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The Oxford Guide to Treaties edited by Hollis, Duncan B (1st July 2012)

s.III Treaty Application, 16 State Succession in Respect of Treaties

Gerhard Hafner, Gregor Novak

From: The Oxford Guide to Treaties

Edited By: Duncan B. Hollis

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2015. All Rights Reserved. Subscriber: null; date: 21 November 2019

State succession, international agreements — Vienna Convention on the Law of Treaties — Secession

(p. 396) 16  State Succession in Respect of Treaties


In a generally accepted definition that is also enshrined in the 1978 Vienna Convention on Succession of States in Respect of Treaties (VCSST), State succession is conceived as the ‘replacement of one State by another in the responsibility for the international relations of territory’.1 The legal regime governing State succession is significant because no new State or territory can exist outside the legal order of the community of States. In order to avoid jeopardizing predictability and stability—the central objects of international law—it is necessary to regulate the legal status and acceptance of new States as well as other alterations in the responsibility for the international relations of territory within this community. Consequently, the regulation of treaty relations in cases of State succession (‘treaty succession’) is widely acknowledged to be a critical question for international relations and international law. The law and practice of State succession is highly contextual, with the outcome of each case strongly influenced by the relevant political situation. As a result, there is no single rule for all cases of treaty succession. Nonetheless, for certain cases general rules and practices can be identified that may serve as a guide for future cases related to succession, even if they may not prove truly determinative.

Legal problems associated with State succession have arisen since ancient times.2 In the modern era of sovereign States, early notable cases included the unifications of Germany3 and Italy,4 the transfers of Alsace and Lorraine,5 the emergence of the United States of America6 (US), and the independence of colonies in Latin (p. 397) America.7 The First World War raised a new wave of related problems with the break-up of the Austro-Hungarian Empire,8 the dissolution of the Ottoman Empire,9 and the emergence of new States on the territory of Tsarist Russia resulting from its eventual transformation into the Union of Soviet Socialist Republics (USSR).10

A further important source for the law and practice of State succession emerged from the period of European colonialism.11 The process of decolonization in the period after the Second World War was particularly significant, both in quantitative terms and in terms of its impact on international relations.12 UN membership rose from 50 in 1945 to over 190 today largely due to this process.13 Decolonization also provided the relevant political context within which the International Law Commission (ILC) formulated draft articles on State succession in respect of treaties, leading up to the 1978 VCSST.14 The VCSST, however, came relatively late in the decolonization process. The wave of newly emerging States receded soon thereafter, and for a time, the question of State succession seemed to become less significant in international relations and international law.15

Prior to 1989, therefore, it was widely assumed that the system of existing States (particularly in Europe) was unlikely to change due to the then existing East-West stalemate.16 The end of the Cold War and the breakdown of the communist system dramatically changed that situation in Europe and Central Asia. Germany incorporated the former German Democratic Republic (GDR), the Baltic States, liberated from the iron clamp of the Soviet system, gained independence and other former Union Republics of the USSR followed. At about the same time, (p. 398) the Socialist Federal Republic of Yugoslavia (SFRY) collapsed in the midst of war and eventually opened the door to the creation of, so far, six or even seven new States.17 Finally, the Czechoslovak Federative Republic (CSFR) (formerly the Czechoslovak Socialist Republic (CSSR)) peacefully dismembered into two new States: the Czech and the Slovak Republics. Outside the European context, the new State of East Timor seceded from Indonesia after several decades of occupation. This new wave of emerging States imbued the issue of State succession with new significance, especially given the legal problems flowing from the density of pre-existing relations among affected States.18

Although this latest and seemingly last major wave of State succession is largely over, legal problems of treaty succession remain relevant. Growing cross-border activities of States and non-State actors have created a need for greater stability and predictability, leading to an even greater density of treaty relations among States and in relation to international organizations (IOs). Future cases of State succession seem likely, if not inevitable, such as the case of the recent independence of South Sudan.19 These cases will occur under varying circumstances and entail different legal problems and solutions. In the past, different theories of treaty succession, reaching from the continuity doctrine to the clean-slate rule, were developed in conformity with the prevailing political circumstances, although presently the continuity doctrine prevails to a certain extent. Broadly speaking, different treatment can be expected depending on the type of State succession at issue: cession, merger and incorporation, dissolution and separation, as well as (the now largely historical) cases of emerging newly independent States.20

(p. 399) Unlike other areas of the law of treaties, State succession is not governed by the 1969 Vienna Convention on the Law of Treaties (VCLT).21 The relevant legal regulations must thus generally be found in customary international law. As Brigitte Stern has pointed out,22 most of this customary international law could be understood as merely the ‘translation’ of certain general principles of international law into the State succession context, such as the uti possidetis principle,23 the principle of effectiveness of territorial regimes,24 the fundamental principle of consent as expressed inter alia in Article 57 of the VCLT, and the principle relating to a fundamental change of circumstances (Article 62 of the VCLT). As a result of the ILC’s codification efforts, some of the relevant customary international law is mirrored in the VCSST. In contrast to the VCLT, however, the VCSST reflects the respective customary rules only to a limited extent. Moreover, as a treaty, the VCSST has not received widespread adherence,25 although it entered into force due to the limited number of ratifications required.26

The present state of affairs relating to treaty succession proves that the VCSST can serve as a reliable guide to the current State of customary international law only regarding some of its provisions (eg Article 11’s continuation of all boundary treaties, Article 15’s ‘moving treaty boundaries’ rule), while others constitute progressive development of international law (eg Article 31 in cases of incorporation; Article 34 in cases of separation). In any case, modern treaty succession distinguishes not only among the different cases of State succession, such as merger or dismemberment, but also among specific categories of treaties that are subject to different rules. Thus, it is difficult to identify a generally applicable legal regime of treaty succession. It still depends on the individual case and on the particular political context in which succession occurs.

(p. 400) I.  General Framework: Definitions, Theories, Effects, and Taxonomy of Treaty Succession

A.  Definitions

The VCSST’s definition of a ‘succession of States’ as laid out above27 is widely accepted.28 Although it only refers to cases of internationally lawful State succession,29 most cases of interest in this general overview may be subsumed under this definition due to its otherwise broad scope.30 Similarly, the VCSST provides a definition of ‘successor State’ as the State ‘which has replaced another State on the occurrence of a succession of States’.31 Accordingly, a successor State need not necessarily be a new State, but could comprise an old one acquiring new territory to which the regime of State succession applies.32 The law of treaty succession is also structured around a number of other concepts, including those of ‘treaty’ and ‘reservation’, which are defined in the VCSST in the same terms as in the VCLT.33 In contrast, a ‘newly independent state’ is defined in Article 2(1)(f) of the VCSST as a specific type of successor State, namely one ‘the territory of which immediately before the date of the succession of States was a dependent territory for the international relations of which the predecessor State was responsible’.

B.  The spectrum of opinions: from tabula rasa to universal succession

Over the years, different authors34 and international institutions, such as the International Law Association (ILA),35 have tried to come to grips with the legal problems ensuing from State succession. Historically, however, the applicable international law has remained rather vague, primarily because State practice itself has been and remains largely inconsistent. Different theories and approaches to treaty succession have become prominent depending on the respective political context as well as the changing attitude of States regarding the integration of new States into the existing community. As a result, a near permanent fluctuation (p. 401) between theories has occurred. For instance, Makonnen36 has distinguished: (i) the theory of universal succession first put forward by Grotius and later adopted by a number of jurists;37 (ii) the popular continuity theory (a variation of the universal succession theory taking regard of obligations of a ‘political character’);38 (iii) the organic substitution theory of continuity (as first advanced by Huber and constituting an adaptation of the universal succession theory);39 (iv) the clean-slate theory40 with its socialist aberration (the latter also considering radical changes in government as cases of State succession);41 (v) a theory of continuity of rights and obligations by virtue of the general principles of law, attributed to O’Connell;42 and (vi) moderate theories of continuity, which took an intermediate stance between the clean-slate theory and the universal succession theory.43 It can quite safely be argued that each of these theories was developed subject to a particular political context and ideology. Changes in context and ideology frequently prompted a change of theories.44

In general, the spectrum of legal conceptions and attitudes of States to treaty succession has ranged between two poles: the clean-slate rule (tabula rasa doctrine or negative theory), on the one hand, and the theory of continuity, on the other. The clean-slate rule holds that upon a change of sovereignty over territory the new sovereign is absolutely free of any of the obligations that bound its predecessor. This doctrine puts emphasis on a theory of complete and automatic discontinuity of all rights and obligations upon State succession.45 Its adherents emphasize State sovereignty as the reason a new State is not bound by the obligations of its predecessor. They also stress that succession in domestic law, where the successor assumes the rights and obligations of the predecessor, is different from succession in international law, where sovereign States are the main actors.46 Under the continuity theory, in contrast, all treaties existing at the date of succession continue to bind the successor State, which in some sense inherits all pre-existing treaties whether or not the predecessor State continues to exist.47

(p. 402) As discussed below, under customary international law and the VCSST, more sophisticated and more complex rules have developed than would follow from simply applying either the clean-slate principle or the continuity theory’s rule of universal succession. Nevertheless, the dichotomy of universal succession and clean slate sheds light on the varying concepts of international law underlying the respective approaches48 and serves to frame the variety of available solutions to the highly contextualized problems of State succession.

C.  International and domestic legal effects of treaty succession

The international legal effects of treaty succession may be understood as the establishment of new treaty relations different from those that existed between the other State party and the predecessor State. Those effects occur, moreover, irrespective of whether the predecessor State continues to exist or not. Although it may be disputed in some details—in particular with regard to the existence of a norm of general international law and its precise content—the view expressed by Kelsen seems thus still to be adequate: ‘[D]evolution of obligations and rights of one State on another does not imply identity of these obligations and rights; it means only that general international law imposes upon the successor State certain obligations and confers upon it certain rights which have the same content as certain obligations and rights of the predecessor’.49

In contrast to the attention devoted to the international legal effects of treaty succession, with the exception of O’Connell,50 the doctrine has remained rather silent as to the legal effect of treaty succession in domestic law. That, however, does not diminish the complexity of the issue. If treaty succession is understood as some sort of ‘novation’51 creating new treaty relations, the question remains how the legal effect of these new relations is produced within the domestic legal order. Unlike the conclusion of other new treaties by the relevant State, no parliamentary approval is required in order to establish new treaty relations via treaty succession. This raises several interesting, but as yet, unanswered questions. For example, can a rule of general international law on treaty succession, if it exists, replace the procedure required by the relevant national constitution to make a treaty applicable within that domestic legal system?52

(p. 403) D.  Taxonomy of State succession

The ILC, when elaborating what became the VCSST, did not consistently differentiate among legal effects according to the various cases of succession. But it is undeniable that certain differences exist, particularly in light of the latest practice.53 For instance, practice indicates that it is important to distinguish cases of State succession where the predecessor continues to exist from those where it ceases to exist, as in cases of dismemberment. Important cases of State succession broadly include the cession of part of a State forming a new State (eg generally the cases of newly independent States) or becoming part of another already existing State (eg the cases of Hong Kong, Macao, and Walvis Bay), the separation of parts of territory from a continuator State (eg the case of the former USSR), the complete breaking up of a State into different new ones (eg the case of the former SFRY), the uniting of two or more States into a new one (eg the case of Yemen), or the mere disappearance of a State, the territory of which is incorporated into another State (particularly the case of the GDR and the FRG).

Treaty succession operates differently in each of these cases and thus suggests the following taxonomy for devising an overview of the main customary rules: (1) newly independent States, (2) cession, (3) incorporation, (4) merger, (5) dissolution, and (6) separation. Additionally, annexation is discussed as a further category posing special problems due to its unlawful nature. At the same time, treaty succession does not correlate only with a particular category of State succession; it can also turn on the type of treaty at issue. Particular types of treaties, such as those relating to boundaries or those whose continued application would be incompatible with the object and purpose of the treaty concerned, are governed by special rules or are not affected by the legal regime of State succession at all.

1.  Newly independent States

The VCSST singles out for special treatment newly independent States, defined as successor States ‘the territory of which immediately before the date of the succession of States was a dependent territory for the international relations of which the predecessor State was responsible’.54 This category of States was based on the wave of new States emerging from the process of decolonization,55 a process that pushed (p. 404) the issue of State succession itself onto the ILC’s codification agenda.56 At the time, the ILC could gain very little from precedents outside this process. Many newly created developing countries rejected any idea of a continuity of treaty relations. In their view, the continuity theory was developed by certain industrialized countries under conditions foreign to the situation of these new developing States.57 These successors to the colonial powers wanted to become free of the treaties concluded by those powers. They invoked principles of State sovereignty, equality, self-determination, and permanent sovereignty over natural wealth and resources to justify this outcome. In terms of treaty succession, they favoured an optional theory where they could choose which treaties to continue; a position they repeatedly voiced during the ILC codification process.

In light of these claims and their historical context, it was no surprise that the ILC felt itself compelled to separate the regime on State succession into two distinct legal regimes, one based on the optional theory and covering ‘newly independent States’, and the other applying a modified continuity regime to all other cases of State succession. This distinction was then incorporated into the VCSST as well the Vienna Convention on Succession of States in Respect of State Property, Archives, and Debts of 1983.58 Thus, it was a distinction of great importance for cases of newly independent States, both before and shortly after the adoption of the VCSST. But as the process of decolonization came to an end, the newly independent States classification lost much of its relevance. By 1999, the category was no longer employed when the ILC submitted to the UN General Assembly draft articles on nationality of natural persons in relation to the succession of States.59

2.  Cession of territory

Cession of territory has resulted from changes of territory without the creation of a new State or the extinction of an old one. Cession was defined by Oppenheim as ‘the transfer of sovereignty over state territory by the owner-state to another state’.60 Cases of cession61 were seen in the 1867 cession of Alaska,62 the 1871 cession of Alsace and Lorraine by France to the German Empire, the Treaties of Versailles, St Germain and Trianon following the First World War, the Treaties following the Second World War relating to Germany, Italy, Romania, and Hungary, the 1962 (p. 405) cession of West New Guinea to Indonesia,63 the 1994 transfer of Walvis Bay from South Africa to Namibia64 as well as the retransfers of Hong Kong65 and Macao66 from the United Kingdom (UK) and Portugal to China in 1997 and 1999, respectively.

3.  Incorporation

The VCSST is silent on a situation of one or more States being incorporated into another and the latter ceasing to exist. However, the incorporation of the GDR, which became part of the FRG in 1990,67 provides a recent and important example of this situation. Previous cases of incorporation occurred with the United States’ 1845 accession of Texas,68 Italian unification in 1860, the 1866 expansion of Prussia,69 the 1871 creation of the German Empire,70 Britain’s 1886 incorporation of Burma,71 France’s 1885/96 incorporation of Madagascar,72 the United States’ 1898 incorporation of Hawaii,73 Belgium’s 1908 incorporation of independent Congo,74 the Kingdom of Yugoslavia’s incorporation of Montenegro,75 Malaysia’s 1963 incorporation of Singapore,76 and arguably, the unification of the two Vietnamese States in 1976.77

4.  Annexation of territory

Annexation, which may be understood as the ‘forcible acquisition of territory’ by a State,78 is to be kept separate from both cession and incorporation. Whereas in former centuries annexation was considered as lawful,79 presently, it is deemed to contradict basic rules of general international law, such as the principle of the non-use of force. Being wrongful, annexation poses particular problems due to the dependency of the applicability of the respective rules on treaty succession on the lawfulness of State succession.80

5.  Merger

Important cases of merger, where two or more States decide to form a new State, have been observed in the 1958 merger of Egypt and Syria to form the United Arab (p. 406) Republic (UAR),81 the 1964 merger of Tanganyika and Zanzibar to form Tanzania as well as the union, based on a 1990 merger, of the Yemen Arab Republic and the State of the People’s Democratic Republic of Yemen.82

6.  Separation

In cases of separation, one of the entities existing on the territory of the predecessor State separates and forms a new State, whereas the other part continues its legal personality and is, as such, identical with that predecessor State, although to a more limited geographical extent. Recent examples of separation include the separation of Eritrea from Ethiopia in 1993,83 and the USSR. In the latter case, the Russian Federation was generally considered to have continued the legal personality of the USSR as—in the Russian phraseology—a continuator (‘prodolžatel’), even if this result was initially controversial in doctrine.84 Following the dismemberment of former Yugoslavia, Montenegro (and Kosovo if it is recognized as a new State) separated from Serbia, which continued its legal personality.85

7.  Dissolution

Dissolution occurs when a part (or parts) of the territory of a State separate and form one or more new States with the predecessor State ceasing to exist. The most important recent cases of dissolution are provided by the dissolution of the former Yugoslavia (SFRY) as well as of Czechoslovakia (CSFR). An earlier case arose in the dissolution of the Republic of Great Colombia into Ecuador, New Grenada, and Venezuela.86

II.  The Substance of the Law of Treaty Succession

As pointed out above, the dichotomy between the clean-slate rule and the continuity theory have framed the debate about the law of treaty succession. At the same time, whatever the default rules of treaty succession may be in particular instances, the ability of successor States and third States to agree on their treaty relations must be kept in mind. Since at least the nineteenth century, the clean-slate (tabula rasa) rule87 was favoured by some and considered complementary to the principle (p. 407) of self-determination.88 Developing countries especially relied on this doctrine to resist treaties of the former colonial powers that were dictated upon them and in whose elaboration they did not take part. The ILC later accepted it for the category of newly independent States, even if the practice before 1978 was not entirely conclusive in this regard.

On the other hand, the continuity theory is supported by the fact that the rules of general customary international law are likewise binding upon new States, including newly independent States, despite their inability to participate in their formation. As a result, the denial of the continued application of at least certain general multilateral treaties is difficult to justify. Moreover, irrespective of the special case of newly independent States, other political considerations speak against a general application of the clean-slate doctrine and in favour of a presumption of treaty continuity. Modern States are embedded in an intensive set of commonly shared values and interests governing their social life, all of which are the product of very dense treaty relations. The density of these treaty relations rules out any clear-cut clean-slate concept. State social life, which is to a significant extent and increasingly also cross-border, undoubtedly relies on continuity. A breakdown of these relations in the case of a change of Statehood would severely damage the stability of international society. In addition, international society can no longer be—if it ever could have been—conceived as a society merely of States, but also includes non-governmental actors, in particular individuals. This circumstance is visible in nearly all parts of the world, but especially in Europe, where transnational instead of intergovernmental transboundary cooperation is the rule.89 A termination of treaties carving the legal frame and foundation for those transnational contacts and cooperation would simultaneously and necessarily entail an end to such transnational policy. Only when the new social situation created by a political transformation involving State succession changes radically, would a termination of treaty relations seem an appropriate solution. State practice seems to have sensed this need. Hence, the clean-slate rule has not reflected the state of affairs of existing international relations, particularly in relation to States belonging to the same geographical region or those purporting to share the same basic values.90

But despite these considerations in favour of the continuity doctrine, and their applicability to the latest wave of State succession cases, no settled State practice supports the exclusive general validity of this doctrine. The only conclusion which can safely be drawn is that a universally applicable rule of international law for (p. 408) treaty succession does not yet exist, neither one based on the clean-slate rule nor on that of continuity91 (although a certain tendency towards the continuity theory cannot be denied). Rather, different rules and practices have emerged for the categories of State succession outlined above and with respect to particular kinds of treaties.

A.  Unilateral declarations and devolution agreements

Before assessing the specific categories of State succession and rules for particular types of treaties, a preliminary word is necessary on the practice of unilateral declarations and devolution agreements. As a general matter, the legal effects of treaty succession result from the application of a generally applicable rule of international law, either derived from customary international law or treaty law (eg the VCSST for those States party to it). Moreover, in almost all cases there can be a specific rule agreed upon by the relevant States, ie the new State and the State which is the other party to the relevant treaty.

A new State may also conclude a devolution agreement with the predecessor State or issue a unilateral declaration on treaty succession.92 Both of these instruments purport to indicate those treaties to which the new State has (or has not) succeeded. As the VCSST confirms, however, neither a unilateral declaration by the successor State (Article 9 of the VCSST) nor a devolution agreement between the predecessor and successor State (Article 8 of the VCSST) can of itself exercise any legal effect on another State party. The other party to the treaty must usually acquiesce or explicitly express its consent thereto pursuant to the notion that a treaty cannot create rights or obligations for a third party without its consent (the pacta tertiis rule).93 A declaration of succession has no legal effect with respect to State succession in treaties, other than as a notification of succession by a newly independent State pursuant to Articles 17 and 18 of the VCSST. In this respect, Article 9(1) of the VCSST undoubtedly reflects customary international law when it provides that a State does not succeed in treaties ‘by reason only of the fact that the successor State has made a unilateral declaration providing for the continuance in force of the treaties in respect of its territory’. This understanding is confirmed by the practice of the UN Secretary-General according to which general declarations of succession do not suffice to establish the State’s status as a party to a multilateral treaty.94 Thus, the Secretary-General’s practice is to duly comply with a new State’s request to circulate its ‘general’ declaration of succession to all UN members, but not to ‘consider such a declaration as a valid instrument of succession to any of the treaties deposited with him’ and to inform the new State thereof.95

(p. 409) Despite the lack of legal effect for third States,96 devolution agreements remain significant in practice. They can oblige the successor State in relation to the predecessor State in two ways, either by (a) declaring accession or succession in respect of certain treaties covered by the devolution agreement,97 or, (b) in the case of automatic succession under customary international law, not denying such automatic succession.98 As to multilateral treaties, it has been the practice of depositaries, particularly the UN Secretary-General, to request a successor State to specially confirm the succession expressed in its respective devolution agreement.99 In general, devolution agreements enunciate the attitude of the relevant successor State100 and thus further predictability and stability in the context of an area of law otherwise tending towards uncertainty.

B.  Newly independent States

Part III (Articles 16–30) of the VCSST prescribes specific rules for treaty succession involving newly independent States. Article 16 adopts the clean-slate rule as a general rule for these States. Article 17 provides an additional right of optional succession to newly independent States, allowing them to establish their status as parties to any multilateral treaty by a notification of succession, unless it is otherwise established that it would be incompatible with the treaty’s object and purpose or would radically change the conditions of the treaty’s operation. Article 27 also allows a newly independent State to provisionally apply a multilateral treaty by notification with any other party that expressly agrees to such provisional application or by reason of its conduct can be considered to have so agreed.101

The practice was inconsistent at the time of the VCSST’s adoption. After 1978, however, newly independent States by and large followed the model prescribed by the VCSST.102 The VCSST provisions, namely Articles 17 and 27, applied a modified version of the clean-slate doctrine known as Nyerere formula.103 According to the eponym of this formula, Julius Nyerere, the first president of Tanzania, international agreements dating from colonial times should be renegotiated when a State becomes independent, since the nation should not be bound by a treaty that it was not in a sovereign position to conclude at that time. Accordingly, such a State should be entitled—upon its independence—to review the international treaties of its colonial power and decide which of the agreements it would accept and which repudiate. Such an ‘optional’ approach to events of State succession was certainly (p. 410) not new; however, it can hardly be stated that it was already recognized by customary international law.

In contrast to the pure tabula rasa (clean-slate) doctrine, the Nyerere doctrine differs to the extent that under the former a new State emerges without any of the obligations of the predecessor State whereas, under the latter doctrine, this is only an assumption. The Nyerere doctrine does not rule out or prejudice the possibility or desirability of renewal (after a legal interruption during the succession) of commitments or agreements of mutual interest to the parties concerned. It does, however, reject any categorization of international obligations between those which the successor State would have to accept and those which it could reconsider. Nyerere also created a formula for the practical application of this doctrine, which provides for an interim reflection period during which some of the predecessor’s treaties apply provisionally while the successor chooses which treaties it will renew or renegotiate and which it will set aside.104 Both the doctrine and the formula, with case specific variations, served as a framework for State succession among East African States as well as for many other developing countries. In most instances, predecessor States and third States have accepted—if not indeed supported—the application of the Nyerere doctrine. Thus, while at the time of its elaboration the practice of newly independent States was not entirely consistent, the practice of States after 1978 shows that the provisions of Part III of the VCSST have largely been followed. In particular, States followed the practice of provisional application enshrined in Article 27 of the VCSST in respect of multilateral treaties, in line with the Nyerere formula. With the end of the process of decolonization, however, these rules for newly independent States have ceased to be particularly pertinent in modern practice.

C.  Succession of States other than newly independent States

1.  Cession of territory

Article 15 of the VCSST prescribes the so-called ‘moving treaty boundaries’ rule to cases of cession of territory.105 According to this rule, when part of the territory of (p. 411) one State becomes part of the territory of another State, treaties of the former cease to apply to the territory while the treaties of the latter extend to the territory. Both State practice before 1978 as well as thereafter has confirmed the validity of this rule as part of customary international law.106 For example, the retransfer of Hong Kong by the UK to China was subject to particular agreements,107 which per se do not have third party effect, but were largely guided by the ‘moving treaty boundaries’ rule.

2.  Incorporation

The VCSST did not anticipate or accommodate the important recent case of the former German Democratic Republic (GDR) that was incorporated into the Federal Republic of Germany (FRG). Neither Article 31 of the VCSST relating to the ‘effects of a uniting of States in respect of treaties in force at the date of the succession of States’108 nor Article 15 relating to the ‘succession in respect of part of territory’ covered the complete incorporation of one State by another, existing State.

Without embarking on the Berlin question or the FRG and GDR’s legal status after the Second World War, it suffices to proceed from the undisputed fact that the GDR enjoyed the status of a State as a separate subject of international law. It was recognized by the community of States irrespective of the particular view of the FRG, and was, like the FRG, a UN member and a State party to numerous bilateral and multilateral treaties. But, by 3 October 1990, the GDR ceased to exist as a separate State and became part of the FRG. This unification did not result in a new State; the FRG remained identical with the FRG before unification, albeit enlarged in terms of territory and population. Still on the eve of this event, both States agreed among themselves on the regulation of questions relating to treaties concluded by them. Article 11 of the Unification Treaty109 provided for the automatic extension of treaties concluded by the FRG to the entire territory of the State, in application of the principle of ‘moving treaty boundaries’, except for certain explicitly mentioned treaties deemed of a ‘highly political’ nature. As to the GDR’s treaties, according to Article 12 of the Unification Treaty, these were to become the subject of negotiations between Germany and the relevant other State Party, taking into account various factors, including the need for protection of confidence, the (p. 412) interests of the States concerned, the FRG’s treaty obligations, the competence of the EC, as well as the principles of a free, democratic basic order governed by the rule of law.110 It was further envisaged that Germany would define its final stance concerning those treaties only after consultations with the other parties to the treaty concerned.111

For future situations of incorporation, the case of the former GDR112 indicates that the rule of Article 31 of the VCSST is not a reliable guide to customary law. In contrast, the principle of the ‘moving treaty boundaries’ rule generally remains applicable, ie the treaties of the incorporated State cease to apply while the remaining State’s treaties remain in force and extend to the enlarged territory.113

3.  Merger

In contrast to incorporation, the case of Yemenite unification and other instances of a union of States with the predecessor States ceasing to exist, point to Article 31 of the VCSST expressing an emerging customary rule for merger.114 In this context, the VCSST enshrines a territorially limited continuity approach. In particular, Article 31(1) provides that ‘[w]hen two or more States unite and so form one successor State, any treaty in force at the date of the succession of States in respect of any of them continues in force in respect of the successor State’ unless the States otherwise agree or ‘it appears from the treaty or is otherwise established that the application of the treaty in respect of the successor State would be incompatible with the object and purpose of the treaty or would radically change the conditions for its operation’. Article 31(2) provides that any treaty continuing in force under Article 31(1) ‘shall apply only in respect of the part of the territory of the successor State in respect of which the treaty was in force at the date of the succession of States’ unless, in the case of a multilateral treaty not of the category mentioned in Article 17(3),115 ‘the successor State makes a notification that the treaty shall apply in respect of its entire territory’ or, in all cases, unless ‘the successor State and the other States Parties otherwise agree’.

The unified Republic of Yemen was created pursuant to a 1990 agreement between North and South Yemen.116 A corresponding joint letter addressed to (p. 413) the UN Secretary-General accepted Article 31’s direction that the treaties of both States should continue, declaring that ‘all treaties and agreements concluded between either the Yemen Arab Republic or the People’s Democratic Republic of Yemen and other States and international organizations in accordance with international law which are in force on 22 May 1990 will remain in effect’.117

4.  Separation

Article 34 is one of the core VCSST provisions, adopting a continuity theory for separating States other than newly independent States. It provides that ‘any treaty in force at the date of the succession of States in respect of the entire territory of the predecessor State continues in force in respect of each successor State so formed’. Any treaty that applied only to that part of the territory of the predecessor State, which has become a successor State, is likewise to continue in force in respect of the latter only. With regard to a remaining predecessor State, Article 35 of the VCSST provides that existing treaties remain in force after the succession in respect of the remaining territory, likewise subject to special agreement by the States concerned and the nature of the treaty in question. The ILC itself acknowledged in its commentary on draft Articles 32 to 34, which became Articles 33 to 35 of the VCSST, that State practice contained certain inconsistencies.118 Nevertheless, the ILC found the practice sufficiently consistent to support their formulation of these draft articles.

In reality, however, inconsistencies in the practice before and after the VCSST’s adoption cast doubts as to whether the continuity rule expressed in Article 34 of the VCSST applies to all cases of separation.119 Generally, the most recent practice of successor States in cases of separation has been less uniform than in the recent cases of dissolution.120 That practice does nevertheless offer support for Article 34’s limitations on the continued legal force of treaties insofar as the States concerned (the parties to the relevant treaty) could otherwise agree or continuity as reflected in Article 34(1) of the VCSST would not apply if ‘it appears from the treaty or is otherwise established that the application of the treaty in respect of the successor State would be incompatible with the object and purpose of the treaty or would radically change the conditions for its operation’. With regard to bilateral treaties, this limit is usually reflected in the practice of States through an agreement on a list of treaties that are considered to be still applicable. This list is deemed to be declaratory only;121 it is normally not submitted to parliamentary approval or (p. 414) other domestic constitutional procedures generally required for the conclusion of treaties.122 Practice also shows that, in the case of multilateral treaties, succession has generally been deemed admissible with ex tunc effect upon a notification of succession.123 In the case of bilateral treaties, however, succession was made subject to individual appraisals by the parties, although generally a tendency towards continuity has been maintained.124

The most important recent case of separation concerned the former republics of the USSR. Geopolitical changes on the territory of the former USSR commenced with the demand of the Baltic Republics (Lithuania, Latvia, and Estonia) for their independence as sovereign States in 1989, a status which they had already enjoyed prior to the Second World War.125 Lithuania declared its independence restored as early as 11 March 1990.126 But it was only on 6 September 1991 after various events127 and decrees128 calling on the community of States to recognize their independence129 that these States obtained recognition as independent States by the Soviet Union still existing at that moment.130 The Baltic States did not, however, consider themselves to be new States but identical with those existing prior to the Second World War and occupied since then by the USSR. As a result, they declined any succession in treaties entered into by the USSR.131

Following the Baltic States, the other Union Republics132 also called for independence.133 Ukraine, Belarus, and Russia formally declared the disintegration of the USSR on 8 December 1991. Signatories of the Agreement of Minsk of 8 December 1991 (Belarus, Russian Soviet Federative Socialist Republic (RSFSR), (p. 415) and Ukraine) committed themselves ‘to discharge the international obligations incumbent on them under treaties and agreements entered into by the former Union of Soviet Socialist Republics’.134 With the exception of Georgia and the Baltic States, all former Union Republics of the Soviet Union established the Community of Independent States (CIS) with the Declaration of Alma Ata of 21 December 1991. The Alma Ata Declaration also indicated that the USSR had begun the process of ending its existence upon the establishment of this Commonwealth.135 Through a 21 December 1991 Protocol to the Minsk Agreement, other States forming the CIS joined the commitment under the Minsk Agreement.136

As far as their legal status is concerned, the States presently existing on the territory of the former USSR cannot be treated in an equal manner. As to the Baltic States, despite singular views to the contrary,137 the opinion prevails that they re-established the Statehood they possessed before 1940138 and, therefore, did not fall under the regime of State succession. Ukraine139 and Belarus also operated as special cases since they were already members of the UN and parties to several international multilateral and bilateral treaties and had enjoyed a certain restricted international legal personality prior to their full independence and Statehood in 1991.140

The Russian Federation raised difficult problems by claiming an identity with the former USSR irrespective of the Declaration of Alma Ata. This posed the question of whether events had produced either a dismemberment of the former USSR or a separation of certain parts of the territory of the USSR combined with a redesignation of the USSR as the Russian Federation. Under the latter view, the Russian Federation would remain party to all treaties that the USSR had entered into.141 The Russian Federation officially adopted this view,142 declaring itself as the ‘continuator’ and not a successor to the USSR. Even though the continuator concept was relatively novel at the time, the Russian Federation’s view was generally accepted by other States143 as well as by the UN where the name ‘Union of Soviet Socialist Republics’ was only replaced by the new name ‘Russian Federation’.

As to the remaining States emerging from the USSR, they undoubtedly became new States subject to the regime of State succession. Although the Baltic States144(p. 416) and certain other States145 contended they were newly independent states, they were not entitled to that qualification. Unlike colonies, these entities enjoyed the same legal status as all other Union Republics in the framework of the Soviet Union and were equally represented in the National Council as part of the Supreme Soviet.146 Thus, irrespective of the concentration of actual political decision-making power in small elite bodies outside the formal government (namely the communist party),147 these States can hardly be equated with the former colonies148 according to the UN terminology.149 As a result, they could not claim the status of newly independent States, and consequently, State practice since then has generally rejected their qualification as such.

5.  Dissolution

In contrast to cases of separation where the prior practice was inconsistent, at the time of its adoption, Article 34 of the VCSST did codify the customary international law applicable to cases of dissolution.150 Moreover, subsequent practice has generally, if not exactly, confirmed this rule, particularly in the cases of the former SFRY and the former CSFR. These two cases of dissolution displayed more consistency in the continued application of multilateral treaties than the USSR’s separation. Nevertheless, in the case of multilateral treaties, the practice of the UN Secretary-General additionally requires a declaratory notification of succession by the States concerned.151 In the case of bilateral treaties, negotiations tend to be the rule, leading to exchanges of notes including non-constitutive lists of treaties to remain in force, similar to cases of separation.152

The geopolitical changes relating to the SFRY153 were connected with much more bloodshed, atrocities, and cruelties than the other cases mentioned here.154 The dissolution started with the proclamation of independence of Slovenia and Croatia on 29 June 1991. Following the delivery of Opinion No 7 of the EC Arbitration Commission,155 the EU recognized Slovenia as an independent State (p. 417) on 15 January 1992,156 simultaneously with its recognition of Croatia. Both States became new members of the UN on 22 May 1992 and were accepted, although differently, by the community of States.157

Doubts were initially raised as to the ability of Bosnia and Herzegovina to effectively govern its territory.158 Nevertheless, after it declared independence in November 1991, EU member States and the US recognized it as a State on 7 April 1992, and it was admitted to the UN as a new member on 22 May 1992.159 As to Macedonia or, in UN terminology, Former Yugoslav Republic of Macedonia (FYROM), the question of its recognition was overshadowed by the dispute over its name. Once it was admitted to the UN on 8 April 1993,160 it was also accepted by the community of States as an independent State161 and recognized by a great number of States.

The remaining part of the former SFRY, formerly forming the Republics of Serbia and Montenegro and comprising about 40 per cent of the area and 44 per cent of the population of the SFRY,162 claimed identity with the SFRY from a legal point of view.163 However, other States did not accept this claim. The Opinion of the EC Arbitration Commission164 as well as resolutions of the UN Security Council165 and the General Assembly required the Federal Republic of Yugoslavia (Serbia and Montenegro) to apply for new membership in the Council of Europe and the UN, respectively.166 The only conclusion that can be drawn from this is that this State is a new one, succeeding to the former SFRY like all the other new States formed in this region.167 That view was confirmed by EU member States’ recognition of this State in April 1996 and by its admission to the UN as a new State in 2000.168 Hence, the former SFRY has to be considered as dismembered and that so far, six (and, if Kosovo is regarded as a new State, seven) new States have emerged on its territory.169

Notwithstanding the fact that unilateral declarations cannot produce any legal effect for other States,170 Slovenia included in one of its first constitutional acts a (p. 418) provision according to which the ‘[i]nternational agreements concluded by Yugoslavia and relating to the Republic of Slovenia shall be effective in the territory of the Republic of Slovenia’.171 In the framework of the Meeting of the Legal Advisers within the Council of Europe, the representative of Croatia stated that ‘his country would respect all the treaties of former Yugoslavia (unless they conflicted with the constitution)’.172 No such acts were produced by the other parts of former Yugoslavia.173

The other, though peaceful, recent case of dismemberment arose with the emergence of the Czech and Slovak Republics. The first change affecting Czechoslovakia after the Velvet Revolution altered that State’s name from CSSR to CSFR, but this did not affect its legal personality under international law. However, on 25 November 1992, the Federal Assembly of the CSFR adopted legislation providing that as of midnight, 1 January 1993, the State of Czechoslovakia would cease to exist and would be succeeded by two independent new States, the Czech Republic and the Republic of Slovakia (Slovak Republic). By the same date, both new States were recognized by the member States of the EU and the US.174 Thus, these events amounted to a classic case of dismemberment of one State succeeded by two new States.

Like Slovenia and Croatia, the Parliaments of both component parts of the CSFR adopted on 2 December 1992175 and 17 December 1992176 a Declaration according to which, as of 1 January 1993, they declared themselves bound by multilateral and bilateral treaties and agreements to which the CSFR was a party by that date. The constitutional law of the Czech Republic No 4/1993 stipulates that the ‘Czech Republic takes over rights and obligations … deriving for Czechoslovakia on the date of its extinction from the international law, except those … relating to the territory which was under (Czechoslovakia’s) sovereignty but is not under the sovereignty of the Czech Republic’.177 According to Article 153 of the Constitution of the Slovak Republic, this State succeeded to all rights and duties ensuing from international treaties and agreements binding former Czechoslovakia.178

(p. 419) In sum, with certain modifications, as indicated above, the continuity principle as laid down in Article 34 of the VCSST forms the vantage point for treaty succession in cases of dissolution, frequently accompanied by declaratory notifications of succession in the case of multilateral treaties, and frequently modified by agreement between the parties in accordance with the varying context of each case of succession, especially in the case of bilateral treaties.

D.  Legal regimes not affected by State succession

Even where customary legal rules exist for particular categories of treaty succession, those rules will not govern all treaties. Some treaties create legal regimes that are not affected by State succession.

1.  Boundary treaties

The law and practice of State succession to boundary treaties is based on the acknowledgment of the particular nature of boundary treaties. As expressed by the ICJ in the Temple of Preah Vihear case, the primary object of a boundary treaty is to ‘achieve stability and finality’.179 Article 11(1) of the VCSST provides that a ‘succession of States does not as such affect … a boundary established by a treaty or … obligations and rights established by a treaty and relating to the regime of a boundary’. The ILC’s First Report on Succession of States and Governments in Respect of Treaties in 1968 found that:

the weight both of opinion and practice seems clearly to be in favour of the view that boundaries established by treaties remain untouched by the mere fact of a succession. The opinion of jurists seems, indeed, to be unanimous on the point … [and] State practice in favour of the continuance in force of boundaries established by treaty appears to be such as to justify the conclusion that a general rule of international law exists to that effect.180

Subsequent practice also confirms that this rule may be considered as customary both with regard to land181 and to maritime boundaries.182 This rule enhances the stability of boundaries and is in conformity with the principle of the intangibility of frontiers as reflected in the generally applicable principle of uti possidetis.183

2.  Other territorial regimes

Besides the special case of boundary regimes, another traditional distinction was generally made between personal and dispositive treaties. According to one author, (p. 420) personal treaties are contractual in nature and, therefore, depend on the continued existence of the parties; dispositive treaties, by contrast, create rights in the land and survive all changes in sovereignty.184 Accordingly, a dispositive treaty has a legal effect similar to a covenant running with land—the territory gains permanent status independent of the personality of the State exercising sovereignty.

According to Article 12 of the VCSST, dispositive treaties, which it terms ‘other territorial regimes’, are not affected by State succession. Examples include treaties of cession, peace treaties, and treaties that grant ‘rights of way over territory’.185 As the ILC pointed out, the ‘weight of the opinion amongst modern writers supports the traditional doctrine that treaties of a territorial character constitute a special category and are not affected by a succession of States’.186 Although this ‘other territorial regimes’ category lacks a precise definition, the ILC’s first candidates (beside boundary regimes mentioned above) were treaties ‘concerning water rights or navigation on rivers’; other candidates included treaties for the neutralization or demilitarization of a particular territory, treaties according freedom of navigation on international waterways or rivers, and treaties for the equitable use of water resources in an international river basin.187 More generally, according to the ILC, this category is ‘limited to cases where a State by a treaty grants a right to use territory, or to restrict its own use of territory, which is intended to attach to territory of a foreign State or, alternatively, to be for the benefit of a group of States or of all States generally’.188 In the Gabčíkovo-Nagymaros case, the ICJ explicitly confirmed the customary nature of Article 12 of the VCSST.189 That case found that the territorial regime on the Danube established by the 1977 Treaty between Hungary and the CSSR had ‘establish[ed] a territorial régime within the meaning of Article 12’ of the VCSST since it created rights and obligations ‘attaching to the parts of the Danube to which it relates’ and therefore the treaty ‘itself cannot be affected by a succession of States’.190

3.  Permanent sovereignty over natural resources

The principle of permanent sovereignty over natural resources, which was derived mostly by developing countries from the principle of self-determination, was a point of contention during the elaboration of the VCSST, particularly due to the principle’s connection with the concept of acquired rights.191 Finally, Article 13 of (p. 421) the VCSST was elaborated and provided that nothing in the convention ‘shall affect the principles of international law affirming the permanent sovereignty of every people and every State over its natural wealth and resources’. The exact extent of the principle of permanent sovereignty over natural resources was—and remains—subject to debate even if it has been generally recognized as a principle of international law,192 and has been emphasized in Article 1 of both the International Covenant on Economic, Social and Cultural Rights and the International Covenant on Civil and Political Rights, both of 1966.193 In any case, since the wave of decolonization has passed, this principle has become less relevant in the context of the law of State succession.

4.  Other special categories of treaties

The legal effects of State succession may also depend on the nature and content of the relevant treaty in other respects. In particular, issues of succession may arise based on the treaty’s subject matter or the nature of the treaty commitment. In some cases, moreover, the rules for these other special categories remain contested or vague, and are thus still emerging.

(i)  Human rights and humanitarian law treaties

Times of fundamental change are particularly conducive to occurrences of State succession. In such instances, the guarantees accorded to individuals through various human rights and humanitarian law treaties may be especially relevant—particularly due to the specificity of treaty rules and the existence of compliance mechanisms that are lacking in the case of customary rules. Thus, the breakup of the SFRY was accompanied by numerous violations of international human rights and humanitarian law in the period between the independence of the successor States and their formal notification of succession. In view of such cases, proponents of succession have argued that the nature of human rights and humanitarian treaties should be described as similarly ‘attaching’ to individuals as territorial treaties attach to land.194

The VCSST is silent on the particular fate of human rights or humanitarian treaties in cases of State succession.195 Today, it remains unclear whether customary international law includes a rule of automatic succession to multilateral humanitarian and human rights treaties.196 The practice of the Czech and Slovak (p. 422) Republics with regard to the ECHR provides some degree of support for such a rule, albeit in a regional context.197 Moreover, the ICTY198 and to a certain extent the Eritrea-Ethiopia Claims Tribunal199 have pronounced themselves in favour of automatic succession in the case of certain universal human rights and humanitarian treaties. But, the ICJ has remained silent on the issue.

Most recently, in its judgment regarding preliminary objections in the Croatia-Serbian Genocide case, the ICJ found that the FRY succeeded to the Genocide Convention, without elaborating specifically how this succession occurred.200 Rather, the ICJ took account of the text of the FRY’s declaration and Note of 27 April 1992 on succession, alongside the consistent conduct of the FRY then and thereafter to find ‘that from that date onwards the FRY would be bound by the obligations of a party in respect of all the multilateral conventions to which the SFRY had been a party at the time of its dissolution, subject of course to any reservations lawfully made by the SFRY limiting its obligations’. Since the Genocide Convention had been one of these conventions, the ICJ held that the FRY in 1992 had accepted the obligations of that Convention.201 However, it did not pronounce itself on how this occurred, whether by way of automatic succession or via Article 34’s codification of a customary rule of international law.

In contrast, the Appeals Chamber of the ICTY held in the Čelebići case that:

irrespective of any findings as to formal succession, Bosnia and Herzegovina would in any event have succeeded to the Geneva Conventions under customary law, as this type of convention entails automatic succession, ie, without the need for any formal confirmation of adherence by the successor State. It may be now considered in international law that there is automatic State succession to multilateral humanitarian treaties in the broad sense, ie, treaties of universal character which express fundamental human rights.202

The Appeals Chamber found that:

the Geneva Conventions f[ell] within this category of universal multilateral treaties which reflect rules accepted and recognised by the international community as a whole. The Geneva Conventions enjoy nearly universal participation … In light of the object and purpose of the Geneva Conventions, which is to guarantee the protection of certain fundamental values common to mankind in times of armed conflict, and of the customary nature of their provisions, the Appeals Chamber is in no doubt that State (p. 423) succession has no impact on obligations arising out from these fundamental humanitarian conventions.203

Similarly, in the Partial Award relating to Prisoners of War, the Eritrea Ethiopia Claims Commission found that ‘[t]reaty succession may happen automatically for certain types of treaties’.204 However, in the instance at hand, the Commission found that it had ‘not been shown evidence that would permit it to find that such automatic succession to the Geneva Conventions occurred in the exceptional circumstances here, desirable though such succession would be as a general matter’205 since ‘[f]rom the time of its independence from Ethiopia in 1993, senior Eritrean officials made clear that Eritrea did not consider itself bound by the Geneva Conventions’.206 Moreover, this evidence was complemented by the fact that ‘[d]uring the period of the armed conflict and prior to these proceedings, Ethiopia likewise consistently maintained that Eritrea was not a party to the Geneva Conventions’207 and the ‘ICRC, which has a special interest and responsibility for promoting compliance with the Geneva Conventions, likewise did not at that time regard Eritrea as a party to the Conventions’.208

These divergent views correspond to a broader analysis of the practice relating to the Genocide Convention209 undertaken by Gaeta, who concluded that ‘it is unclear whether the succession to the Convention is automatic, or voluntary for a new State, though the latter view has more support’.210 However, it seems clear that for the purposes of international litigation ‘the consent of new states is required … whether they have as a substantive matter succeeded to the responsibility of their predecessor state or not’.211

(ii)  ‘Political’ treaties

Another category of treaties subject to particular rules lacks any clear definition; those treaties the application of which to the successor State would be incompatible with the object and purpose of the treaty or would radically change the conditions for its operation.212 This characterization—used repeatedly in the VCSST—is borrowed from the VCLT and tends to address those treaties which are also sometimes called ‘political treaties’.213 Some authors try to define this category in a negative manner by arguing that only those treaties should pass on to the successor States from which both Parties to the treaty benefit.214 But whatever efforts previously undertaken to define these categories of treaties, the definition (p. 424) still remains vague. In this respect, these treaties share the lack of a precise definition of the ‘object and purpose’.215 In practice, however, States have overcome the difficulty related to the vagueness of this phrase by drawing up a list of the agreements that were to remain in force.216

(iii)  Multilateral treaties

As far as multilateral treaties are concerned, the question arises as to whether the clause determining the conditions for becoming a party to the treaty also applies to the successor State or States. Both the VCSST217 as well as UN practice recognize that the conditions governing the right to become party to a specific treaty define also the category of States which may succeed to this treaty. Thus, the UN Secretary General’s Summary of Practice states that ‘[i]n the absence of provisions which set specific conditions for succession or which otherwise restrict succession; the Secretary-General is guided by the participation clauses of the treaties as well as by the general principles governing the participation of States’.218 This practice even acknowledges the possibility that treaty succession may be excluded.219

(iv)  Constitutive treaties of international organizations (IOs)

The regulation of the succession to constitutive treaties of IOs is widely subject to the special internal rules of the respective organizations. Generally, these rules do not allow for succession, but rather require accession to the organization’s constitutive instrument(s).220 Both in the practice prior and subsequent to the VCSST’s adoption,221 succession of new States to the constitutive instruments of IOs has generally not been accepted in cases of cession, dissolution, or separation. In cases of merger or incorporation, however, the practice has been for the incorporating State or the unified State to continue, or ‘substitute’, the IO membership, even if only following a notification of succession.222 Article 4 of the VCSST also anticipates special internal rules of IOs that would in some cases and under specific (p. 425) circumstances provide for succession; these are found especially among international and regional financial organizations, such as the World Bank, the International Monetary Fund, and regional development banks.223

(v)  Disarmament and arms control treaties

Agreements relating to military matters engender particular problems. In this regard, succession issues have been addressed differently in the case of generalized commitments not to possess or use certain weapons, on the one hand, and specific agreements about the number of weapons, on the other.224 The former could be seen as resembling other treaties codifying customary international law while the latter would lead to further issues concerning the legal status of the respective treaty commitments. Moreover, recent practice suggests that the regulation of both disarmament and arms control treaties largely depends on the intention of the parties. As a result, the specific context of each particular treaty is relevant and no general rule can be discerned, even if the need for stability and predictability supports a general notion of continuity (or at least the obligation to negotiate in good faith towards a regulation of disarmament and arms control).225

III.  Other Aspects of the Law of Treaty Succession

Article 20 of the VCSST only deals with reservations in the context of newly independent States and is therefore of considerably restricted use today.226 Recent practice shows that States may only retain reservations of the predecessor State but not formulate new ones with respect to treaties to which they are succeeding.227 Special problems may arise in the case of merger where reservations of the predecessor States conflict.228 The ILC, as part of its work on the topic of ‘the law and practice relating to reservations to treaties’, has dealt with the status of reservations, acceptances of, and objections to reservations, and interpretative declarations in the case of succession of States.229 In this context, the ILC maintains the specific (p. 426) category of newly independent States230 irrespective of the emerging tendency of renouncing such a category of States.

Articles 36 and 37 of the VCSST deal with questions of treaty succession with respect to the status of a predecessor State as contracting and signatory State, respectively. Article 36 of the VCSST provides that in cases of separation or dissolution, a successor State may, ‘by making a notification, establish its status as a contracting State to a multilateral treaty which is not in force if, at the date of the succession of States, the predecessor State was a contracting State to the treaty in respect of the territory to which the succession of States relates’. This provision has largely been confirmed by recent State practice.231 Article 37 of the VCSST provides an analogous provision for cases where, before the date of the succession of States, the predecessor State had signed a multilateral treaty subject to ratification, acceptance, or approval. While this rule did not constitute customary international law before 1978, it has since been largely confirmed by recent State practice.232

Another issue relevant for determining the effects of the applicable rules on treaty succession is the determination of the date of succession. Particularly in cases where State succession is the consequence of a protracted process or it is uncertain whether the new entity is a State, it can be difficult to ascertain the exact date when State succession occurs.233 Thus, one may contrast, for example, the protracted dissolution of the SFRY in the context of conflict or the case of some successor States of the USSR with several cases of decolonization or, more recently, the case of South Sudan’s emergence as a new State on a specific date.234


With the disappearance of the circumstances of decolonization, States have moved further away from the clean-slate doctrine, which, together with the continuity theory, has traditionally framed the law of treaty succession. Even if the principle of continuity in cases of treaty succession can be said to form a starting point of the law today, negotiations among States often modify this general precept. Likewise, different rules and practices have emerged for various categories of State succession and with respect to particular kinds of treaties. Any generalization thus fails to accord with the contextual nature of the law of treaty succession. At the same time, especially the moving boundaries rule for cases of cession and incorporation enjoys wide support in State practice. Similarly, constitutive treaties of IOs are generally not considered as permitting succession, but rather require accession. There is also (p. 427) legal certainty regarding the rule that certain boundary and territorial regimes are not affected by State succession. At the same time, while oriented towards continuity, particularly in the case of bilateral treaties, negotiation plays an important role in State practice in cases of dissolution and separation, albeit to different extents in each case.

Thus, the law of State succession with regard to treaties illustrates a still existing divergence of views and practice, although certain generally accepted tendencies are already recognizable. These tendencies point in the direction of a continuity of treaties, at least in respect of certain types of treaties such as those on human rights, which is obviously in the interest of the individuals and with the purpose of protecting their rights even if a State succession has occurred.

Recommended Reading

  • KG Bühler, State Succession and Membership in International Organizations: Legal Theories versus Political Pragmatism (Kluwer, London 2001)
  • M Craven, The Decolonization of International Law: State Succession and the Law of Treaties (OUP, Oxford 2007)
  • PM Eisenmann and M Koskenniemi (eds), La Succession d’Etats: La Codification à l’Épreuve des Faits/State Succession Tested against the Facts (Martinus Nijhoff, London 2000)
  • U Fastenrath, T Schweisfurth, and C Thomas, Das Recht der Staatensukzession (Müller, Heidelberg 1996) 49
  • ILA Committee on Aspects of the Law of State Succession, Draft Conference Report Rio de Janeiro Conference (2008)
  • J Klabbers, M Koskenniemi, O Ribbelink, and A Zimmermann (eds), State Practice Regarding State Succession and Issues of Recognition: The Pilot Project of the Council of Europe (Kluwer, London 1999)
  • Y Makonnen, ‘International law and the new states of Africa: a study of the international legal problems of state succession in the newly independent states of Eastern Africa’ (Ethiopian National Agency for UNESCO, Addis Ababa 1983)
  • DP O’Connell, ‘State Succession in Relation to New States’ (1970-II) 130 RdC 101
  • P Pazartzis, La Succession d’États aux Traités Multilateraux á la Lumière des Mutations Territoriales Récentes (Pedone, Paris 2002)
  • M Silagi, Staatsuntergang und Staatennachfolge (Lang, Frankfurt am Main 1996)
  • B Stern, ‘La Succession d’Etats’ (1996) 262 RdC 9
  • DF Vagts, ‘State Succession: The Codifiers’ View’ (1993) 33 VJIL 275
  • A Zimmermann, Staatennachfolge in völkerrechtliche Verträge (Springer, Berlin 2000)


1  VCSST (concluded 23 August 1978, entered into force 6 November 1996) 1946 UNTS 3, Art 2. This definition does not include cases involving a mere change of government (such as the change from the Soviet Union to the Russian Federation), a constitutional change combined with a name change (such as the change from the Czechoslovak Socialist Republic (CSSR) to the Czechoslovak Federative Republic (CSFR)), or the mere change in the State’s designation.

2  Cf H Grotius, De jure belli et pacis, lib II, cap ix, tit xii; see also DP O’Connell, ‘State Succession in Relation to New States’ (1970-II) 130 RdC 101et seq (quoting Aristotle’s Politics, noting that when a city lost its identity, its political successor was to bear the burden of paying the city’s debts).

3  A Zimmermann, Staatennachfolge in völkerrechtliche Verträge (Springer, Berlin 2000) 136.

4  DP O’Connell, The Law of State Succession (CUP, Cambridge 1956) 17 et seq (‘O’Connell 1956’).

5  DP O’Connell, ‘Reflections on the State Succession Convention’ (1979) 39 ZaÖRV 734et seq.

6  O’Connell 1956 (n 4) 34.

7  Cf these and further cases in M Huber, Die Staatensuccession: völkerrechtliche und staatsrechtliche Praxis im XIX. Jahrhundert (Duncker & Dumblot, Leipzig 1898); O’Connell 1956 (n 4) 16–74.

8  O’Connell 1956 (n 4) 4, 35 et seq; Zimmermann (n 3) 81 et seq.

9  Zimmermann (n 3) 82.

10  XJ Eudin and HH Fisher, Soviet Russia and the West, 1920–1927: A Documentary Survey (Stanford University Press, Stanford 1957) 6–14.

11  Cf R Aldrich and J Connell, The Last Colonies (CUP, Cambridge 1998); UNGA, ‘Report of the Special Committee on the Situation with regard to the Implementation of the Declaration on the Granting of Independence to Colonial Countries and Peoples for 2010’ (6 July 2010) 65th Session, UN Doc Supp No 23 (A/65/23).

12  On the relationship between the decolonization process and treaty succession before 1989, see generally M Craven, The Decolonization of International Law: State Succession and the Law of Treaties (OUP, Oxford 2007).

13  DF Vagts, ‘State Succession: The Codifiers’ View’ (1993) 33 VJIL 275, 277–80.

14  UN Conference on Succession of States in Respect of Treaties, First Session, Vienna, 4 April–6 May 1977, Official Records, vol I: Summary records of the plenary meetings and of the meetings of the Committee of the Whole (A/CONF.80/16); UN Conference on Succession of States in Respect of Treaties, Resumed Session, Vienna, 31 July–23 August 1978, Official Records, vol II: Summary records of the plenary meetings and of the meetings of the Committee of the Whole, UN Doc A/CONF.80/16/Add.1; UN Conference on Succession of States in Respect of Treaties, 1977 session and resumed session 1978, Vienna, 4 April–6 May 1977 and 31 July–23 August 1978, Official Records, vol III: Documents of the Conference, UN Doc A/CONF.80/16/Add.2.

15  ST Korman, ‘The 1978 Vienna Convention on Succession of States in Respect of Treaties: An Inadequate Response to the Issue of State Succession’ (1992) 16 Suffolk Transnat’l L Rev 174, 178.

16  D Türk, ‘The Dangers of Failed States and a Failed Peace in the Post Cold War Era’ (1995) 27 NYU J Intl L & Pol 625et seq.

17  The relevant number depends on whether Kosovo is counted as a new State.

18  MA Martins, ‘An Alternative Approach to the International Law of State Succession: Lex Naturae and the Dissolution of Yugoslavia’ (1993) 44 Syracuse L Rev 1019, 1020.

19  On 14 July 2011, the Republic of South Sudan was admitted to UN membership: UN Doc A/RES/65/308. Prior to South Sudan’s independence, a 2009 ‘handbook’ addressed the relevant problems of treaty succession. Cf Office of the President of the Government of Southern Sudan in collaboration with the Public International Law & Policy Group, South Sudan: A Guide to Critical Post-2011 Issues, Legal Handbook (December 2009). The handbook noted that the ‘Republic of Sudan will be considered the “continuing state” and Southern Sudan will be considered a newly independent or “successor state”’. The handbook also dealt with ‘continuing treaty obligations’, noting that:

[a]n examination of international legal principles demonstrates that a successor state … has the option of choosing which treaties signed by the predecessor/continuing state (the Republic of Sudan) it would like to uphold. However, based on recent state practice, the international community would likely expect an independent Southern Sudan to continue the Republic of Sudan’s treaty obligations. Exceptions to this presumption of continuity occur when: (1) both parties agree otherwise, (2) the treaty is not relevant to the new state’s territory, or (3) continuity would frustrate the treaty’s object and purpose.

The handbook suggested that South Sudan identify all treaties that fall under the listed exceptions and ‘thus would not continue to apply to Southern Sudan after independence’. Likewise, it suggested that South Sudan follow State practice and inform other States of its ‘intentions to abide by the terms of the predecessor State’s treaty obligations as part of the process of achieving international recognition and establishing diplomatic relations’. The handbook noted that ‘[i]n some instances, new states must also deposit an instrument of accession with the appropriate treaty depository to affirm a commitment to be bound by a treaty’s terms’.

20  See in more detail Part I.D, 403 et seq.

21  VCLT Art 73 (providing that the VCLT shall not prejudge any question that may arise in regard to a treaty from a succession of States); see also M Villiger, Commentary on the 1969 Vienna Convention on the Law of Treaties (Martinus Nijhoff, Leiden 2009) 895–904.

22  B Stern, ‘La Succession d’Etats’ (1996) 262 RdC 164–70.

23  ST Bernárdez, ‘The “Uti Possidetis Juris Principle” in Historical Perspective’ in K Ginther and others (eds), Völkerrecht zwischen normativem Anspruch und politischer Realität: Festschrift für Karl Zemanek zum 65. Geburtstag (Duncker & Humblot, Berlin 1994). The ICJ described the uti possidetis principle, ie the principle of the intangibility of frontiers inherited from colonization, as a ‘general principle, which is logically connected with the phenomenon of the obtaining of independence, wherever it occurs’. Case concerning the Frontier Dispute (Burkina Faso/Republic of Mali) [1986] ICJ Rep 554, 565.

24  Stern (n 22) 167 et seq.

25  As of 2012, twenty-two States are parties to the VCSST; fourteen others are signatories. The latest State to accede was the Republic of Moldova on 9 February 2009.

26  According to VCSST Art 49(1), the Convention entered into force on the thirtieth day following the date of deposit of the fifteenth instrument of ratification or accession.

27  Cf n 1 and accompanying text.

28  Cf Opinion No 1 of the Arbitration Commission of the Conference on Yugoslavia (Badinter Commission), 29 November 1991 [1992] 31 ILM 1494–7, 1(e); Award of the Arbitration Tribunal for the Determination of the Maritime Boundary between Guinea-Bissau and Senegal, 31 July 1989 (1992) RGDIP 265 (English translation available at <http://www.icj-cij.org/docket/files/82/11289.pdf>).

29  VCSST Art 6 provides: ‘The present Convention applies only to the effects of a succession of States occurring in conformity with international law and, in particular, the principles of international law embodied in the Charter of the United Nations.’

30  Thus, it has been noted that certain revolutionary governments were allowed not to respect entirely the obligations of their predecessors. Whether this was simply a consequence of negotiation or a case of succession is debatable. P Dailler, M Forteau, and A Pellet, Droit International Public (8th edn LGDJ, Paris 2009) 601.

31  VCSST Art 2(1)(c).

32  Cf VCSST Art 15.

33  Cf VCSST Art 2(1) on the use of terms.

34  Cf Craven (n 12) 29–51.

35  ILA, The Effect of Independence on Treaties: A Handbook (Stevens & Sons, London 1965).

36  This list is taken from Y Makonnen, International Law and the New States of Africa: A Study of the International Legal Problems of State Succession in the Newly Independent States of Eastern Africa (Ethiopian National Agency for UNESCO 1983) 129; cf also A Reinisch and G Hafner, Staatensukzession und Schuldenübernahme (Wien, Berlin 1995) 35.

37  Makonnen (n 36) 129.

38  Ibid 130. Makonnen associates this theory with Gabba, Appleton, and Gidel.

39  Ibid 131.

40  Ibid 132. This theory is also called the tabula rasa theory.

41  NV Zakharova, ‘O mezhdunarodnoi pravosub-ektnosti gosudarstv pri socialnoi revolucii’ (1960) Soviet Ybk of Intl L 157, 164; Makonnen (n 36) 133.

42  Makonnen (n 36) 137.

43  Ibid 142.

44  EG Bello, ‘Reflections on Succession of States in the Light of the Vienna Convention on Succession of States in Respect of Treaties of 1978’ (1980) German Ybk Intl L 296–7.

45  Makonnen (n 36) 133 with reference to a slightly modified theory of Keith according to whom rights would pass to the successor, but not obligations. AB Keith, The Theory of State Succession: With Special Reference to English and Colonial Law (Kessinger, London 1907) 5.

46  R Mullerson, ‘New Developments in the Former USSR and Yugoslavia’ (1993) 33 VJIL 299, 301.

47  AM Beato, ‘Newly Independent and Separating States’ Succession to Treaties: Considerations on the Hybrid Dependency of the Republics of the Former Soviet Union’ (1994) 9 Am U J Intl L & Pol’y 525, 536.

48  In this context, Degan discerns, on the one hand, a collectivist (solidariste) and, on the other, a voluntarist conception of international law. Cf VD Degan, ‘Création et disparition de l’Etat’ (1999) 279 RdC 205.

49  H Kelsen, Principles of International Law (Rinehart and Company, New York 1952) 296. Seen as such, the creation of new treaty relations can also be compared to the institution of subrogation relevant, in particular, to the international legal regime of investment protection. Cf O Udokang, Succession of New States to International Treaties (Oceana, Dobbs Ferry 1972) 109.

50  DP O’Connell, State Succession in Municipal Law and International Law (CUP, Cambridge 1967) vol II, 335.

51  Ibid 349 et seq.

52  Thus, it can even be asked whether a treaty subject to implementing legislation because of its non-self-executing nature remains applicable or requires new implementing legislation assuming the continuation of a treaty in relation to a new State. Cf ibid.

53  Cf the collection of recent practice in J Klabbers and others (eds), State Practice Regarding State Succession and Issues of Recognition: The Pilot Project of the Council of Europe (Kluwer, London 1999).

54  VCSST Art 2(1)(f).

55  The ILC considered the category of ‘newly independent states’ to include ‘any case of emergence to independence of any former dependent territories, whatever its particular type may be’, including ‘colonies, trusteeships, mandates, protectorates, etc’. Cf [1974] YBILC, vol II(1), 176; Zimmermann (n 3) 228 et seq. However, such States raise certain problems regarding the definition of their predecessor; so, for instance, the Vienna Conference on State Succession with Regard to Treaties adopted a resolution that denied South Africa the status as predecessor of Namibia. This resolution, nevertheless, did not decide which other State could qualify as such, whether it was Germany as the former colonial power of Namibia (‘Deutsch Südwest Afrika’) or whether it was Great Britain whose dominion South Africa was at that time, UN Doc A/CONF.80/32.

56  At its first session in 1949, the ILC did not give priority to the topic of State succession. [1968] YBILC, vol II, 213 [29]. At its 1962 session, however, prompted by UNGA resolution 1686 (XVI) of 18 December 1961, the ILC included on its priority list the topic of succession of States and governments.

57  Makonnen (n 36) 201; see also DP O’Connell, ‘Independence and Problems of State Succession’ in WV O’Brien (ed), The New Nations in International Law and Diplomacy (Stevens and Sons, London 1965) 7.

58  UN Doc A/CONF.117/14 (not yet in force).

59  But see n 229 and accompanying text with respect to the ILC’s current work on reservations.

60  RY Jennings and AD Watts (eds), Oppenheim’s International Law (9th edn Longman, London 1992) vol I, 227.

61  Cf generally in addition to subsequently cited more recent sources O’Connell (n 50).

62  O’Connell 1956 (n 4) 31 et seq and 54 et seq.

63  Zimmermann (n 3) 176 et seq.

64  Ibid 447 et seq.

65  R Mushkat, ‘Hong Kong and Succession of Treaties’ (1997) 46 ICLQ 181.

66  Zimmermann (n 3) 444 f.

67  Ibid 245–82.

68  Ibid 134 et seq.

69  Ibid 135 et seq.

70  Ibid 136.

71  Zimmermann (n 3) 137.

72  Ibid.

73  O’Connell 1956 (n 4) 21 et seq.

74  Ibid 22 et seq.

75  Zimmermann (n 3) 141 et seq.

76  S Jayakumar, ‘Singapore and State Succession: International Relations and Internal Law’ (1970) 19 ICLQ 398–423.

77  Zimmermann (n 3) 123 et seq.

78  See R Hofmann, ‘Annexation’ in R Wolfrum (ed), The Max Planck Encyclopedia of Public International Law (OUP, Oxford 2006) online edition at <www.mpepil.com> [1].

79  Ibid [5].

80  Cf notes 29–30 and accompanying text; Zimmermann (n 3) 24–36, who concludes that in the case of an illegal acquisition of territory a modified version of the rules of State succession apply.

81  E Cotran, ‘Some Legal Aspects of the Formation of the United Arab Republic and the United Arab States’ (1959) 8 ICLQ 346–90.

82  C Dunbar, ‘The Unification of Yemen: Process, Politics and Prospects’ (1992) Middle East J 456; R Goy, ‘La reunification du Yémen’ (1990) AFDI 249.

83  R Goy, ‘L’Independence de l’Erythrée’ (1993) AFDI 337–56.

84  Cf also in regard to the case of the former SFRY, Craven (n 12) 67–75.

85  See nn 15373 and accompanying text.

86  E Williamson and J Osborne, ‘A U.S. Perspective on Treaty Succession and Related Issues in the Wake of the Breakup of the USSR and Yugoslavia’ (1993) 33 VJIL 261.

87  Makonnen concludes that ‘thus the opinions of jurists (were) almost unanimous in holding that the clean-slate rule doctrine is most widely accepted and whatever contrary evidence is available in state practice (was) governed by treaties and by other political arrangements’. Makonnen (n 36) 129 (referring to authorities like Jenks, Lissitzyn, Bokor-Szegő, and McNair).

88  Beato (n 47) 525, 537.

89  According to the universalists who rely on Kant, international relations rest on the transnational bonds between individuals, all of whom share common interests. Cf ‘Taking Reichs Seriously: German Unification and the Law of State Succession’ (1990) 104 Harv L Rev 588, 602.

90  Thus, the US departed from the position laid down in the Restatement (Third) of the Foreign Relations Law of the United States (1987) in favour of considerations dictated by the need for stability of legal rights and obligations. Cf Williamson and Osborne (n 86) 264.

91  Udokang (n 49) 164.

92  Cf UN Legislative Series, Materials on Succession of States, UN Doc ST/LEG/SER.B/14.

93  See J Charney, ‘Universal International Law’ (1993) 87 AJIL 529, 536.

94  Treaty Section, UN Office of Legal Affairs, Summary of Practice of the Secretary-General as Depositary of Multilateral Treaties (UN, New York 1994), UN Doc ST/LEG/7/Rev. 1 (‘UN Depositary Practice’).

95  Ibid [303].

96  Cf Makonnen (n 36) 281.

97  K Zemanek, Gegenwärtige Fragen der Staatensukzession, Berichte der Deutschen Gesellschaft für Völkerrecht (CF Mueller, Karlshue 1964) 77.

98  Zimmermann (n 3) 155.

99  See [1962] YBILC, vol II, 122 [133] (discussed in A Watts, The International Law Commission, 1949–1998 (Clarendon Press, Oxford 1999) vol II(2), 1019).

100  See A Aust, Modern Treaty Law and Practice (2nd edn CUP, Cambridge 2007) 373.

101  On provisional application generally, see Chapter 9.

102  Zimmermann (n 3) 830.

103  See Y Makonnen, ‘State Succession in Africa: Selected Problems’ (1986-V) RdC 146–8.

104  See J Nyerere, ‘Problems of State Succession in Africa: Statement of the Prime Minister of Tanganyika’ (1962) 11 ICLQ 1211 f. (‘[W]e are willing on a basis of reciprocity to continue in force for a period of two years from Independence Day all valid bilateral treaties which would otherwise have ended when we became an independent State. During that two-year period we will negotiate with the States concerned with a view, where appropriate, to continuing or changing these treaties in a mutually acceptable manner. We are also willing and anxious that Tanganyika should play her role in the family of nations by participation not only in those multi-lateral treaties which the United Kingdom may have extended or applied to the territory of Tanganyika but also even in those not so applied. However, because of the wide range of subject-matter covered by such treaties and also of the difficulties of applying the interim solution proposed for bilateral treaties, we have considered that the simplest solution is to deal with each of these treaties by specific arrangements as soon as possible. We are, however, prepared on a basis of reciprocity to treat such instruments as being in force vis-a-vis other States who rely upon them in their relations with Tanganyika.’)

105  VCSST Art 15 (Succession in respect of part of territory) provides that:

When part of the territory of a State, or when any territory for the international relations of which a State is responsible, not being part of the territory of that State, becomes part of the territory of another State: (a) treaties of the predecessor State cease to be in force in respect of the territory to which the succession of States relates from the date of the succession of States; and (b) treaties of the successor State are in force in respect of the territory to which the succession of States relates from the date of the succession of States, unless it appears from the treaty or is otherwise established that the application of the treaty to that territory would be incompatible with the object and purpose of the treaty or would radically change the conditions for its operation.

106  Cf eg Stern (n 22) 169; Zimmermann (n 3) 823 et seq.

107  Cf Joint Declaration of the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the People’s Republic of China on the Question of Hong Kong (signed 19 December 1984) 1399 UNTS 61; Joint Declaration of the Government of the People’s Republic of China and the Government of the Republic of Portugal on the Question of Macao (signed 13 April 1987) 1498 UNTS 229.

108  See Part II.C.3, 412 et seq.

109  [1991] 30 ILM 463.

110  Ibid 472; JA Frowein, ‘The Reunification of Germany’ (1992) 86 AJIL 152, 158.

111  Cf with respect to consultations Klabbers and others (n 53) 88.

112  Cf certain exceptions in Zimmermann (n 3) 246–82.

113  See ILA Committee on Aspects of the Law of State Succession, ‘Draft Conference Report Rio de Janeiro Conference’ (2008) available at <http://www.ila-hq.org/en/committees/index.cfm/cid/11> 8–10; Zimmermann (n 3) 831.

114  Zimmermann (n 3) 283–5; O’Connell 1956 (n 4) 71 et seq; D Cottran, ‘Some Legal Aspects of the Formation of the United Arab Republic and the United Arab States’ (1959) 8 ICLQ 346; M Shaw, International Law (CUP, Cambridge 2008) 973.

115  VCSST Art 17(3) provides that ‘[w]hen, under the terms of the treaty or by reason of the limited number of the negotiating States and the object and purpose of the treaty, the participation of any other State in the treaty must be considered as requiring the consent of all the parties, the newly independent State may establish its status as a party to the treaty only with such consent’.

116  Agreement between the Yemen Arab Republic and the People’s Democratic Republic of Yemen on the Establishment of the Republic of Yemen (done 22 April 1990, entered into force 21 May 1990) translation in [1991] 32 ILM 820 (‘[T]here shall be established … a full and complete union, based on a merger, in which the international personality of each of them shall be integrated in a single international person called “the Republic of Yemen”’).

117  Ibid.

118  [1974] YBILC, vol II(1), 260–6.

119  Williamson and Osborne (n 86) 263 et seq.

120  Cf Klabbers and others (n 53) 100, 102.

121  See eg the list of bilateral treaties drawn up by Austria and the Czech Republic, ‘Promulgation of the Federal Chancellor concerning the bilateral treaties in force between the Republic of Austria and the Czech Republic’ (31 July 1997) Federal Law Gazette III No 123/1997. Similar lists have been annexed to agreements between other States, see ILA Committee Draft Report (n 113) 14.

122  In contrast, the United States and Ukraine concluded an international agreement detailing the terms of Ukraine’s succession to various US–USSR treaties. Agreement Concerning the Succession of Ukraine to Bilateral Treaties between the United States and the Former Union of Soviet Socialist Republics, with Annex (Exchange of notes at Kiev 10 May 1995) reprinted in (1995) 89 AJIL 761–2. See also S Cummins and D Stewart (eds), [2005] Digest of United States Practice in International Law 1991–1999 748–50.

123  Zimmermann (n 3) 831 et seq.

124  ILA Committee Draft Report (n 113) 27; Zimmermann (n 3) 831 et seq.

125  As to the history prior to the Second World War, see Beato (n 47) 548; D Lloyd, ‘Succession, Secession, and State Membership in the United Nations’ (1994) 26 NYU J Intl L & Pol 761, 757; Mullerson (n 46) 308; R Rich, ‘Recognition of States: The Collapse of Yugoslavia and the Soviet Union’ (1993) 4 EJIL 37.

126  Mullerson (n 46) 308.

127  Ibid 309; Korman (n 15) 174.

128  Vagts (n 13) 309; P Williams, ‘The Treaty Obligations of the Successor States of the Former Soviet Union, Yugoslavia, and Czechoslovakia: Do They Continue in Force?’ (1994) 23 Denv J Intl L & Pol 1, 2 (concerning the reluctant recognition by the Soviet Union). As to doubts on Statehood before 1991, see Lloyd (n 125) 776.

129  Mullerson (n 46) 309.

130  Lloyd (n 125) 778.

131  Mullerson (n 46) 310.

132  Those States were Ukrainskaya SSR, Byelorusskaya SSR, Azerbaijanskaya SSR, Armyanskaya SSR, Gruzinskaya SSR, Kazakhskaya SSR, Turkmenskaya SSR, Uzbekistanskaya SSR, Tajikistanskaya SSR, Kyrgyzstanskaya SSR, and Moldovskaya SSR.

133  In the Ukraine, 90 per cent of the population voted in favour of independence. Williams (n 128) 2.

134  [1992] 31 ILM 145 (Art 12).

135  Ibid 149; Rich (n 125) 44.

136  [1992] 31 ILM 147. However, the Declaration of Alma Ata made the continued legal force of treaties dependent on compatibility with the relevant ‘constitutional procedures’.

137  Cf Klabbers and others (n 53) 96.

138  Mullerson (n 46) 309; L Love, ‘International Agreement Obligations after the Soviet Union’s Break-Up: Current United States Practice and its Consistency with International Law’ (1993) 26 Vand J Transnat’l L 373, 384.

139  Cf Rich (n 125) 40.

140  HJ Uibopuu, Die Völkerrechtssubjektivität der Unionsrepubliken der UdSSR (Springer, Vienna 1975) 275et seq; Love (n 138) 389.

141  This practice accords with VCSST Art 35, which provides that in the case of separation and subject to limited exceptions when ‘the predecessor State continues to exist, any treaty which at the date of the succession of States was in force in respect of the predecessor State continues in force in respect of its remaining territory’.

142  Mullerson (n 46) 305.

143  Klabbers and others (n 53) 98 et seq.

144  Mullerson (n 46) 311 et seq; Beato (n 47) 550. The Baltic States argued in this sense irrespective of the non-applicability of the treaty succession regime to their situation.

145  Cf U Saxer, ‘The Transformation of the Soviet Union: From Commonwealth Socialist Federation to a Commonwealth of Independent States’ (1992) 14 Loy LA Intl & Comp L J 581, 674.

146  Cf USSR Constitution (1977) Art 10.

147  Even in this respect it must be asked how far the parties of these Union Republics were represented in the inner circles of the CPSU.

148  Beato (n 47) 554.

149  Cf [1968] BILC, vol II, 17; cf also on the link between newly independent States and the so-called ‘salt-water’ colonies, Craven (n 12) 15.

150  Cf somewhat more restrictively Zimmermann (n 3) 825.

151  UN Depositary Practice (n 94) [303].

152  Zimmermann (n 3) 831–2; This understanding was also reflected eg in the opinion of the ECJ’s General Advocate Tizzano in Case C-216/01, Budějovický Budvar, národní podnik v Rudolf Ammersin GmbH (Opinion of Advocate General Tizzano) ECR 2003 I-13617.

153  Rich (n 125) 38.

154  Cf UNSC Res 757 (1992).

155  Cf (1993) 4 EJIL 80. The ‘Badinter’ EC Arbitration Commission was an organ of the Conference on Yugoslavia, convened by the European Community in 1991 and tasked with giving advisory opinions, inter alia, relating to questions of State succession arising during the process of the SFRY’s disintegration. See eg M Craven, ‘The European Community Arbitration Commission on Yugoslavia’ (1996) BYBIL 333–413.

156  Williams (n 128) 4.

157  Lloyd (n 125) 780.

158  In Opinion No 4, the EC Arbitration Commission declared Bosnia Herzegovina as having not yet achieved the status as a ‘sovereign and independent State’. (1993) 4 EJIL 74.

159  UNGA Res 46/237 (22 May 1992).

160  UNGA Res 47/225 (8 April 1993); Williams (n 128) 4.

161  In contrast to the findings concerning Bosnia Herzegovina, the EC Arbitration Commission took the view in its Opinion No 6 that Macedonia satisfied the tests of the Guidelines on the Recognition of New States adopted by the Council of the European Communities on 16 December 1991. (1993) 4 EJIL 77 et seq.

162  Lloyd (n 125) 780.

163  Williams (n 128) 29; cf also the Case Concerning the Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Bosnia and Herzegovina v Serbia and Montenegro) (‘Bosnian Genocide Case’) (Provisional Measures) [1993] ICJ Rep 3, 15.

164  Cf (1993) 4 EJIL 80.

165  UNSC Res 777 (1992).

166  Williams (n 128) 40.

167  See Opinion No 10 of the EC Arbitration Commission. (1993) 4 EJIL 90.

168  UNGA Res 55/12 (10 November 2000).

169  Cf ICJ, Accordance with International Law of the Unilateral Declaration of Independence in Respect of Kosovo (Advisory Opinion) 2010 <http://www.icj-cij.org/docket/files/141/15987.pdf>.

170  See Part II.A, 408 et seq.

171  Cf Art 3 Republic of Slovenia Assembly Constitutional Law of the Enforcement of the Basic Constitutional Charter on the Autonomy and Independence of the Republic of Slovenia (25 June 1991) in S Trifunovska (ed), Yugoslavia Through Documents: From its Creation to its Dissolution (Martinus Nijhoff, Dordrecht 1994) 292–8; Williams (n 128) 38 et seq.

172  Doc CAHDI (93)11 of 12 August 1993, 7; see also Williams (n 128) 16 et seq.

173  Williams (n 128) 33.

174  Ibid 7.

175  ‘Proclamation of the National Council of the Slovak Republic to the Parliaments and Peoples of the World’ (2 December 1992) in UNGA, ‘Letter Dated 31 December 1992 from the Permanent Representative of Czechoslovakia to the United Nations Addressed to the Secretary-General’ UN Doc A/47/848, Annex II.

176  ‘Proclamation of the Czech National Council to all Parliaments and Nations of the World’ (17 December 1992) in UNGA, ‘Letter Dated 31 December 1992 from the Permanent Representative of Czechoslovakia to the United Nations Addressed to the Secretary-General’ UN Doc A/47/848 Annex I.

177  Ústavní zákon České národní rady o opatřeních souvisejících se zánikem České a Slovenské Federativní Republiky (Constitutional Law of the Czech National Council on Measures Connected with the Dissolution of the CSFR) (done 15 December 1992) č 4/1993 Sb.

178  Constitution of the Slovak Republic (Slovakia) No 466/1992 Coll.

179  Case Concerning the Temple of Preah Vihear (Cambodia v Thailand) (Merits) [1962] ICJ Rep 6, 34.

180  [1968] YBILC, vol II, 92–3.

181  Cf Frontier Dispute (Burkina Faso/Republic of Mali) [1986] ICJ Rep 554, 567; Territorial Dispute (Libyan Arab Jamahiriya/Chad) [1994] ICJ Rep 6 ff 38; Opinion No 3 of the Arbitration Commission of the Conference on Yugoslavia (Badinter Commission) [1992] 31 ILM 1499 f; Cf also ILA Committee Draft Report (n 113).

182  Zimmermann (n 3) 490.

183  Bernárdez (n 23) 418.

184  Love (n 138) 378.

185  Ibid.

186  [1974] YBILC, vol II(1), 83.

187  Ibid 204.

188  ILC, ‘Report on Succession of States’ [1974] YBILC, vol II(1), 206; see also ILA, Effect of Independence on Treaties (1965) 352.

189  Case concerning the Gabčíkovo-Nagymaros Project (Hungary/Slovakia) (Judgment) [1997] ICJ Rep 7 [123].

190  Ibid.

191  See also the respective positions of the US and the UK at the Vienna Conference in Craven (n 12) 196 et seq. The doctrine of acquired rights broadly entails that a legal right or status acquired under domestic law must be respected as an international obligation. Cf eg F Francioni, ‘Compensation for Nationalisation of Foreign Property: The Borderland between Law and Equity’ (1975) ICLQ 255, 258.

192  NJ Schrijver, Sovereignty over Natural Resources: Balancing Rights and Duties (CUP, Cambridge 1997, reprinted CUP 2008) 377.

193  International Covenant on Civil and Political Rights (adopted 19 December 1966, entered into force 23 March 1976) 999 UNTS 171; International Covenant on Economic, Social and Cultural Rights (adopted 16 December 1966, entered into force 3 January 1976) 993 UNTS 3.

194  A Trindade, ‘International Law for Humankind: Towards a New Jus Gentium’ (2005) 317 RdC 108et seq.

195  Article 12bis of the ILC draft had originally foreseen automatic succession in respect of certain universal multilateral treaties, including particularly human rights treaties. [1974] YBILC, vol II(1), 172.

196  ILA Committee Draft Report (n 113) 33.

197  See on this issue A Rasulov, ‘Revisiting State Succession to Humanitarian Treaties: Is There a Case for Automaticity?’ (2003) 14 EJIL 141–70 (concluding that ‘in international law, the treaties of humanitarian character are not subject to automatic succession’ but favouring transformation of the acquired rights theory so that obligations arising from a human rights treaty are not affected by State succession).

198  See n 202 and accompanying text.

199  See nn 2048 and accompanying text.

200  Application of the Convention on the Prevention and Punishment of the Crime of Genocide (Croatia v Serbia) Judgment (Preliminary Objections) [2008] ICJ Rep 412 [117].

202  Čelebići Case (Prosecutor v Delacic et al) [2001] ICTY Case No IT-96-21-A [111]–[113].

203  Ibid [112]–[113].

204  Eritrea Ethiopia Claims Commission, Partial Award, Prisoners of War, Ethiopia’s Claim 4 (The Federal Democratic Republic of Ethiopia v The State of Eritrea), The Hague, 1 July 2003 [24].

205  Ibid.

206  Ibid.

207  Ibid.

208  Ibid.

209  Convention on the Prevention and Punishment of the Crime of Genocide (adopted 9 December 1948, entered into force 12 January 1951) 78 UNTS 277.

210  P Gaeta (ed), The UN Genocide Convention: A Commentary (OUP, Oxford 2009) 493.

211  Ibid.

212  Cf VCSST Arts 31(3), 32(6), 30(3)(a), 33(5), 34(2)(b), 35(c), 36(3), 37(2).

213  Jennings and Watts (n 60) 211.

214  Korman (n 15) 180.

215  See I Buffard and K Zemanek, ‘The “Object and Purpose” of a Treaty: an Enigma?’ (1998) ARIEL 311–43.

216  See nn 10911 and accompanying text.

217  VCSST Art 17(3) provides: ‘When, under the terms of the treaty or by reason of the limited number of the negotiating States and the object and purpose of the treaty, the participation of any other State in the treaty must be considered as requiring the consent of all the parties, the newly independent State may establish its status as a party to the treaty only with such consent.’ Moreover, the VCSST frequently refers explicitly to this provision: elsewhere in Art 17 on multilateral treaties and in Arts 29, 30, 31, 32, 33, 36, and 37. The latter articles do not relate to newly independent States, so this restriction must be considered generally applicable.

218  UN Depositary Practice (n 94) [297].

219  Ibid [295] (‘The provisions of a treaty may even totally rule out succession. Such would be the case if the treaty was open only to the participation of the members of a regional commission which itself would not be open to the new State. In such cases, the situation is clear and the Secretary-General simply abides by the provisions of the treaty’).

220  See generally K Bühler, State Succession and Membership in International Organizations: Legal Theories versus Political Pragmatism (Martinus Nijhoff, London 2001).

221  Cf O’Connell (n 57) 183–211.

222  Bühler (n 220) 289.

223  VCSST Art 4 provides in this regard that the ‘Convention applies to the effects of a succession of States in respect of: (a) any treaty which is the constituent instrument of an international organization without prejudice to the rules concerning acquisition of membership and without prejudice to any other relevant rules of the organization; (b) any treaty adopted within an international organization without prejudice to any relevant rules of the organization’.

224  Vagts (n 13) 292–3.

225  Zimmermann (n 3) 746 et seq.

226  VCSST Art 20 provides that ‘[w]hen a newly independent State establishes its status as a party or as a contracting State to a multilateral treaty by a notification of succession under article 17 or 18, it shall be considered as maintaining any reservation to that treaty which was applicable at the date of the succession of States in respect of the territory to which the succession of States relates unless, when making the notification of succession, it expresses a contrary intention or formulates a reservation which relates to the same subject matter as that reservation’.

227  Zimmermann (n 3) 770.

228  Ibid 771.

229  See eg A Pellet (Special Rapporteur), ‘Sixteenth report on reservations to treaties: Status of reservations, acceptances of and objections to reservations and interpretative declarations in the case of succession of States’, 19 March 2010, UN Doc A/CN.4/626; in 2011, the ILC’s work on the topic has culminated in a Guide to Practice on Reservations to Treaties, UN Doc A/66/10 19-49.

230  Ibid (Guide to Practice Section 5).

231  Zimmermann (n 3) 832.

232  Ibid 833.

233  Ibid 785 et seq.

234  On South Sudan see n 19; S Salman, ‘The New State of South Sudan and the Hydro-Politics of the Nile Basin’ (2011) 36 Water Intl 154–66.