is governed less by international law than by a « lex pacificatoria […] understood as a transnational area of law »⁴¹. On the contrary, international treaties are essentially indifferent to the requirements of domestic law and the States that conclude them are in principle fully subject to the rights and obligations of international law. As a result, despite the existence of a certain area of intersection, the two categories of instruments derive from rules that are different in nature. The Special Court for Sierra Leone can therefore rightly consider that « a peace agreement which settles an internal armed conflict cannot be ascribed the same status as one which settles an international armed conflict »⁴². Considering the different forms of conflict on the same level therefore leads to projecting onto one the characteristics of the other, and vice versa, ultimately erasing the specific features of the instruments intended to put an end to them. This observation does not preclude a comparison between each of the two categories of instruments, nor does it prejudge the extent of their common ground. From a methodological point of view, it merely suggests that the techniques should not be confused by postulating their identity on the basis of a vague similarity of purpose.

15. However, the implementation of the distinction between international and internal conflicts is not a simple matter⁴³. The terms used to designate an instrument do not necessarily presage the nature of the conflict to which it puts an end: the Algiers « Agreement » puts an end to a conflict that has the characteristics of a conventional war between States, and its status as a peace treaty, within the meaning of this study, is therefore beyond doubt⁴⁴. Nor is there any reason to hesitate when the agreement is concluded on both sides by non-state armed groups: as it is impossible to classify the agreement as a war, it is equally impossible to classify it as a peace treaty. In reality, the difficulty arises only in certain borderline cases. This is the case in particular when peace agreements

« have both state and nonstate parties. This pose a fundamental difficulty for categorizing peace agreements as either domestic or international legal documents, placing their legal status under dispute and affecting which bodies of international or domestic law apply »⁴⁵.

A prime example is the 1995 Dayton Agreement⁴⁶. Initially a civil conflict, it quickly became a mixed conflict⁴⁷. In the present case, the complexity of the situation is not such as to prevent it from being classified as a war in the strict sense. Indeed, the Court emphasised in relation to the hostilities in Bosnia-Herzegovina that

« There is […] ample evidence of the participation, direct or indirect, of the official army of the FRY, together with the armed forces of the Bosnian Serbs, in military operations in Bosnia-Herzegovina in the years preceding the events in Srebrenica. This participation was repeatedly denounced by the political bodies of the United Nations, which called on the FRY to put an end to it »⁴⁸.

There was therefore a direct use of armed force between the Federal Republic of Yugoslavia and Bosnia-Herzegovina sufficient to constitute war. It is irrelevant, moreover, that many of the documents annexed to the General Framework Agreement bear the signature only of the Republic of Bosnia and Herzegovina and the internal entities of which it is composed. Signed as parties by three belligerent States, the Dayton Framework Agreement and its annexes indisputably have the character of an « international agreement » « concluded in writing between States », « embodied in… several related instruments » and « governed by international law ». Therefore, despite their « particular name », these agreements constitute an international treaty in the strict sense of Article 2 of the Vienna Convention⁴⁹. The Dayton General Framework Agreement must therefore be regarded as a genuine peace treaty⁵⁰.

However, it is not possible to consider all agreements relating to the accession of a new state to independence following an armed struggle to be peace treaties. A distinction must be made, based on the status of the group claiming independence at the time the agreement is concluded. The independence agreement may be conceived as a peace treaty within the meaning of this study if the group concerned has already acquired its independence at the time the treaty is concluded and already has full powers under international law⁵¹. When the United States concluded the Treaty of Versailles of 1783 with Great Britain, it was acting and was in all respects already considered to be a State⁵². The recognition contained in the treaty was declaratory and consisted above all of Great Britain relinquishing all its claims to the territories it had formerly possessed⁵³. The situation is different when the new state has not yet been constituted when the treaty is concluded. This is the case, for example, with the agreements relating to the independence of Algeria. The text of the Evian agreements of 18 March 1962 attests to the fact that the independence of Algeria was envisaged by both parties as the result of the implementation of the agreements, and not as a prerequisite for their signature⁵⁴. This conclusion is not only due to the asymmetrical designation of the parties⁵⁵. It is due above all to the very content of the agreements. Unlike Great Britain in 1783, France did not acknowledge that independence had already been achieved. The parties agreed the « conditions »⁵⁶ for self-determination subject to prior « consultation »⁵⁷. They set out by common agreement the « consequences » – including recognition by France and the transfer of powers⁵⁸ – that would be achieved « [i]f the solution of independence and cooperation is adopted »⁵⁹. A joint « General Declaration » similarly referred to « the formation, following self-determination, of an independent and sovereign State »⁶⁰. Algeria’s independence was officially proclaimed on 5 July 1962, five days after the consultation provided for in the March agreement. The signatories of the agreements did not therefore consider Algeria to be a State on the day they signed the agreement: they simply felt that it was destined to become one. Since it had not yet acquired an inter-State character, Algeria could not be in a state of war with France in the traditional sense of the term under international law⁶¹. From this point of view, therefore, it was not in a position to conclude a peace treaty within the meaning of this study. 

However, there is no question of being blind to the changes that can occur in the situation of a state during and alongside peace negotiations. The evolution of the status of Palestine illustrates the way in which a community, initially devoid of statehood, gradually acquires the status of a state. These developments are the result both of the stages of the peace process itself and of unilateral initiatives by the parties. The creation, in line with the Oslo Accords, of a Palestinian National Authority vested with certain powers and the organisation of elections have gradually strengthened the links between the political power, the territory and the population of Palestine⁶². By simultaneously strengthening the effectiveness and legitimacy of Palestinian political bodies, these negotiated advances gradually brought Palestine closer to the State model, which some scholars were unable to recognise before the peace process began⁶³. They have enabled the Palestinian authorities, this time without any negotiations, to successfully apply for Palestine to be admitted as a member state of UNESCO⁶⁴ and as an observer state at the United Nations⁶⁵. The point is not to draw excessive conclusions from these developments. Nevertheless, it is important to stress the impact they could have on the legal qualification of a definitive instrument: it is revealing, in this respect, that in 2010 the General Assembly specifically called for the conclusion of a « peace treaty » between Palestine and Israel⁶⁶. The rigidity of legal categories must therefore be reconciled with the fluidity of the situations they designate: whether the parties to an internal armed conflict acquire State status, their struggle will become a war, the outcome of which will call for the conclusion of a peace treaty. 

B. The peace treaty presupposes the end of the war

16. The existence of a war is not sufficient to characterise a peace treaty. In the course of a war, the belligerent states may conclude a number of agreements « concerning the conduct and termination of warlike operations »⁶⁷. Not all of these are peace treaties. Peace treaties are characterised by the fact that they are concluded during a war and bring it to an end. Pufendorf writes of agreements which presuppose a state of war that « there are two kinds: some which allow the state of war to continue […]; others which bring it to an end entirely« ⁶⁸. The Peace Treaty concerns only agreements of the second kind. Wolff also writes that « [t]he conclusion of the peace ends the war »⁶⁹. The definitive nature of the settlement is particularly well established in the doctrine of the late nineteenth century. AlphonseRivier considered that « [b]y peace, the cessation of hostilities is imposed not for a specific time, but indefinitely; the war is over, once and for all »⁷⁰. In the twentieth century, Hans Kelsen similarly wrote that « the specific function of a peace treaty is to put an end to war »⁷¹. This definitive nature of the settlement achieved by the peace treaty leads to the exclusion of two categories of instruments, which do not have the effect of definitively ending the war⁷². These are, on the one hand, instruments relating to the prior suspension of hostilities (1.) and, on the other hand, preparatory or subsequent instruments concluded respectively with a view to the conclusion or application of the peace treaty (2.).

1. Exclusion from agreements on the temporary cessation of hostilities

17. The conclusion of a peace treaty is often preceded by one or more agreements organising the suspension of hostilities between the belligerents⁷³. This suspension may take several forms, sometimes unilateral, more frequently conventional: capitulations, suspensions of arms, truces, armistices, ceasefires⁷⁴. The purpose of these instruments, which vary in form and regime, is in principle to organise a simple suspension of military confrontation, so as to allow the parties to find a definitive political solution. The armistice agreement concluded in 1814 between defeated France and the European powers thus indicates the desire of the parties to « agree on an act which, without prejudging the provisions of peace, contains the stipulations of a suspension of hostilities, and which will be followed, as soon as possible, by a peace treaty »⁷⁵. The distinction is therefore clear: « an armistice is not peace »⁷⁶. The content of these agreements varies, as does their scope. They may be local or general in scope, involve only specific military obligations or prejudge definitive political decisions. Depending on their nature, temporary instruments may be signed by the military authorities themselves or require the intervention of a representative formally authorised to bind the state⁷⁷. In principle, instruments of this nature comprise only limited and temporary concessions. The armistice concluded in 1948 between Israel and its neighbours stipulates that « [t]he provisions of the present Convention are dictated solely by military considerations, and are valid only for the duration of the armistice »⁷⁸. Marcel Sibert, who in 1933 recognised the armistice as the most extensive convention relating to hostilities, was at the same time careful to emphasise that it remained « far from equivalent to the peace treaty »⁷⁹.

18. It is true that the twentieth century saw these instruments evolve substantially. On the one hand, one of the consequences of the prohibition on the use of force was to call into question the only temporary nature of the cessation of hostilities⁸⁰. The armistice of 11 November 1918 was concluded for a period of thirty-six days, and was renewed on several occasions⁸¹. Recent agreements no longer contain such clear indications as to their precariousness. The 1949 armistice between Egypt and Israel was concluded at the invitation of the Security Council for an indefinite period⁸². Nonetheless, its precariousness is reflected in a reference to the objective of « restoring permanent peace »⁸³. On the other hand, the content of armistices has evolved to come ever closer to the classic material content of peace treaties⁸⁴. However, the parties are still careful to emphasise the non-final nature of the settlement reached. The agreement on the disengagement of forces concluded between Egypt and Israel on 18 January 1974 contains a provision in which the parties state that « this Agreement shall not be considered by Egypt and Israel as a final peace agreement »⁸⁵. The need to distinguish between temporary and definitive instruments is not without significance, even in recent practice: the Algiers Agreement of 12 December 2000, in which Eritrea and Ethiopia undertook to put a « permanent » end to hostilities⁸⁶ , was preceded on 18 June of the same year by an agreement on the cessation of hostilities⁸⁷. This agreement was only partial, and did not put an end to the war between the two states: it cannot therefore be described as a peace treaty. 

2. Exclusion of preparatory and subsequent agreements to the peace treaty

19. The same applies to other agreements which, although they go beyond the mere cessation of hostilities, cannot be considered as peace treaties because they are either preparatory or subsequent in nature⁸⁸. The historical form of preparatory agreements is the preliminary peace treaty, which is usually concluded between the armistice and the final peace treaty. The treaty concluded between France and Germany on 26 February 1871 in the Hall of Mirrors at the Château de Versailles was only a preliminary treaty⁸⁹. It was confirmed a few months later by the Frankfurt Peace Treaty, the preamble to which states that the parties have agreed « to convert the preliminary peace treaty of 26 February of the current year into a definitive peace treaty »⁹⁰. The formal practice of preliminary peace treaties disappeared in the twentieth century. However, it is important to stress that this disappearance, far from calling into question the use of preparatory agreements, is replaced in contemporary practice by a proliferation of preparatory acts for the final agreement. The Washington Treaty between Israel and Egypt was preceded by a series of prior agreements between the parties, in particular the agreements concluded at Camp David a few months earlier⁹¹. The Treaty concluded in 1994 between Israel and Jordan was similarly preceded by a joint declaration on the principles of peace⁹². The Dayton Accords, for their part, follow on from a joint declaration and two series of fundamental principles agreed by common accord⁹³. The Algiers Agreement of 12 December 2000 between Eritrea and Ethiopia similarly refers to a framework agreement concluded in July of the same year⁹⁴. Because they are only preliminary, these treaties cannot be confused with the final treaty that they announce. They can only be included in the study as elements that may, if necessary, shed light on the text of the definitive treaties.

20. In the same way as preliminary treaties, treaties concluded after the conclusion of the peace treaty and relating to its implementation or modification must be excluded⁹⁵. This is the case, among countless others⁹⁶ , of the agreements concluded following the Treaty of Versailles of 1919, in particular concerning the adjustment of reparation mechanisms⁹⁷. Like the preparatory conventions, these instruments, which post-date the restoration of peace, should only be considered as tools to clarify the peace treaties that they complete or revise.

C. The peace treaty requires a conventional form

21. The final criterion for identifying peace treaties is purely formal in nature. Like the previous one, it is implied by the very object of the study: an analysis of the peace treaty is necessarily exclusive of all forms of return to peace that are not conventional between the parties, whether they operate unilaterally (1.) or spontaneously (2.).

1. The exclusion of unilateral forms of peacemaking

22. Contemporary international law no longer recognises the return to peace as a strictly inter-state prerogative. Indeed, some authors have argued that one of the necessary consequences of the mechanism established by the United Nations Charter was 

« the replacement of the traditional system of « peace treaties » concluded between victors and vanquished, by that of « international defence statutes » which it is up to the community of nations to impose on guilty states »⁹⁸.

It is true that such a view could be supported by the very terms of the Charter, Article 39 of which confers on the Security Council the power to adopt measures required to « restore international peace and security »⁹⁹. Some Security Council resolutions, in particular resolution 687 (1991) on Iraq, have been presented as constituting « for all practical purposes a peace treaty »¹⁰⁰ or at least a « substitute for a peace treaty »¹⁰¹. Although these resolutions generally seek the consent of the State they bind, formally they remain the unilateral acts of an international organisation¹⁰². They cannot therefore be classified as peace treaties. However, these instruments should not be ignored in this study. In fact, unlike treaties concluded in the absence of war or whose purpose is not to put an end to it, Security Council resolutions can be adopted in the same circumstances and have the same purpose as peace treaties. There is therefore a relationship, at least potential, of competition between the two categories of instruments. It will therefore be necessary to determine to what extent decisions by the Security Council and other international bodies are likely to replace or transform the practice of conventional peacemaking¹⁰³.

23. Other forms must also be excluded from the notion of a peace treaty. Firstly, there are the unilateral decisions that have sometimes been taken by certain States to re-establish peace in the absence of any agreement with the other belligerent¹⁰⁴. Secondly, there are agreements whereby the victors decide among themselves what to do with the vanquished after the war¹⁰⁵. This was the case with the agreements concluded between the main Allied powers at the end of certain conferences held during the Second World War, in particular the Potsdam Conference. While these agreements are of a conventional nature between the co-belligerents, for the vanquished they have the character of a res inter alios acta¹⁰⁶. In such a case, as Roberto Ago pointed out to the International Law Commission, « the obligations thus imposed on the aggressor State do not derive from the treaty as such and cannot be presented as effects of the treaty for a third State »¹⁰⁷. The obligation thus enacted, without necessarily being invalid, cannot be conceived of as a treaty obligation: from a practical point of view, it appears on the side of the vanquished as a unilateral act¹⁰⁸. These inter-allied agreements cannot therefore be counted as peace treaties either.

2. The exclusion of spontaneous methods of restoring peace

24. The last exclusion concerns all the procedures by which war ends between the parties independently of any recourse to a legal form – conventional or unilateral. This is the case, firstly, when the use of force leads to the annihilation of one of the belligerent states: the war is then extinguished at the same time as the vanquished. Post-war organisation is based solely on internal decisions by which the conqueror administers his new territory¹⁰⁹. This method is known in the literature as debellatio¹¹⁰. In this case, it is neither necessary nor possible to have recourse to a peace treaty¹¹¹.

25. The doctrine has also considered that peace is re-established spontaneously by the very fact of a prolonged cessation of hostilities¹¹². In this case, the belligerents remain but refrain from taking any steps – conventional or otherwise – to put an end to the war between them. This form is considered in doctrine to be « disadvantageous […], unseemly and disreputable »¹¹³. It is true that it leaves the relationship between the parties particularly uncertain, as regards both the past and the future. The phenomenon is all the more equivocal in that authors have sought to analyse it as a « tacit »¹¹⁴ or « indirect »¹¹⁵ agreement between the parties, subordinating the legal significance of the material cessation of hostilities to « [t]he interpretation of the will of the belligerents »¹¹⁶. The difficulties of such an undertaking ultimately led legal writers to conclude that « it is necessary to supplement the form of the de facto cessation of hostilities by an agreement concluded between the parties, and therefore by a peace treaty »¹¹⁷. Conflicts whose outcome has not been the subject of such an agreement are therefore not included in this study. 

*

26. This set of exclusions makes it possible to distinguish, within the very dense practice of return to peace, the instruments to which classical doctrine refers when it considers the notion of peace treaty. However, the corpus thus identified remains too vast and too heterogeneous to be approached in an analytical manner. Various methodological requirements combine to impose a stricter delimitation.

§ 2 Delimitation of the corpus

27. Gaston Bouthoul admits that eight thousand peace treaties have been concluded throughout history, over a period of more than four millennia and in a wide variety of places¹¹⁸. It is not possible to include all these treaties in the corpus considered in this study. Indeed, such a large volume of documents does not lend itself well to analysis. Such a study could only result in a sterile repertory or an excessively generalising presentation. Without falling into a nominalism hostile to all systematisation, it is necessary to reduce all the instruments studied to a number that allows us to consider both the whole and each of its parts. The means of this reduction are to be found in the methodological obstacles to an exhaustive study of practice. The most tangible obstacle is the accessibility of sources. Indeed, the legal study of peace treaties depends intimately on the analysis of their texts. However, the compilation of eight thousand instruments alone – even supposing it were possible¹¹⁹ – would probably be the work of a lifetime. Especially as it is not just a question of having the text of each treatise at hand: it also has to be translated, often from languages that are both ancient and exotic, with the loss of meaning that necessarily implies when new terms are superimposed on old ideas. This last remark touches on the most serious obstacle to an exhaustive analysis of the practice of conventional peacemaking. Indeed, the simultaneous analysis of all the peace treaties would pose an insurmountable problem of coherence of the corpus, since it would imply reducing to the same level profoundly different legal, political, social and cognitive systems. Such a process would be doubly flawed, simultaneously « anatopic and anachronistic, in the sense that it projects onto non-Western spaces or remote periods a way of looking at the human environment that is historically and geographically situated »¹²⁰. It is therefore imperative to delimit the corpus under study, both in time (A.) and space (B.).

A. Limits ratione temporis

28. This study considers only peace treaties concluded between 30 October 1648 – the date of the famous Treaties of Westphalia¹²¹ – and 12 December 2000 – the date of the Algiers Agreement between Eritrea and Ethiopia. This delimitation calls for two sets of explanations. 

The first relates to the reasons for including in the study treaties concluded in a period that might be thought to be of interest only to historians. The first reason is that many of the treaties concluded in the distant past are still in force today¹²². Studying the content of these instruments and the rules governing them is therefore not just a matter of historical curiosity. The study of these ancient instruments is also justified in that it allows us to break with an excessively ad hoc, if not casuistic, conception of an instrument that is often considered to be the sole product of circumstances. The historical approach, which tends to « consider an object of knowledge as the current result of a development that can be followed through history »¹²³ , makes it possible to consider the way in which the peace treaty was constructed as a legal technique. This hindsight makes it possible to identify certain regularities in practice that are incompatible with the mere capricious and contingent expression of the will of the victor. Finally, the historical approach makes it possible to point out the interactions between the peace treaty and general international law, of which it was both the instrument and the source. Randall Lesaffer emphasises the possibility of going « beyond the analysis of treaties as legal instruments to the analysis of peace treaties as sources of the law of nations »¹²⁴ and of simultaneously considering « the law which governs peace treaties – peace treaty law – and the law as it emerged from peace treaties »¹²⁵. His book, Peace Treaties and International Law, is based on the author’s conviction « that the study of peace treaties is an appropriate way to start a systematic research into the history of international legal practice »¹²⁶.

The second set of explanations relates to the reasons for not extending the study beyond the chosen period. There is no doubt that genuine peace treaties were signed well before the middle of the seventeenth century: the first peace treaties recorded by historians were concluded more than four thousand years ago. The Louvre Museum holds a « foundation nail » engraved with the text of a peace treaty concluded 2,400 years BC between « Entemena, the prince of Lagash, and Lugal-Kinishedudu, the prince of Uruk »¹²⁷. Internationalist doctrine often refers to the Treaty of Kadesh, concluded in 1259 BC between the pharaoh Ramses II and Khatisir, king of the Hittites¹²⁸. Numerous other instruments of this kind were concluded subsequently, in ancient Greece and Rome, during the Middle Ages and during the Renaissance. However, these treaties are not intended to be included in the corpus studied. Indeed, in terms of international relations, there are fundamental structural differences between each period¹²⁹.

It is true that some authors have specifically refuted the relevance of distinguishing treaties on the basis of the period in which they were concluded, arguing in particular that « [t]he distinction […] according to whether treaties were concluded before or after the Treaties of Westphalia […] is interesting for the historian, but not at all for the jurist »¹³⁰. However, it is difficult to equate modern international law, designed to govern relations between sovereign states, with its historical forms. On the one hand, the notion of state sovereignty has long been poorly established, with the result that for a long period « feudal man still considered himself a sovereign who could negotiate separately »¹³¹. On the other hand, the emerging state long retained a patrimonial character. Before the seventeenth century, « treaties are legally contracts between Princes and not between political entities. They are therefore, if we may put it this way, subject to the general regime of contract law »¹³². Legal historian Randall Lesaffer confirms that « no clear distinction existed yet between internal and international treaty practice […]. Peace treaties were formally not very different from private contracts. By consequences, the general rules of contract law […] applied to treaties »¹³³. As a result of these borrowings from different domestic laws, the practice of peace treaties was fragmented according to the States concerned¹³⁴ , and the same author considers more generally that « this dissimilarity of treaties is an indication of the absence of a truly European or general law of nations »¹³⁵. It was not until the seventeenth century that the jus publicum europaeum¹³⁶ was consolidated, destined to become, through successive integrations, contemporary international law¹³⁷. The Treaties of Westphalia are the symbol of this transformation in relations between the powers¹³⁸. It is therefore logical to take them as the starting point for our analysis¹³⁹. This choice also has the advantage of limiting the difficulties associated with the accessibility of sources. Indeed, while treaties had long been concluded and circulated in Latin, the second half of the seventeenth century was characterised by the widespread use of French as a diplomatic language. Above all, the treaties concluded since this period have been meticulously catalogued in large collections that are easily accessible to the jurist¹⁴⁰. Nevertheless, it is true that all these arguments apply essentially to treaties concluded on the European continent. Sources are much less accessible for ancient treaties concluded in other parts of the world. This difficulty, among others, imposes a restriction on the geographical scope of the study.

B. Limitations ratione loci

29. The present work is intended as a study of general international law. Accordingly, the corpus analysed includes, for the recent period, treaties concluded in different regions of the world, from the Horn of Africa¹⁴¹ to Central America¹⁴² , via the Near East¹⁴³ , the Balkans and Asia¹⁴⁴. However, this claim to universality diminishes the further back we go in time and confine ourselves to treaties concluded between European states. This is not to subscribe to a conception of international law that is solely centred on Europe: it is fully recognised that other civilisations have long developed international relations¹⁴⁵. On the contrary, the aim is to guard against the risk of projecting onto specific social relationships conceptions specific to European legal thought¹⁴⁶. Under the guise of universality, such a procedure would simply substitute one ethnocentrism for another. All the more so as access to sources in such a case presents real difficulties¹⁴⁷. Instead of a clumsy legal anthropology, it would be better to opt for a clear-cut delimitation. Non-European peace treaties will therefore be gradually included in the study, as it becomes possible to consider them, without obvious objection, in the light of the fundamental mechanisms of modern international law. 

*

30. This pruning, dictated by methodological imperatives, reduces the eight thousand peace treaties mentioned by Gaston Bouthoul to some two hundred instruments. While this represents only a tiny fraction of the total number of peace treaties, it does include virtually all the treaties concluded at the time and place in question.

§ 3. Issue, hypotheses and plan

22. Paul Amselek has criticised jurists for having lost their ability to marvel at the phenomena they observe¹⁴⁸. This is particularly true of studies of peace treaties. Curiously, authors have most often taken the technique of conventional return to peace for granted. And yet, without fear of incurring the wrath of the phenomenologists, we would willingly say that the peace treaty is astonishing in itself. Indeed, what is this treaty concluded under the duress of arms and therefore, if we are to believe the majority of the doctrine, in the absence of a genuine desire to commit oneself on the part of one of the parties¹⁴⁹ ? What is this treaty which, according to the same doctrine, enshrines rights and obligations that have no comparison on either side¹⁵⁰ ? What is a treaty that contains provisions that are disparate and materially unrelated to each other¹⁵¹ ? What is this treaty that some authors claim has remained unchanged since its inception, despite the considerable changes that have affected relations between the States¹⁵² ? What is this treaty that claims to subject to the will of a few issues that affect the security of international society as a whole¹⁵³ ? More fundamentally, what is this treaty – the perfect form of agreement – that originates in war – the extreme form of disagreement? Authors have rarely succumbed to astonishment at this paradoxical instrument: they have considered the peace treaty « with the already ingrained feeling that it is normal that it should exist »¹⁵⁴. What’s more, they have systematically disregarded the apparent contradictions in the peace treaty by purging it of certain data deemed incoherent. These partial analyses – focusing sometimes on the requirements of the form, sometimes on the specificity of the object – have led to contradictory conceptions of the phenomenon of the conventional return to peace (A.). – allows us to overcome the contradiction and grasp the complexity of the instrument (B).

A. Contradictory analyses of a paradoxical instrument

23. Authors have adopted resolutely contradictory positions with regard to the peace treaty. Some, indifferent to the various particularities of the instrument, have found no reason to exempt it from the ordinary law of treaties (1.). Others, on the contrary, considered it impossible to subject an instrument so far removed from the standard treaty model to the regime, or even to the very notion, of a treaty (2.).

1. The subordination of the peace treaty to the ordinary law of treaties

24. Academic writers have most often considered peace treaties solely in terms of the ordinary law of treaties. This view is basically based on a twofold assumption. The first, expressly accepted by the authors, is that of the unity of the law of treaties (a.). The second, which is both incidental and more problematic, is that of the exclusivity of its application (b).

a. The unity of treaty law 

25. A very large majority of legal writers support the view that 

« agreements between belligerents, although they clearly belong to the international law of war, do not obey special principles independent of those developed by the international law of peace. This will always be the general theory of international agreements »¹⁵⁵.

This unitary conception of the regime of international treaties is underpinned by the rejection, widely shared in doctrine, of a classification of treaties based on their subject-matter¹⁵⁶. More specifically, the refusal to distinguish between « named » and « unnamed » treaties precludes the consideration of a specific regime for peace treaties¹⁵⁷. In 1896, Alphonse Rivierwrote that « [t]he peace treaty is governed by the principles set out in the general theory of treaties »¹⁵⁸. In 1912, Ernest Nysruled in the same vein that « [t]he rules governing public agreements in general apply to peace treaties »¹⁵⁹. In 1964, Louis Delbez wrote that « [p]eace treaties obey the principles laid down by the general theory of treaties »¹⁶⁰. In 1968, Georg Schwarzenberger similarly considered that « [i]n law, no difference exists between peace treaties and any other type of consensual engagement. The same rules govern them all »¹⁶¹. In 1976, Alfons Klafkowski again noted that « [a]s an international agreement, the peace treaty is governed by the same rules of international law as other international agreements »¹⁶².

26. Only a few authors have considered, in the opposite direction, that the peace treaty should escape the ordinary law of treaties. These assertions are of very limited scope, both from a substantive and a historical point of view. From a substantive point of view, the specificity of the peace treaty is really reduced to the problem of defects in consent, and more specifically to the question of coercion. The title of the thesis defended in 1929 by Adnan Atassy is significant from this point of view: the author proposes to study Vices of consent in international treaties to the exclusion of peace treaties¹⁶³. From a historical point of view, this derogatory conception of the peace treaty regime can be explained by the progressive evolution of doctrine with regard to coercion. For a long time, the general acceptance of the validity of treaties concluded under duress made it unnecessary to have recourse to a separate regime for peace treaties: these were purely and simply subsumed under the general rule. The removal of peace treaties from the ordinary law was above all a way for authors in favour of the nullity of treaties concluded under duress to moderate certain consequences of their doctrine, which were then considered unrealistic¹⁶⁴. Thus, the specificity of the peace treaty was seen by its proponents as merely transitory, destined to fade as the idea of the nullity of treaties concluded under duress gained ground. Any differences of opinion in the doctrine as to the subordination of the peace treaty to the ordinary law of international treaties did not therefore concern the idea of an irreducible incompatibility between the concept and its regime: on the contrary, authors agreed that the law of treaties was the appropriate framework for analysing the peace treaty.

b. The exclusivity of treaty law

27. All the judgements made on the legal regime of the peace treaty reveal that authors commonly subscribe to the hypothesis that the peace treaty is governed exclusively by the law of treaties. The peace treaty is always subject to « the general theory of international agreements »¹⁶⁵ , to « the principles set out in the general theory of treaties »¹⁶⁶ , to « the rules governing public agreements in general »¹⁶⁷ or to « the principles laid down by the general theory of treaties »¹⁶⁸. Implicit in this is the idea that, from the point of view of its regime, a peace treaty is an international agreement that is indifferent to the requirements that may result from bodies of rules other than the law of treaties, or from circumstances other than the mere agreement of wills. The consequence of this narrowly voluntarist conception of the peace treaty is one that legal writers found increasingly difficult to accept from the end of the First World War: « international law sets no limit to the conditions of peace which the victor may exact from a defeated enemy »¹⁶⁹. Hence a series of doctrinal reactions designed to temper the excesses of a mechanism too closely subordinated to will.

2. The irreducibility of the peace treaty to the notion of a treaty

28. Some authors radically questioned the voluntary nature of the peace treaty, and reclassified it as a unilateral act addressed to the defeated state. This approach took two very different forms. In the first case, the treaty nature of the peace treaty is denied on the grounds of defects in the expression of the will of the defeated state: the peace treaty is then conceived as a unilateral act emanating from the victors, whose authority rests solely on the military victory (a.). In the second case, the conventional nature of the peace treaty is called into question, not because the will is lacking, but on the contrary because, in view of the purpose of the peace treaty, it should not be required. The peace treaty is then conceived as a unilateral act emanating from a de facto international government acting on behalf of the international community as a whole (b.).

a. Disqualification based on lack of willpower

29. Noting the infringement of the will of the defeated state when peace treaties were concluded, many authors took the view that this instrument could not be considered a genuine treaty. Noting that one of the parties is able to impose its will on the other, Georges Scelle considers that « [the] peace ‘treaty’ […] was only contractually fictitious in appearance »¹⁷⁰. More generally, the author considers that treaties concluded in the absence of an authentic will on the part of each of the parties are only the subject of a « contractual prejudice »¹⁷¹ ; in reality, « [i]t is a question here, let us repeat, of legislation and not of contract »¹⁷². James‑ Leslie Brierly similarly considers that a treaty imposed by violence 

« In essence, it is not contractual at all, but constitutes a legal instrument of an entirely different kind. For in contractual form, the transaction we are seeking to analyse boils down to this: a new legal situation, involving new rights and new duties for both parties, is imposed on the weaker state by the stronger. The consent of the former is only formal, not genuine, and the nature of the transaction is legislative, not contractual« ¹⁷³.

Jean-Pierre Ritter takes the almost identical view that « the contractual form that an imposed regulation may take does not alter […] the nature of the regulation itself, which remains a unilateral proclamation »¹⁷⁴. Giorgio Balladore-Palliericonsiders more specifically the case of some of the peace treaties concluded at the end of the Second World War, which « are called treaties and retain their external appearance »¹⁷⁵ , but whose conditions of entry into force lead one to consider that « [i]t is no longer a bilateral act, but a unilateral act enacted by the victors »¹⁷⁶. Jean-Paul Jacqué, for his part, considers that « not all unilateralism is […] absent from these peace treaties » and describes them as « mixed acts »¹⁷⁷. Some contemporary authors still subscribe to the concept initiated by Georges Scelle, believing that a peace treaty is an « act which is […] conventional in appearance only »¹⁷⁸. This view, based on the observation that the will expressed by the victor is flawed, is similar to another view, albeit with very different premises.

b. Disqualification based on indifference to the will

30. The disqualification of the peace treaty with regard to the concept of convention does not result solely from a concern to protect the will of the defeated State. Some writers have reached the same conclusion, observing that the will is simply not a relevant factor in the analysis of a peace treaty. Authors gradually came to the view that « sanctions and measures of international security, as well as reparation for such violations, cannot, as a matter of principle, be subject to the consent of the guilty party »¹⁷⁹. The gradual emergence of an organised international society « rules out the possibility that the end of war may, as in the past, take the form of a ‘conventional’ act »¹⁸⁰. Authors of various legal conceptions commonly subscribe to the idea that peace treaties are incompatible with the « new international law »¹⁸¹. Georges Scelle considers that the prohibition of the use of force « logically implies […] the disappearance of the ‘peace treaty' »¹⁸². Hans Kelsen also admits that if « war is held to be an unlawful act in international law, the idea of a peace treaty becomes problematic »¹⁸³ , if not « absurd »¹⁸⁴. This time, the treaty form is condemned not out of respect, but rather out of distrust of the will¹⁸⁵.

*

31. These initial observations lead to two observations. The first is the diversity of doctrinal conceptions: diversity as to the applicable rules, on the one hand, with the peace treaty oscillating between the ordinary law of treaties and the sui generis competence of de facto bodies designated by the victory; diversity as to the concerns, on the other hand, with the return to peace floating between the defence of a voluntarism concerned with the integrity of the will of States and the promotion of an objectivism indifferent to consent. The second observation is that these different conceptions are incompatible: the supporters of the conventional form, attached to formalism, have most often shown themselves indifferent to the specific nature of the purpose and issues of the peace treaty, while its opponents have cheaply abandoned a conventional form that is firmly rooted in practice. This opposition between formalism and substantialism only sheds partial light on the peace treaty, ignoring, in both cases, certain fundamental aspects of the instrument’s physiognomy. It is therefore important to move beyond this opposition by seeking to reconcile the opposing imperatives of form and purpose. 

B. Reconciling the conflicting requirements of a complex instrument

32. Denouncing the contradictory conceptions of doctrine with regard to the Peace Treaty in no way implies questioning the value of each type of analysis. On the contrary, overcoming the contradiction implies taking careful note of its different terms. Proponents of voluntarism are right to see the peace treaty as a conventional act. Similarly, supporters of objectivism are justified in considering that, when peace is restored, there exists in the international legal order a set of prescriptions that govern the behaviour of the parties independently of, or even against, their will. Overcoming doctrinal opposition therefore implies considering the peace treaty as a conventional act (1.) subordinate to the requirements of international law (2.).

1. The peace treaty: a conventional act

33. It is true, as one author points out, that « one might sometimes doubt that conventions can be concluded between belligerents, i.e. that the reciprocal violence of the subjects is at some point replaced by peaceful negotiation »¹⁸⁶. Nevertheless, the reclassification of the peace treaty as a unilateral or even legislative act is not convincing¹⁸⁷. While recourse to a treaty between belligerents who have fought each other in blood may come as a surprise, it is nonetheless necessary to take note of a contradiction that has long been accepted in practice. States have always regarded peace treaties as genuine conventions. The rare attempts to disqualify peace treaties have met with a very clear refusal on the part of international courts¹⁸⁸. The peace treaty must therefore be considered, rigorously, as a genuine international treaty. It is worth remembering in this respect that the Latin word for peace « Pax, from Pango, means convention, and is the same word as pact »¹⁸⁹. A return to peace cannot therefore be considered as manifestly irreducible to the notion of a treaty.

2. The peace treaty: a conventional act subordinate to international law

34. While critics of the treaty form have gone too far in seeking to recharacterise the peace treaty as a unilateral act imposed on the vanquished, they have been right to point out – something that the voluntarists may have forgotten in an opposite excess – that States, when they re-establish peace, are not freed from the rules governing international relations. Peace treaties are not the ethereal product of the pure will of parties in a state of legal weightlessness. On the contrary, it is historically situated, enmeshed in a web of factual and normative data that simultaneously determines its form and content. A full explanation of the peace treaty presupposes taking note of its simultaneous subordination to several bodies of rules (a.), which combine dynamically to determine its regime (b.).

a. A treaty subject to several sets of rules at the same time

35. Although fundamentally opposed in their conclusions, the various doctrines relating to the peace treaty converge in some of their premises. In particular, their proponents agree in considering the peace treaty, conceived as an international treaty, solely in the light of the law of treaties¹⁹⁰. Curiously enough, almost all the authors seem to subscribe to a strictly voluntarist conception of an instrument considered to be impervious to the objective requirements of international law. And yet, by its very purpose, the return to peace falls within the scope of many other bodies of rules. Authors hostile to the treaty form have not failed to emphasise the links between the return to peace and the law of collective security¹⁹¹. Other authors – outside the debate on the nature of the peace treaty – have also shown that the mechanisms of the law of responsibility are not absent when peace is restored¹⁹². More generally, when concluding a peace treaty, States are in principle bound by all the rules applicable to any of the areas covered by the treaty: human rights¹⁹³ , humanitarian law¹⁹⁴ , law of succession of States¹⁹⁵ , law of peoples¹⁹⁶and minorities¹⁹⁷ , private international law¹⁹⁸ , etc. The rules concerned cannot be identified generally and a priori.They depend on the specific circumstances of each conflict. 
36. The peace treaty cannot therefore be considered as a pure act of will: the instrument must deal with certain requirements that pre-exist the will of the parties and contribute to its formation. Such a hypothesis, in that it considers simultaneously the voluntary and the obligatory, makes it possible to account for certain aspects of peace treaties that are quite incomprehensible from the point of view of the theory of the autonomy of the will. As a purely voluntary state, it cannot consent to obligations such as territorial amputation, a drastic reduction in its armed forces or the payment of large sums of money. The reason for this consent is then sought by the doctrine in the violence suffered by the vanquished debtor. However, such an explanation is neither historically nor theoretically satisfactory. The agreed opposition of an all-powerful victor to a vanquished with no alternative but submission or annihilation does not correspond well with practice¹⁹⁹. Similarly, the explanation of the treaty by the manifestation of the greatest strength – even if it could adequately explain the acceptance by the vanquished of the conditions imposed on it – does not account for either the elaboration of these conditions by the victor, or the relative moderation that the latter often displayed in reality²⁰⁰. The hypothesis of the conjunction of bodies of rules makes it possible to go beyond the limits of an analysis contained in the law of treaties alone, by looking beyond the will of the parties alone for the basis of the obligations incorporated in the treaty. The subordination of the peace treaty to different bodies of rules not only provides a basis for its content: it also makes it possible, in the opposite direction, to account for certain specific features of its regime. 

b. A system resulting from the combination of several sets of rules

37. To consider the peace treaty in the light of the different bodies of rules governing its conclusion means that we must immediately abandon the idea of understanding its regime as a static, prior and coherent set of rules specific to this instrument. On the contrary, this system results from the conjunction, as it were, of rules that are essentially unrelated. The product of the dynamic articulation of the requirements of various bodies of rules, it must be conceived as a complex legal regime, i.e. « [c]omposed of elements which maintain numerous, diverse relationships, difficult to grasp in the mind, and often presenting different aspects »²⁰¹ , « a system […] of distinct elements, organised by defined relationships »²⁰². This approach, which consists of studying the way in which the bodies of rules involved in peacekeeping and peacemaking interact, is not new. Major works have recently been devoted to studying the relationship between the law of war and the law of responsibility²⁰³ or between the law of responsibility and the law of collective security²⁰⁴. From a similar perspective, this study seeks to analyse the interactions between the main bodies of rules governing the return to peace and the law of treaties. 

The existence of such relationships is clearly suggested by certain provisions of the 1969 Vienna Convention, which admit that considerations outside the law of treaties may be the basis for infringements, sometimes considerable, of ordinary law. Article 52’s reference to the « principles of the Charter of the United Nations » to modulate the effects of the rule on military coercion is only a minimal illustration of the consequences that the law of collective security may have on the law of treaties²⁰⁵. Articles 73 and 75 authorise derogations with a much wider scope, capable of rendering inoperative all the guarantees provided by the law of treaties where, in particular, questions are at issue relating to the responsibility of a State²⁰⁶ or to the aggression it has committed²⁰⁷. These bridges between the different branches of law make it both possible and necessary to analyse peace treaties by combining the requirements of the law of treaties with those of other bodies of law. They thus make it possible to overcome doctrinal contradictions based on the irreducible opposition between treaty form and its object, and more generally between the voluntary and the obligatory.

C. Study plan

38. The study of the interactions between the form and the object of the peace treaty – to put it another way, between the act and the norm²⁰⁸ , between the mode of production and the product²⁰⁹ – presupposes a precise evaluation of practice with regard to each of these aspects. Indeed, doctrine has often paid only distracted attention to the content of peace treaties²¹⁰. This indifference has resulted in a sometimes exaggerated representation of their provisions and the reasons for them. This distorted perception of the respective rights and obligations of the parties contributed to an excessively unequal conception of a treaty, which could only be explained by coercion. A detailed examination of the purpose of the peace treaty is therefore a priority, insofar as it will then make it possible to dispel certain prejudices relating to the nature and regime of the instrument. In this sense, taking note of the singularity of the subject-matter of the peace treaty (Part I) not only makes it possible to dispel a certain number of the hesitations maintained by doctrine as to the form of the instrument (Part II), but also to highlight the mechanisms which ensure that the treaty form corresponds to its subject-matter (Part III).

Notes

1 H. Kelsen, « Théorie du droit international public », R.C… [34 words hidden]

2 Quoted in F. Przetacznik, « A Definition of Peace », Sri Lanka… [31 words hidden]

3 Vattel, Le droit des gens, ou principes de la loi naturelle,… [68 words hidden]

4 S. von Pufendorf, Le droit de la nature et des gens,… [61 words hidden]

5 H. Kelsen, « Theory of Public International Law », op. cit… [20 words hidden]

6 As one author points out, « [t]he picture which emerges from… [148 words hidden]

7 For a classic overview of the different conceptions, see e.g…. [56 words hidden]

8 L. Delbez, « La notion juridique de guerre », R.G… [28 words hidden]

9 For some examples borrowed from French practice and from different periods: « Treaty… [132 words hidden]

10 Treaty of Guadalupe Hidalgo, 1848 (United States of America; Mexico)…. [54 words hidden]

11 The text of this treaty, concluded on 16 May 1832, is reproduced… [55 words hidden]

12 On this provision, see below, n^os 57 et seq.

13 Emphasis added.

14 Emphasis added.

15 Article 2 common to the four Geneva Conventions of 12 August 1949.

16 P.T.I.Y., app, Prosecutor v. Duško… [46 words hidden]

17 The press sometimes considered that Ethiopia had made such a declaration (see J… [111 words hidden]

18 J. A. S. Collin de Plancy, Fastes militaires des Belges… [98 words hidden]

19 Border incidents are often settled by less formal mechanisms, sometimes provided for in… [79 words hidden]

20 Treaty of Peace and Friendship, concluded on 29 November 1984 in Vatican City… [39 words hidden]

21 This is reflected in the wording of the first article of the treaty,… [35 words hidden]

22 Treaty of Beijing, signed on 12 August 1978 between China and Japan,… [39 words hidden]

23 Beijing Joint Communiqué, 1972 (Japan; People’s Republic of China), pt… [18 words hidden]

24 Statement of 25 July 1994, annexed to the letter of 5 August 1994… [54 words hidden]

25 In this regard, see R. Kuete-Minga, « Le traité… [51 words hidden]

26 Declaration of 25 July…, supra, pt. C, para. 1… [19 words hidden]

27 Treaty of Wadi Araba, 1994 (Israel; Jordan), art. 1… [16 words hidden]

28 Ibid, art. 2.

29 On the question of terminological indifference in the law of treaties, see the… [126 words hidden]

30 A. Rivier, Principes du droit des gens, Rousseau, Paris,… [21 words hidden]

31 The practice also appears to be well established in French constitutional law, as evidenced… [29 words hidden]

32 C. Bell, On the Law of Peace – Peace Agreements and the… [26 words hidden]

33 J.-Y. de Saint-Prest, Histoire des traités de paix… [49 words hidden]

34 C. Bell, « Contemporary Peace Agreements and Accords », in N…. [48 words hidden]

35 See typically C. Stahn, « Jus Post Bellum: Mapping the Discipline… [146 words hidden]

36 On this question, see the remarks of M. G. Kohen,… [79 words hidden]

37 The International Law Commission emphasized in its commentary that the restrictive definition in art… [78 words hidden]

38 As Antonio Cassese writes about Article 3 common to the four Geneva Conventions… [126 words hidden]

39 C. Bell, « Peace Agreements: their Nature and Legal Status »,… [51 words hidden]

40 The notion of partial legal order is used here in a sense that varies… [78 words hidden]

41 C. Bell, On the Law of Peace, op. cit…. [22 words hidden]

42 T.S.S.L., app, The Prosecutor against Morris… [126 words hidden]

43 The authors have not failed to note the variations between the different lists used… [53 words hidden]

44 E. Jouannet, « Le règlement de paix entre l’Éthiopie et l’Érythrée :… [74 words hidden]

45 C. Bell, On the Law of Peace..., p. 9.

46 On the appropriate place to designate these agreements, which were the subject of… [69 words hidden]

47 T. Meron, « Classification of Armed Conflict in the Former Yugoslavia:… [39 words hidden]

48 Application of the Convention on the Prevention and Punishment of the Crime of Genocide… [82 words hidden]

49 Unless otherwise indicated, « Vienna Convention » refers to the Convention on Treaties between… [47 words hidden]

50 It should be noted that these questions relating to the Dayton Accords are by… [170 words hidden]

51 This approach is not unrelated to the solution adopted by the Court in the… [198 words hidden]

52 The plural is necessary here, as the United States of America was still… [55 words hidden]

53 On the recognition of states contained in peace treaties, see below, n… [20 words hidden]

54 The « Evian agreements » of 18 March 1962 actually refer to a number… [70 words hidden]

55 The various versions published at the time were inconsistent in this respect. The… [117 words hidden]

56 Conclusion of the Evian talks, document no.^o 1, « Conditions… [22 words hidden]

57 Ibid, document no. 1-a.^o 

58 Ibid. document no.^o 1-b, art. 24.

59 Ibid. document no.^o 1-b, art. 24 (… [18 words hidden]

60 Ibid, document no.^o 3, preamble, para. 4 (… [18 words hidden]

61 This conclusion, limited solely to the categories of international law, in no… [128 words hidden]

62 On the Oslo Accords of 13 September 1993, see. N. K… [271 words hidden]

63 See e.g. R. Lapidoth, N. K. Calvo… [259 words hidden]

64 Unesco General Conference, Resolution 36C/15 (in Proceedings of the Unesco… [35 words hidden]

65 U.N.G.A., Resolution 67/19, 29… [42 words hidden]

66 U.N.G.A., Resolution 65/16, 30… [105 words hidden]

67 R. Monaco, « Les conventions entre belligérants », R.C…. [33 words hidden]

68 S. von Pufendorf, Le droit de la nature et des gens,… [39 words hidden]

69 Wolff, Principes du droit de la nature et des gens, translated by… [49 words hidden]

70 A. Rivier, Principes du droit des gens, op. cit…. [25 words hidden]

71 H. Kelsen, « Theory of Public International Law », op. cit… [20 words hidden]

72The fact that the First World War only ended on 10 January 1920, the… [96 words hidden]

73 For a quantitative assessment of this practice, see^os. 305-… [17 words hidden]

74 On the distinctions between different categories of instruments, see in particular M…. [868 words hidden]

75 Convention des tuileries of 23 April 1814 between France and the Allied Powers,… [51 words hidden]

76 M. Sibert, « L’armistice », op. cit. p. 658… [91 words hidden]

77 On this question, see in particular R. Monaco, « Les conventions… [101 words hidden]

78 General Armistice Agreement between Egypt and Israel, 24 February 1949, U…. [65 words hidden]

79 M. Sibert, « L’armistice », p. 662.

80 On this question, see in particular N. Feinberg, « The Legality… [100 words hidden]

81 Martens, Nouveau Recueil général de traités, 3^e series, Theodor Weicher,… [42 words hidden]

82 General Armistice Agreement between Egypt and Israel, 24 February 1949, art…. [21 words hidden]

83 Ibid, art. 1.

84 Shabtaï Rosenne refers to a practice of « converting the armistices into embryonic peace… [52 words hidden]

85 Egyptian-Israeli Agreement on the Disengagement of Forces, 18 January 1974,… [74 words hidden]

86 Algiers Agreement, 2000 (Eritrea; Ethiopia), art. 1, para… [18 words hidden]

87 The text of this agreement is reproduced in the annex to the letter of… [43 words hidden]

88 Not bound by the strict terms of the definition of a peace treaty,… [152 words hidden]

89 Preliminary Treaty of Versailles, concluded on 26 February 1871 between Germany and France… [48 words hidden]

90 Treaty of Frankfurt, 1871 (Germany; France), preamble.

91 Treaty of Washington, 1979 (Egypt; Israel), preamble. For the… [218 words hidden]

92 Washington Declaration, 25 July 1994 (the text of the Declaration is annexed… [57 words hidden]

93 The joint declaration adopted in Geneva on 8 September 1995 was accompanied by a… [145 words hidden]

94 Algiers Agreement, 2000 (Eritrea; Ethiopia), preamble.

95 For a historical overview of such agreements, see. É. Darras, Étude… [27 words hidden]

96 See, by way of pure illustration, the treaty concluded in 1928 between… [201 words hidden]

97 On the agreements on reparations, from London to Lausanne, see P…. [79 words hidden]

98 V. Pella, « Fonctions pacificatrices du droit pénal supranational et fin du… [60 words hidden]

99 Charter of the United Nations, art. 39. See also Articles 42… [104 words hidden]

100 R. Zacklin, « Les Nations Unies et la crise du Golfe »,… [45 words hidden]

101 S. Sur, « Sécurité collective et rétablissement de la paix : la… [59 words hidden]

102 This is in particular the position of S. Sur, « Sécurité collective… [98 words hidden]

103 On this question, see below, pp. 693-734.

104 On this practice, see the examples listed by H. Dorandeu… [163 words hidden]

105 This hypothesis was explicitly considered by the International Law Commission during the debates preceding… [131 words hidden]

106 In his course on the effects of treaties on third parties, Philippe Cahier… [134 words hidden]

107 Speech by Mr Ago, 853^e session, Ann. C.D…. [33 words hidden]

108 This assimilation of a treaty imposing obligations on third parties to a unilateral act… [267 words hidden]

109 On this aspect, see the Judgment of the International Court of Justice in… [52 words hidden]

110 On debellatio, see below, speculative n ^os697-698.

111 On this question, see by way of illustration H. Kelsen… [49 words hidden]

112 On this question, see in particular C. C. Tansill, « … [61 words hidden]

113 A. Klafkowski, « Les formes de cessation de l’état de guerre… »,… [56 words hidden]

114 A. Klafkowski, « Les formes de cessation de l’état de guerre… »,… [23 words hidden]

115 H. Dorandeu, La fin de l’état de guerre sans traité de paix… [26 words hidden]

116 Ibid, pp. 408456‑.

117 A. Klafkowski, « Les formes de cessation de l’état de guerre… »,… [23 words hidden]

118 G. Bouthoul, Huit mille traités de paix, R. Julliard,… [70 words hidden]

119 Peace treaties did not always take the documentary form we know today: « in… [86 words hidden]

120 L. Boltanski, Énigmes et complots : une enquête à propos d’enquêtes,… [25 words hidden]

121 This name, sometimes used in the singular, actually conceals two treaties:… [69 words hidden]

122 On this issue, see the comments made above, n. ^o8.

123 A. Lalande, Vocabulaire technique et critique de la philosophie, 10^e ed… [35 words hidden]

124 R. Lesaffer (ed.), Peace Treaties and International Law..., op…. [21 words hidden]

125 Ibid.

126 Ibid, p. 3. Yoram Dinstein notes in the same vein that… [52 words hidden]

127 Musée du Louvre, Department of Oriental Antiquities, Richelieu wing, room 1a… [51 words hidden]

128 See e.g. P. Guggenheim, « Contribution à l’histoire des… [76 words hidden]

129 For example, on the possibility of glimpsing Rome’s international relations through the idea… [80 words hidden]

130 H. Kraus, « Système et fonction des traités internationaux », R…. [35 words hidden]

131 J. Michelet, Histoire de France, Hachette, Paris, 1837,… [23 words hidden]

132 G. Lewkowicz, « Le traité international comme figure du contrat : le… [83 words hidden]

133 R. Lesaffer, « Peace Treaties from Lodi to Westphalia », in R… [50 words hidden]

134 Ibid, p. 15: « in the sixteenth and early seventeenth centuries… [41 words hidden]

135 Ibid.

136 By this he means « the European system of states, consolidated by the… [117 words hidden]

137 Antonio Truyol y Serra, admits that European public law « was the matrix… [65 words hidden]

138 In this regard, see G. Berlia, « Remarques sur la paix… [38 words hidden]

139 This in no way calls into question the idea that « Peace Treaties of… [51 words hidden]

140 Historians nevertheless warn against the uncertainty surrounding the compilation of both texts and collections… [143 words hidden]

141 Algiers Agreement, 2000 (Eritrea; Ethiopia).

142 Treaty of Lima, 1980 (El Salvador; Honduras).

143 Treaty of Washington, 1979 (Egypt; Israel) and Treaty of Wadi… [23 words hidden]

144 Paris Agreement, 1973 (United States of America; Democratic Republic of Vietnam… [16 words hidden]

145 See e.g. J. A. Cohen, « Ethnocentrism and… [131 words hidden]

146 As the historian John Keegan notes, « Clausewitzian warfare did not serve… [41 words hidden]

147 An illustration of these difficulties appears in the footnote to one of the volumes… [111 words hidden]

148 P. Amselek, « L’étonnement devant le droit », A.P…. [27 words hidden]

149 Georges Ténékidès writes that « [o]ne cannot deny […] that peace treaties… [98 words hidden]

150 Emmanuel Decaux and Olivier de Frouville write in this regard that « [b]… [90 words hidden]

151 It is true, as Paul Reuter has noted, that « most… [149 words hidden]

152 A. Klafkowski, « Les formes de cessation de l’état de guerre… »,… [151 words hidden]

153 On this question, see infra, n ^o648.

154 To hijack a phrase that Paul Amselek applies, not to the peace treaty… [42 words hidden]

155 R. Monaco, « Les conventions entre belligérants », op. cit…. [19 words hidden]

156 The classification based on the subject matter governed by the treaty is in fact… [70 words hidden]

157 On this distinction, see P. Reuter, Introduction au droit des traités… [61 words hidden]

158 A. Rivier, Principes du droit des gens, op. cit…. [25 words hidden]

159 E. Nys, Le droit international – les principes, les théories,… [26 words hidden]

160 L. Delbez, « La fin de la guerre et le droit des… [40 words hidden]

161 G. Schwarzenberger, « Peace Treaties before International Courts and Tribunals », Ind… [32 words hidden]

162 A. Klafkowski, « Les formes de cessation de l’état de guerre… »,… [47 words hidden]

163 A. Atassy, Les vices de consentement dans les traités internationaux à l’exclusion… [34 words hidden]

164 On the diversity of doctrinal conceptions with regard to the validity of peace treaties… [30 words hidden]

165 R. Monaco, « Les conventions entre belligérants », op. cit…. [19 words hidden]

166 A. Rivier, Principes du droit des gens, op. cit…. [25 words hidden]

167 E. Nys, Le droit international – les principes, les théories,… [26 words hidden]

168 L. Delbez, « La fin de la guerre et le droit des… [25 words hidden]

169 H. Lauterpacht, « The Limits of the Operation of the Law of… [37 words hidden]

170 G. Scelle, « Quelques réflexions sur l’abolition de la compétence de guerre… [98 words hidden]

171 G. Scelle, « Règles générales du droit de la paix », R… [36 words hidden]

172 Ibid, p. 447 (emphasis added). 

173 J.-L. Brierly, « Règles générales du droit de la paix… [41 words hidden]

174 J.-P. Ritter, « Remarques sur les modifications de l’ordre international… [38 words hidden]

175 G. Balladore-Pallieri, « La formation des traités dans la pratique… [40 words hidden]

176 Ibid. The author refers more specifically to the peace treaties concluded in 1947… [36 words hidden]

177 J.-P. Jacqué, Éléments pour une théorie de l’acte juridique en… [35 words hidden]

178 M. Sinkondo, Droit international public, Ellipses, Paris, 1999,… [19 words hidden]

179 V. Pella, « Peacemaking functions », op. cit. p…. [20 words hidden]

180 G. Scelle, « Quelques réflexions sur l’abolition de la compétence de guerre… [24 words hidden]

181 See already in this sense E. E. F. Descamps, « … [54 words hidden]

182 G. Scelle, « Quelques réflexions sur l’abolition de la compétence de guerre… [24 words hidden]

183 H. Kelsen, « Theory of Public International Law », op. cit… [20 words hidden]

184 Ibid, p. 57.

185 For a fuller account of these doctrinal conceptions, see^os. 649… [20 words hidden]

186 R. Monaco‑, « Les conventions entre belligérants », op. cit…. [21 words hidden]

187 Hart had already greeted the argument with scepticism: « it has been claimed… [115 words hidden]

188 See the contradictory and unsuccessful positions of France, Italy and the United States… [40 words hidden]

189 A. Rivier, Principes du droit des gens, supra, t…. [45 words hidden]

190 On this point, see the comments made above, n. ^o36.

191 On this aspect, see the discussion below, not. ^os198 et seq… [21 words hidden]

192 See especially the extensive discussion of this issue in P. d’Argent, Les… [35 words hidden]

193 On this question, see C. Bell, Peace Agreements and Human Rights… [19 words hidden]

194 On this aspect, see the summary and references provided by P. d’Argent… [31 words hidden]

195 See e.g. C. Phillipson, Termination of War and Treaties… [34 words hidden]

196 On this question, see the discussion below, at. ^os670-674… [16 words hidden]

197 For recent considerations on this question, see in particular G. Hamza,… [72 words hidden]

198 See for a specific illustration of problems of this kind E. J…. [168 words hidden]

199 In this sense, see P. R. Pillar, Negotiating Peace:… [65 words hidden]

200 On this point, see the discussion of the equality of benefits in the… [29 words hidden]

201 C.N.R.S., Trésor de la Langue Française,… [40 words hidden]

202 A. Lalande, Vocabulaire technique et critique de la philosophie, above,… [22 words hidden]

203 P. d’Argent, Les réparations de guerre..., aforementioned, 902 p.

204 M. Forteau, Droit de la sécurité collective et droit de la responsabilité… [28 words hidden]

205 Vienna Convention, art. 52: « [e]very treaty is void… [45 words hidden]

206 Vienna Convention, art. 73: « [t]he provisions of the… [71 words hidden]

207 Vienna Convention, art. 75: « [t]he provisions of the… [71 words hidden]

208 On this distinction, see P. Reuter, « The Operational and Normative… [167 words hidden]

209 According to the distinction made by Florence Poirat in the title of her thesis… [47 words hidden]

210 On this statement, see infra, n ^o49.