1. Introduction
Relations between the Republic of Serbia and KosovoFootnote 1 are delicate and complex. They are influenced by a myriad of factors and the reduction to a single one is bound to be unappreciative towards the complex roots of such relations. Under this disclaimer, the aim of this research is to highlight a specific facet of the aforementioned relationship by examining the manner in which the Republic of Serbia endeavours to safeguard its national interest concerning Kosovo in the framework of international law and by using mechanisms of international law. In February 2008, Kosovo declared its independence from the Republic of Serbia and its statehood has until today been recognized by around 100 member states of the United Nations.Footnote 2 In terms of a national interest, Serbia regards Kosovo as part of its territory, thus rejecting its proclaimed statehood and hindering its independence through the rejection of its recognition. To advance such position, Serbia has pursued several international legal avenues.
Serbia contested Kosovo’s statehood by resorting to both judicial and diplomatic means of peaceful settlement of disputes; Serbia initiated the UN General Assembly’s request for the International Court of Justice’s Advisory Opinion on the matter;Footnote 3 and as part of its diplomatic actions, Serbia has undertaken efforts to either dissuade states from recognizing Kosovo’s statehood or to encourage the withdrawal of recognition if the states had previously recognized it as an independent state.Footnote 4 Serbia has also been trying to advance its national interest by impeding Kosovo’s membership in international organizations of political character.Footnote 5 Serbia and Kosovo have been directly engaged in different bilateral and multilateral relations pertinent to international law. Since 2011, Serbia and Kosovo have been part of the European Union-led negotiation process which resulted in several agreements being concluded between them: the 2013 Brussels AgreementFootnote 6 and the 2023 Brussels-Ohrid AgreementFootnote 7 .
Finally, Serbia and Kosovo are both parties to several multilateral international treaties. However, legal implications of this fact have not been previously examined. Scholars have confirmed that the common participation of non-recognizing entities in a multilateral treaty does not amount to recognition.Footnote 8 Still, the recognition is not the only legal relation that can be understood to be established between such two entities under the multilateral treaty framework, as certain rights and obligations can also be created between them without the recognition. Therefore, it is necessary to explore which international legal tools can define relations between the two non-recognizing parties to a treaty in a multilateral treaty framework.
The theoretical framework of this study is based on the premise that international law functions both as a normative and a regulatory system and as an argumentative practice.Footnote 9 The regulatory aspect is rooted in the principle of cooperation and is outcome-oriented, focusing on achieving desirable material results and resolving or preventing disputes.Footnote 10 The argumentative practice aspect, on the other hand, allows for a conflict to be seen as an inherent part of international law, emphasizing the process of ‘arguing without resolution’.Footnote 11 In this view, the interests of individual states (national interests) are ackowledged and are not necessarily seen as opposed to the common interest. As Higgins puts it: ‘An efficacious legal system can also contain competing interests, allowing those who hold them not to insist upon immediate and unqualified vindication.’Footnote 12 The argumentative practice enables cooperation despite disagreements and explains why states strategically use international law in international relations beyond the quest to ensure the compliance with the legal rules.Footnote 13
This strategic use of international law goes beyond the normative role and encompasses its rhetorical and justificatory functions.Footnote 14 Specifically, international law does not only define correct and incorrect state behaviour but also ‘provides a positive common language for the communication of members in international society’Footnote 15 and acts as a means to align particular national interest with a general interest in international relations.Footnote 16 In the words of Reed: ‘As a justificatory tool, international law gives actors a unique rhetorical source to draw on as they aim to portray their behaviors as appropriate to broader audiences.’Footnote 17
This study will focus on exploring these communicative and legitimizing roles of international law,Footnote 18 with an emphasis not on the functions of primary rules (which determine the substance and meaning of a legal norm) but on the functions of secondary rules (which govern the process of lawmaking, in this case, treaty lawmaking).Footnote 19 Secondary rules of international treaty law which states can employ strategically to safeguard their national interests in the framework of a multilateral treaty include several instruments: statements of exclusion, objections to accession, engaging with a depositary of a treaty and the application of the territorial clause of a treaty. The empirical study will concentrate on the Serbia’s position towards Kosovo within multilateral treaties to which both are the parties, analysing how Serbia utilizes these instruments in a communicative and legitimizing manner to advance its national interest as previously defined.Footnote 20
The article is organized as follows: Section 2 will briefly sketch legal consequences arising from the common participation in a multilateral treaty of two entities of which one does not recognize the other. Section 3 will turn to four tools pertinent to international treaty law that Serbia used when Kosovo acceded to multilateral agreements to which Serbia was already a party. Section 4 will conclude.
2. Common participation in multilateral treaties – Recognition v. establishment of legal relations
Consent is the cornerstone of international treaty law. States need to provide consent both to be bound by a treaty (the material domain of consent) and to enter into relations with other parties to a treaty (the personal domain of consent).Footnote 21 In the case of bilateral treaties, the material and personal domain of consent overlap. However, in multilateral treaties, consent to be bound by a treaty does not necessarily mean that a state expresses consent to be bound in relations to every other party to the treaty. Therefore, the material and personal domain of consent might differ; however, they are both given in a form of a unilateral act. In order for relations under a multilateral treaty to be established, commitments through unilateral acts need to be mutual between at least three parties.Footnote 22 Hence, the unilaterality of consent to be bound needs to be accompanied by the mutuality of commitments.
Article 11 of the 1969 Vienna Convention on the Law of Treaties (VCLT) provides for the well-established means to express consent in the material domain.Footnote 23 Expressing the scope of the personal domain of consent is however not institutionalized nor codified in the VCLT – states do it in the form of communications, declarations, opposing statements, reservations, or objections. A state can express its consent in the personal domain in two instances: on the occasion of its expression of consent to be bound by that treaty; or later, being already a party to a multilateral treaty in wishing to determine the nature of its relations with a new party acceding to the treaty. States that are already members to a multilateral treaty do not have their say in whether another party will join the treaty (it is the unilateral expression of the will of the acceding party); however, they can have their say in whether they will be bound towards that party under the relevant treaty. In this case, the mutual nature of commitments under a multilateral treaty could be in collision with the unilateral nature of the expression of consent. More precisely, the clash between two unilateral acts – the unilateral act of the acceding party, expressing its consent to be bound by the treaty and the unilateral act of the contesting state, expressing its hesitation to become bound by the treaty in relation to the acceding party – hinders mutuality.
There are several examples in practice that testify to the situation in which existing state parties expressed concerns regarding the accession of non-recognized entities. More recent examples include the accession of Palestine and Kosovo in 2015 to the Convention for the Pacific Settlement of International Disputes (1907 Hague Convention). State parties that did not recognize them as independent states filed declarations to the depositary in order to contest the accession. Canada, Israel, and the United States of America (the US) claimed that Palestine did not qualify as a sovereign state under international law, that it lacked the capacity to accede to the Convention and that they would not consider themselves to be in treaty relations with Palestine. Ecuador, Georgia, Mexico, Russian Federation, Spain, and Ukraine claimed that they did not recognize Kosovo as an independent state and that they were not bound by the Convention in relations with Kosovo.Footnote 24 As the examples show, when a party not recognized as an independent state by existing treaty members accedes to a multilateral treaty, legal effects of such joint participation can be assessed from two aspects: (i) whether the common participation amounts to recognition; and (ii) whether bilateral treaty relations, implying the establishment of rights and obligations under the treaty between the state party and the non-recognized entity, are established.Footnote 25 These two aspects will be analysed in turn.
Common participation in multilateral treaties of non-recognizing entities can be assessed through the prism of recognition, namely whether such joint participation amounts to (implicit) recognition. The scholarship established early on that membership to a same multilateral treaty did not constitute a recognition.Footnote 26 A century old example is the joint participation of the US and the Union of Soviet Socialist Republics (the USSR) in several multilateral treaties, including the International Sanitary Convention and the General Pact for the Renunciation of War in a period when the US did not recognize the Government of the USSR. While the issue revolved around the non-recognition by the US of the Government of the USSR, the doctrinal argumentation was clear in the stance that non-recognizing governments can have established legal relations and that such ‘extended dealings between two governments’ did not constitute a recognition.Footnote 27 This principle was later applied by analogy to state (non) recognition. It has been confirmed in the practice of the Committee on the Elimination of Racial Discrimination (CERD), in the Inter-State Communication Submitted by the State of Palestine against Israel, stating that ‘according to a well-established practice, a State’s participation in a treaty to which an entity that it does not recognize as a State is a party does not amount to recognition’.Footnote 28
Without amounting to recognition, the common participation of non-recognizing entities in multilateral treaties usually creates bilateral treaty relations, thereby establishing rights and obligations between the two parties.Footnote 29 However, this is not the absolute rule. In a case when one party does not give its consent to be bound by the treaty towards the other party, for any reason whatsoever, the bilateral treaty relations under the multilateral treaty cannot be established. This rule is rooted in the consensual nature of the treaty law and has been recognized by the CERD:
the Committee acknowledges that in general international law, treaty relations are based on consent, being the principle of free consent universally recognized. The Committee acknowledges that under general international law, a State party to a multilateral treaty may exclude treaty relations with an entity it does not recognize, through a unilateral statement.Footnote 30
This means that the unilateral action of one state party can exclude the establishment of bilateral relations under the multilateral treaty with the other party. Such unilateral statement serves two purposes: to express the new will of the excluding party which is to prevail over its previously expressed will at the time of giving the material domain of consent, and to narrow consent in terms of the personal domain, previously given to all other parties to a treaty.Footnote 31
Examples of a unilateral exclusion of bilateral treaty relations under a multilateral treaty can be found in state practice. Turning to the already mentioned case of the US and the USSR, when signing the International Sanitary Convention in 1926, the US filed a declaration with the effect of excluding the establishment of treaty relations with a ‘Power represented by a régime or entity which the United States does not recognize as representing the government of that Power … ’.Footnote 32 When Palestine acceded to the 1907 Convention Respecting the Laws and Customs of War on Land in 2014, the US filed a notification in which they stated, among other things:
The Government of the United States of America does not believe the “State of Palestine” qualifies as a sovereign State and does not recognize it as such. Accession to the Convention is limited to sovereign States. Therefore, the Government of the United States of America believes that the “State of Palestine” is not qualified to accede to the Convention and affirms that it will not consider itself to be in a treaty relationship with the “State of Palestine” under the Convention.Footnote 33
Sakran and Hayashi note that such reactions to the accession of Palestine to multilateral treaties became habitual in the practice of Canada, the US, and Israel.Footnote 34
It has therefore been established that international law and practice enable the common participation in multilateral treaties of two non-recognizing entities. Such common participation does not entail recognition but can entail establishment of bilateral treaty relations. However, norms of international law and state practice enable the unilateral exclusion of bilateral relations under a multilateral treaty. The following part of the article will elaborate on such a claim through a practical example and by its application to the case of Serbia’s and Kosovo’s common participation in multilateral treaties.
The issue of Serbia’s and Kosovo’s common participation in multilateral treaties became topical after the Kosovo’s Declaration of Independence in 2008. Even before the Declaration of Independence, Serbia and Kosovo had jointly been members of multilateral treaties (e.g. the Central European Free Trade Agreement), but Kosovo had been represented by the United Nations Interim Administration Mission in Kosovo (UNMIK).Footnote 35 Following the Declaration of Independence in 2008, Kosovo embarked on a trail to enter the international arena independently, and with that goal in mind, the participation in international agreements was enshrined in Kosovo’s Constitution (Article 17). Papić notes that this provision, whose inclusion is otherwise redundant in the case of sovereign states, had been the result of Kosovo’s peculiar legal position towards UNMIK. This is because under the Constitutional Framework for Kosovo, UNMIK had been given an exclusive competence for concluding agreements.Footnote 36 To corroborate its independence, after 2008, Kosovo acceded to several multilateral treaties.Footnote 37 These treaties included: the Articles of Agreement of the International Monetary Fund on 29 June 2009, the Convention Abolishing the Requirement of Legalisation for Foreign Public Documents (the Apostille Convention) on 6 November 2015, the Convention for the Pacific Settlement of International Disputes (1907 Hague Convention) on 6 November 2015, and the Convention Establishing a Customs Co-operation Council on 25 January 2017.Footnote 38 Apart from the 1907 Hague Convention, Serbia had already been a party to these multilateral treaties and its bilateral relations with Kosovo needed to be defined.Footnote 39 The following part of the research will explore international treaty law tools that Serbia utilized in order to define its bilateral relations with Kosovo in line with its national interest of safeguarding its territorial integrity and contesting Kosovo’s proclaimed statehood.
3. Using treaty law instruments in states’ common participation in multilateral treaties with non-recognized entities
The first multilateral treaty to which Kosovo acceded on 29 June 2009, in which Serbia had already been a party, was the Articles of Agreement of the International Monetary Fund.Footnote 40 On that occasion, Serbia directed a diplomatic note to the Government of the US, the depositary of the Agreement, containing the following declaration:
The Republic of Serbia declares that acts of signing and depositing purported instrument of accession to the Articles of Agreement of the International Monetary Fund by the representatives of the so-called “Republic of Kosovo” are in violation of international law and in particular United Nations Security Council resolution 1244. Consequently, they are null and void and without any legal effect. The Autonomous Province of Kosovo and Metohija is part of the Republic of Serbia currently under United Nations administration pursuant to Security Council resolution 1244 (1999).Footnote 41
The aim of this declaration was not only to hinder any possible recognition of Kosovo by Serbia or establishment of mutual legal relations between the two, but also to declare that the very act of Kosovo’s participation in the treaty is ‘null and void’ in absolute terms, thereby affecting Kosovo’s relations with the other states.
On the same occasion, only two other states submitted declarations: Romania and Slovakia. However, the substance, scope, and the anticipated legal effects of their declarations differed considerably: Romania only reiterated that it does not recognize Kosovo, while the claim of Slovakia was even more vague:
the admittance of “the Republic of Kosovo”, as a member of the International Monetary Fund … does not prejudge the position of the Slovak Republic on the status of Kosovo under United Nations Security Council Resolution 1244/99, which will be decided in accordance with national practice and international law.Footnote 42
These different reactions of three states, that otherwise share the position on the non-recognition of Kosovo, reflect the scope of an action that a state can pursue regarding the accession of a non-recognized entity to a multilateral treaty. The possible varieties of actions of non-recognizing states will now be presented, starting from the division between non-recognizing states that choose not to react and those which do, and then turning to the scope of actions of the latter.
First of all, a non-recognizing state does not have any legal obligation to act when an entity it does not recognize accedes to a multilateral treaty to which it is already a party. When Kosovo acceded to the Articles of Agreement of the International Monetary Fund there were several states which did not recognize it as a state, but only three states expressed their protest. States that do not recognize an acceding entity but take no action in that regard are in literature termed ‘the silent states’.Footnote 43 Second, non-recognizing states that do decide to act have a choice in terms of the scope, substance, and legal effects of their unilateral declaration. As it has been shown, Slovakia had not explicitly mentioned the recognition, while Romania had. However, both states had not actually protested to the establishment of bilateral relations with Kosovo. On the other hand, Serbia had contested not only the recognition and the establishment of bilateral relations, but the capacity of Kosovo to even be a party to the Agreement. This implied Serbia’s position that Kosovo’s membership is null and void in regards to other states as well.Footnote 44
Based on the presented example, we can discern at least four types of non-recognizing state parties’ reactions towards the accession of a not-recognized entity: (i) non-recognizing silent states; (ii) state parties expressly opposing recognition; (iii) state parties opposing the establishment of bilateral relations; (iv) state parties opposing participation in the treaty as such. ‘Direct’ and ‘indirect’ legal effects of these (re)actions will be scrutinized in the following part.
In terms of ‘direct’ legal effects, ‘silent states’ and states expressly opposing the recognition are in the same position towards a new entity – they do not recognize the entity, yet they do enter into rights and obligations with the entity. States that nevertheless decide to underline their non-recognition practice, do so in the form of a ‘precautionary statement’. The International Law Commission’s 2011 Guide to Practice on Reservations to Treaties (the ILC 2011 Reservations Guide) explains that
in some cases, the author of the statement is simply taking a “precautionary step” by pointing out that, in accordance with a well-established practice, its participation in a treaty to which an entity that it does not recognize as a State is a party does not amount to recognition.Footnote 45
Kolb explains that ‘[t]he statement is thus merely of a political nature. It is made either on account of ignorance of the law or ex abundante cautela, or else to show political correctness.’Footnote 46 While this is true, it can also be added that states decide to submit such statements in order to avoid any ambiguity regarding their position towards a non-recognized entity.Footnote 47 Moreover, ‘indirect’ legal effects can also be attributed to these statements. First, they reaffirm a legal principle that joint participation in a multilateral treaty does not constitute recognition. Second, they convey a state’s political stance through international legal mechanisms, effectively utilizing international law as the lingua franca of international relations and thereby enhancing its communicative function. Through this communicative practice, the state seeks to justify and legitimize its actions, in order to indirectly influence the behavior of other actors in international relations regarding the (non)recognition of contested entities.Footnote 48
As for the states that oppose participation of a non-recognized entity in a treaty as such, their unilateral action is devoid of the general ‘direct’ legal effect. Namely, one state cannot make a claim in the name of other states. Kolb states that in the decentralized international society ‘[e]ach treaty party must come to its own view as to the nature of a specific entity and its ability to become a party to treaty relations’.Footnote 49 Sakran and Hayashi add that states are free to express their opinion regarding the accession to a treaty of a contested entity, but that ‘these statements do not bind any other party to the treaty in question’.Footnote 50 Moreover, states’ unilateral contestation of the accession to a multilateral treaty of a non-recognized entity does not bear any legal effect on the actual membership of the entity in the treaty. However, we can discern the ‘indirect’ legal significance of such statements: states are eager to communicate their position to other actors and to present their interests as compatible with the rules of international law. This is illustrated by stressing the violation of international law and the UN Security Council resolution in the previously quoted diplomatic note of Serbia regarding the accession of Kosovo to the Agreement on IMF.
The only action that provokes ‘direct’ legal effects in practice is the unilateral declaration through which a non-recognizing state contests the establishment of bilateral relations with a non-recognized entity. This position leads to the exclusion of bilateral relations thereby affecting the scope of the multilateral agreement and the legal relations between the two entities.
By analysing the case study of Serbia, it has been discerned that a reaction of non-recognizing state parties to a multilateral treaty on the occasion of the accession of a non-recognized entity can be conveyed through several instruments pertinent to international treaty law: statements of exclusion, objections to accession, engaging with a depositary of a treaty and the application of the territorial clause of the treaty. These instruments are at the disposal of interested state parties in order to advance their national interests with regard to a non-recognized new treaty party. Since these instruments are the result of a state practice and are not listed in any existing document, it is essential to present and provide a more detailed explanation of each of them, as well as outline legal effects that arise from their usage.
3.1. Statements of non-recognition: Precautionary statements and statements of exclusion
In its 2011 Reservations Guide, the ILC defined ‘statements of non-recognition’ in order to expressly exclude them from the scope of the Guide and from the definition of a reservation.Footnote 51 The ILC defined statements of non-recognition as ‘[a] unilateral statement[s] by which a State indicates that its participation in a treaty does not imply recognition of an entity which it does not recognize’.Footnote 52 Such a statement is exempt from the reservation regime ‘even if it purports to exclude the application of the treaty between the declaring State and the non-recognized entity’.Footnote 53 This definition indicates that the ILC subsumed two different types of statements under the statements of non-recognition: ‘clean’ statements of non-recognition (‘precautionary statements’) and the objections to establishment of bilateral relations (‘statements of exclusion’).Footnote 54
In terms of the legal nature of statements of non-recognition, there is a uniform understanding that precautionary statements are not reservations. They ‘do not purport to have an effect on the treaty or on its provisions’Footnote 55 and have only a declaratory effect.Footnote 56 On the other hand, there is an ambiguity as to whether the statements of exclusion are to be considered reservations. Kolb expresses the view that a statement of exclusion is a reservation because ‘it impacts on the rights and obligations under the treaty, excluding them with regard to one or more treaty partners’.Footnote 57 The ILC’s position is to a certain extent in line with such view,Footnote 58 although they add that the exclusion of the treaty is done ‘only in the relations between the declaring State and the non-recognized entity’Footnote 59 , therefore excluding the statement from the reservations regime.
Turning back to definition of the reservation stricto sensu, its objective is to contest the legal effect of certain treaty provision(s) and the pertaining modification of legal effects of the contested provision(s) towards the party that is submitting the reservation. The ILC’s position does acknowledge that the reservation can provide relational effect towards another partyFootnote 60 ; they, however, posit that the statement of exclusion ‘do[es] not concern the legal effect of the treaty itself or its provisions, but rather the capacity of the non-recognized entity to be bound by the treaty’.Footnote 61 It is this characteristic that prevents the treatment of statements of exclusion as treaty reservations. Moreover, the ILC explained the practical impossibility of applying the reservation regime to such statements.Footnote 62
In order to support the conclusion reached by the ILC about the differentiation between reservations and statements of exclusion, we can consider the previously outlined unilateral statement of Serbia upon the accession of Kosovo to the Articles of Agreement of the International Monetary Fund. It is clear that the main aim of the statement was directed at contesting Kosovo’s capacity to be bound by the treaty and not towards the legal effect of the treaty provisions to Serbia. If it were a reservation, it should have been given at the time of Serbia’s succession to the treaty and not at the time of Kosovo’s accession and the other parties could have objected to it.Footnote 63 In this case, it was not possible for other parties to a treaty, nor Kosovo, to object to Serbia’s statement of exclusion because no state can be forced to enter into relations with other states or entities. The targeted state can criticize the move of exclusion on account of political reasons, but it is not the official objection to a reservation.Footnote 64
Despite the conclusion that both forms of statements of non-recognition are not reservations, and therefore not a treaty instrument as such, they still remain a relevant international legal tool and ‘play a major role in contemporary international relations’Footnote 65 . Precautionary statements are relevant primarily in the realm of politics, having only the indirect relation to international law, mostly relying on the communicative role of international law. Statements of exclusion on the other hand bear direct legal effects which remain in the realm of bilateral relations between an excluding state and a contested entity.
3.2. Objections to accession
Another instrument at the disposal of a state party to a multilateral treaty seeking to challenge the accession of a new party is the institute of objection to accession. Such objections are based on a treaty provision and are included in several conventions concluded under the auspices of the Hague Conference on Private International Law (the HCCH Conventions): the 1961 Apostille Convention (Article 12), the 1993 Convention on Protection of Children and Co-operation in Respect of Intercountry Adoption (Article 44), the 2000 Convention on the International Protection of Adults (Article 54), and the 2019 Convention on the Recognition and Enforcement of Foreign Judgments in Civil or Commercial Matters (Article 29).
Sometimes referred to as the opt-out clause,Footnote 66 this provision aims to allow existing parties to a treaty to file a preventive opposition in order to object to the accession of a new party.Footnote 67 The treaty provision is termed in the following manner:
Any State … may accede to the present Convention …. Such accession shall have effect only as regards the relations between the acceding State and those Contracting States which have not raised an objection to its accession in the six months after the receipt of the notification ….Footnote 68
The inclusion of this clause in multilateral treaties is substantiated by the nature of the relevant conventions. Namely, the HCCH Conventions are considered to be the co-operation conventions,Footnote 69 the prerequisite for co-operation being its acceptance. Pérez-Vera explains that the objection to accession provision is aimed to balance ‘a desire for universality and the belief that a system based on co-operation could work only if there existed amongst the Contracting Parties a sufficient degree of mutual confidence.’Footnote 70 In the case of the 2019 Hague Convention on the Recognition and Enforcement of Foreign Judgments in Civil or Commercial Matters, it was noted that the inclusion of the objection to accession ‘was considered fundamental for some States and consensus to include it was reached with a view to facilitating adherence by individual States and to maximise the reach of the Convention’.Footnote 71
The legal effect of the clause is clearly to hinder the establishment of bilateral relations between an objecting and an acceding party. In that regard, the objection to accession could be considered a form of a statement of exclusion. The main difference between the two is that the objection to accession has a codified procedure that is to be followed upon the accession of a new party, including the deadline for submitting the objection. Another difference that emerges upon closer examination is that while the two unilateral acts produce equivalent legal consequences, it is questionable whether they are supposed to be used for the attainment of the same goals. The statement of exclusion, as understood by the ILC, is closely tied to the non-recognition of an entity towards which the bilateral treaty relations are excluded. On the other hand, the objection to accession has the goal of securing the mutual confidence and co-operation, which can be hindered by issues other than the contested statehood.
In order to unravel the reasons behind the use of the objection to accession in practice, I analysed the objections raised by states regarding the HCCH Conventions listed above. Gaja shortly mentions that objections to accession are generally made with regard to non-recognized states or entities.Footnote 72 However, the analysis shows that while the clause is frequently used in practice by states, the explanation as to why a country objects to accession is an exception rather than the rule.Footnote 73 Also, states submit the objections to accession in relation to states they recognize as well.Footnote 74 Therefore, it is not possible to conclude that the general reason behind the use of the objection to accession is non-recognition. The case of the objection to Kosovo’s accession to the Apostille Convention stands in stark contrast with the prevailing practice of providing no explanation regarding the reasons for using this instrument. In this case, there were more than 30 states that raised objections to Kosovo’s accession, all of whom provided explanations. Almost all of the explanations rested on the contested statehood of Kosovo, with states expressing that they did not recognize Kosovo and/or did not establish bilateral relations with Kosovo, albeit in different terms.Footnote 75
The case of the Kosovo’s accession to the Apostille Convention puts into limelight the position that the objection to accession is not an adequate treaty tool for a state wishing to safeguard its national interest when it does not recognize the statehood of the acceding entity. Both Serbia and Spain have argued that objections to accession are not a valid legal mechanism for non-recognizing states to protect their interests, based on the two related points. The first point is that the objection to accession is of a residual nature to the question of statehood – the objection to accession can be used only after the contested entity’s accession had been filed and accepted by a depositary. The second point is the ineffectiveness of the objection to accession in disputes over the recognition of statehood – objecting to an entity’s accession to a multilateral treaty does not achieve the intended goal of preventing its recognition as a state. These two arguments will be further presented in turn.
As for the residual character of the objection to accession, it rests on the premise that the affirmation of statehood of the acceding entity is a preliminary issue that needs to be set before addressing whether that entity can deposit instrument of accession and the state parties are given the possibility to contest it using the objection to accession.Footnote 76 Serbia and Spain claimed that when the objection to accession provision was triggered, this necessarily implied that the entity was apt to become party to the Convention and the issue of contested statehood was circumvented. Serbia insisted that the Netherlands, as the depositary of the Apostille Convention, circumvented the issue of the contested statehood by filing Serbia’s opposing statementFootnote 77 under the Article 12 objection to accession.Footnote 78 Serbia maintained that the issue of contested statehood needed to be resolved apart from and before resorting to Article 12.
As for the argument of inadequacy of the objection to accession to achieve the goal of protecting a national interest through contesting the statehood of a non-recognized entity, it rests on different purposes of the two instruments. Namely, the objection to accession regards the exclusion of a bilateral legal effect of a multilateral treaty in which co-operation is the prerequisite for implementation of the treaty provisions. On the other hand, the contestation of statehood through a unilateral act under a multilateral treaty does not primarily regard the impossibility of co-operation but the capacity of the contested entity to enter into any legal relations at all. In this case, the impossibility of a cooperation is only a consequence of the root cause of a contested statehood. Therefore, Spain explained that Article 12 was not the adequate means for states to protect their national interest in cases when the contested statehood is at stake. It stated that the accession of Kosovo to the Apostille Convention was ‘a dangerous precedent with unforeseen consequences, harmful for many States’ and that the Article 12 objection was ‘not enough guarantee to avoid the negative consequences on those States Parties having expressly objected’ providing for the hypothetical but probable case when ‘Judicial Decision issued by a Court from a State that could have previously accepted a document apostilled by this territory if such decision should have to be enforced by a State having previously objected’.Footnote 79
In conclusion, the objection to accession as a treaty instrument is not best suited to challenge the statehood of the acceding entity and has in practice seldom been employed for this purpose. The objections of states to Kosovo’s accession to the Apostille Convention are rare examples of using this instrument in order to contest acceeding’s party statehood. While the direct legal effect of the objection to accession amounts to the exclusion of bilateral relations, states strive to achieve an indirect legal effect as well. Namely, states insist on communicating their view on a legal status of a contested entity and on legitimizing their interest not to recognize the statehood of a contested entity in terms through which other states can relate. Despite utilizing the objection to accession for this purpose, states have underscored the importance of distinguishing between the recognition of statehood and the consideration of accession to a treaty, advocating for the resolution of the statehood issues prior to any decision on accession. However, achieving this clear delineation in practice is often challenging, which highlights a significant role played by a depositary of a multilateral treaty. The following part will explore a depositary’s role in instances when states seek to protect their national interests through multilateral treaties.
3.3. The role of a depositary to a multilateral treaty in cases of accession of an entity with the contested statehood
Multilateral treaties have depositaries that are considered to be the ‘administrative hub of the treaty’ and ‘the formal custodian of the treaty’.Footnote 80 According to Article 76 of the VCLT, a depositary may include one or more states, an international organization, or a chief administrative officer of an organization, and its functions are outlined in Article 77 of the VCLT. Of special importance is Article 77 (1)(d) which provides that one of the functions of a depositary is to ‘examin[e] whether the signature or any instrument, notification or communication relating to the treaty is in due and proper form …’. This examination possibly entails a discretionary power of the depositary and states negotiating the VCLT thus wanted to limit this function. They did so through the delineation of the scope of Article 77(1)(d) of the VCLT and by requesting the depositary to act impartially, which is enshrined in Article 76(2) of the VCLT. These two provisions will be presented in turn.
As the examination function ‘raises most delicate issues’, the objective of Article 77(1)(d) of the VCLT was to ‘circumscribe the discretionary power of the depositary’.Footnote 81 This was done by narrowing the scope of examination of the relevant instruments by the depositary. Drafters agree that ‘[t]he depositary examines the formal validity and verify the technical requirements’ and the examination usually does not include substantive matters.Footnote 82 However, the depositary also needs to verify ‘whether a State or international organization is entitled to become a party under the terms of the treaty and it may face questions related to the statehood of certain entities’Footnote 83 which would represent a decision on a substantive matter – a decision on recognition that is not in the competence of the depositary.Footnote 84 It has been well-established that ‘it is for each party to a multilateral treaty to determine the existence of a new State through recognition, an eminently political act which belongs to its discretionary and sovereign interpretation’.Footnote 85 Therefore, the formalistic approach to the scope of the examination reflects the caution of states towards the (pro)active role of a depositary in matters that are reserved for states’ decision-making, such as the recognition of states.
Another, more general way in which states protected their competences with regard to a depositary, was by introducing the obligation of the depositary to act impartially in its performance.Footnote 86 The impartiality of a depositary is understood as a request that the depositary: ‘distinguish strictly between its own views and interests as a State or international organization and its role as a depositary, especially when the depositary is a party … to the treaty’.Footnote 87 This is of special importance in cases of the contested statehood when actions of a state regarding the (non)recognition in its official capacity and in its capacity as a depositary need to be strictly separated. In the context of former Yugoslavia, the impartiality of the depositary became a concern regarding the Federal Republic of Yugoslavia’s (FRY) participation in multilateral treaties deposited with the UN Secretary-General. Due to the ambiguous UN membership status of the FRY and (unsupported) claim to continuity with the Socialist Federal Republic of Yugoslavia, the Secretary-General faced uncertainty about the FRY’s legal standing in these treaties. The Secretary-General adhered to the view that, as the depositary, it ‘was not in a position … either to reject or to disregard the claim of Yugoslavia that it continued the legal personality of the former Yugoslavia’.Footnote 88 Consequently, treaty actions taken by the FRY were listed under the name ‘Yugoslavia’.Footnote 89
In practice, actions of a depositary regarding the assessment of an instrument of ratification of the contested entity can provoke discontent of certain parties to a treaty. Such difference arose between the Netherlands, the depositary of the 1907 Hague Convention and the 1961 Apostille Convention, and several states that did not recognize Kosovo’s independence at the time its instrument of accession to these two conventions was deposited. Regarding the 1907 Hague Convention, Georgia and Spain raised objections; regarding the Apostille Convention, Argentina, Azerbaijan, Belarus, China, Cyprus, Georgia, Serbia, and Spain raised objections.Footnote 90 These states claimed that the Netherlands did not act impartially and that it violated its role as the depositary. The argumentation of the states varied, including the contestation of the action of the Netherlands or suggesting the orderly way to act. Some states contested the agency of the Netherlands that could be construed as direct or implied qualification of entities as statesFootnote 91 ; others vaguely expressed their concern.Footnote 92 Spain qualified actions of the depositary as contravening the required impartiality ‘by acting simultaneously as a State that has recognized this controversial territory’ and in that way encroaching on its technical duties.Footnote 93 Some states proposed that there was a duty of the depositary not to receive the instrument of ratification of the Kosovo authorities.Footnote 94
In a situation when a difference between a state party to a multilateral treaty and a depositary of the treaty regarding the performance of the depositary’s function emerges, Article 77(2) of the VCLT provides that ‘the depositary shall bring the question to the attention of the signatory States and the contracting States or, where appropriate, of the competent organ of the international organization concerned’. However, the concrete actions stemming from this request could prove controversial, as the practice that will be presented below shows.
In the case of accession of Kosovo to the Apostille Convention, Serbia insisted that the issue be brought to the attention of the state parties to the Convention. The Netherlands only informed the treaty parties about the accession of Kosovo and about the Serbia’s protest (which it filed under the Article 12 objection to accession). Serbia expressed the position that: ‘Bringing the matter to the attention of all Contracting States to the Convention concerned … presumes that the Contracting States must be asked for their respective positions concerning the matter of difference.’Footnote 95 There is a difference between the two possible actions – ‘informing on the matter’ and ‘requesting the position’ of the signatory states. According to Serbia, only the latter can be an ‘effective way to bring the matter of difference to the attention of all Contracting States’ especially because ‘in the absence of any decision adopted by the Contracting States … on the controversial question of Kosovo’s statehood, it seems that the exclusive position of the Depositary State to that highly political issue is decisive’.Footnote 96
The discrepancy between the Netherlands’ action and Serbia’s expectations are the result of the non-existent procedure for ‘bringing the matter to attention’ in the VCLT. Villiger notes that Article 77(2) of the VCLT ‘makes no mention of the procedure; the means chosen—consultations, negotiations etc.—may be informal’. Therefore, Serbia and Spain proposed practical steps to be taken by the depositary: they proposed that the deposition of instrument of accession was suspended until the proper decision of the organs of the Hague Conference is reachedFootnote 97 and Spain added the request to the depositary to convene a meeting of all contracting parties.Footnote 98
The relevant organ under the Apostille Convention that Serbia and Spain targeted was the Council on General Affairs and Policy of the Hague Conference on Private International Law (the Council). The Council did discuss the matter and in its ‘Conclusions and Recommendations’ in March 2016 reiterated that the matter should be brought to the attention of all contracting states to the Convention concerned.Footnote 99 Unfortunately, this advice was not very telling for the resolution of the dispute as it did not clarify the procedure for bringing the matter to the attention of state parties.
Other cases in which Serbia and Spain requested a depositary to turn to the relevant organs of a multilateral convention are pertinent to accession of Kosovo to the 1907 Hague Convention and the Convention Establishing a Customs Co-operation Council. In the first case, the relevant body – the Administrative Council of the Permanent Court of Arbitration – convened to reflect on the matter. The meeting was, however, convened on the request of Serbia, and not the depositary and the final decision was adverse to the interest of Serbia and Spain.Footnote 100 In the second case, Belgium as the depositary brought the matter to the attention of the Customs Co-Operation Council in 2012.Footnote 101 After a lengthy discussion, the Council concluded
that it was not mature for the WCO [World Customs Organization] to respond to the Ministry’s request for advice at this point in time. … this matter should not appear on the Policy Commission or Council Agenda again until there was tangible progress, or some other specific reason that warranted its being taken up again.Footnote 102
The matter did not appear on the agenda again, but Kosovo deposited its instrument of accession again in January 2017, eliciting objections by several states, both with regard to the statehood of Kosovo and the role of the depositary.Footnote 103 These objections however did not hinder Kosovo from becoming a party to the Convention on the date of the deposition of instrument of accession in accordance with Article XVIII(c) of the Convention Establishing a Customs Co-operation Council.
As for the Spain’s request to the Netherlands as the depositary to convene the meeting of all parties to the Apostille Convention, the Netherlands stated that convening such a meeting is not one of the functions of the depositary according to the VCLT and it suggested that the ‘Spain Embassy directs its request to convene a meeting of the Contracting States to the Secretary General of the Permanent Bureau of the Hague Conference on Private International Law’.Footnote 104
These instances of disagreements between states parties to a treaty and a depositary in cases of a contested statehood clearly indicate the tension that arises between an impartial and a technical role of the depositary on one hand, and practical legal effects of its actions on the other. The Netherlands claimed that it acted impartially in a formal and technical role, which was reduced to accepting and transmitting the instrument of Kosovo’s accession without entering into the substance of its contested statehood. The legal effect of such an action was, however, the same as it would have been had the Netherlands exceeded its competence and substantially assessed the statehood of Kosovo in its favour. By insisting on a technical role of a depositary as the basis for the impartiality, the thorny issue of statehood might be circumvented but the legal implications of the actions of the depositary regarding the accession of the contested entity are not. This was reiterated and well put by Spain:
Neither the Depositary State could rely on the allegedly neutrality of the ceremony to accept the deposition, because this in fact implies the adoption of a clear position on a political and controverted issue that exceeds its duties as Depositary State.Footnote 105
The potential clash between the impartiality of a depositary and legal effects of its (in)action in cases of contested statehood does not imply that the depositary, particularly if it represents a single state, should shoulder the responsibility of evaluating or making the ultimate decision on disputed statehood claims. This fact rather underscores the significance of the procedure for resolving disagreements between state parties and a depositary, emphasizing that the obligation to ‘bring the matter to the attention of state parties’ must extend beyond mere notification. Ultimately, it is the state parties themselves which should determine the recognition of the entity, because in the absence of such a determination, the contested entity’s accession to a treaty effectively produces certain legal effects to non-recognizing parties as well. It is therefore advisable for future treaties to clearly and in advance define how disputes between state parties and a depositary will be resolved.
3.4. Territorial application of a treaty
Finally, another tool that Serbia used in its quest to protect the national interest towards Kosovo was the territorial application of a treaty. Namely, when the endeavours to hinder Kosovo’s accession to the Apostille Convention proved futile, Serbia turned to Article 13 of the Convention which provided that ‘Any State may … declare that the present Convention shall extend to all the territories for the international relations of which it is responsible, or to one or more of them.’ This provision is the colonial clause. It was inserted in treaties at the time when a clear distinction could have been made between the territories where state had sovereignty (metropolitan territories) and territories that were under someone else’s sovereignty (dependencies). Colonies, where the name of the clause comes from, are the prime example. However, in history, as well as today, there are other relations of dependency between the metropolitan territory and its dependencies, usually expressed in the moniker ‘overseas territories’. Therefore, the colonial clause remains relevant beyond traditional colonial relations and continues to be utilized today.
The European Convention on Human Rights contains a colonial clause in Article 56, which was included in the Convention at the insistence of the United Kingdom (UK)Footnote 106 which still uses the clause today.Footnote 107 Even when treaties do not explicitly include the colonial clause, the UK’s practice in multilateral treaties is to clearly specify the territorial application, including whether it extends to the Crown Dependencies and Overseas Territories.Footnote 108 The UK has detailed regulations on this matter.Footnote 109 When the UK does extend treaties to its dependent territories, the UK’s notification is often met with a response from Argentina, objecting to the extension of a treaty to the Malvinas (Falkland) Islands, South Georgia, and South Sandwich Islands, and reaffirming its claim of sovereignty over these areas.Footnote 110 This interaction exemplifies how both the UK and Argentina use treaty mechanisms to safeguard their national interests. However, the practical impact of such actions remains unclear.Footnote 111
Turning back to the HCCH Conventions, several of them contain the colonial clause. However, it should be stated that even in 1980 it was noted that:
Although such situations [when States are responsible for the international relations of other territories] are meant to disappear as a logical consequence of the progressive application of the principle which proclaims the right of peoples to self-determination, the Conference felt it advisable to keep a clause which might yet prove to be useful.Footnote 112
In more recent HCCH Conventions, this clause has not been included.
Being adopted in 1961, it does not come as a surprise that the Apostille Convention contained the colonial clause, and several states relied on it to define relations with dependent territories.Footnote 113 Serbia reached for the colonial clause as well. On 29 May 2017, Serbia adopted the following statement based on Article 13:
The Embassy of the Republic of Serbia to the Kingdom of the Netherlands … recalling the UN Security Council Resolution 1244 (1999), has the honour to notify esteemed Ministry that the present extension ratione loci of the applicability of the 1961 [Apostille Convention] to the territory of the Serbia’s Province of Kosovo and Metohija has to be interpreted in accordance with Article 13 of the Apostille Convention. Footnote 114
Kosovo objected to such declaration, and claimed that it represents ‘the violation of the sovereignty of the Republic of Kosovo and an attempt to issue falsified documents by … illegal and unauthorized structures [illegal structures of the Government of Serbia or the Government of Serbia]’.Footnote 115 Kosovo called on ‘all Contracting Parties to reject the declaration and asks them to be vigilant in ensuring that they reject any efforts by Serbia to illegally exercise Apostille Convention obligations in the territory of the Republic of Kosovo’.Footnote 116 States that reacted and proclaimed that the declaration of Serbia will not have any legal effect include Austria, France, Germany, Switzerland, and the US.Footnote 117 Moreover, such action of Serbia was not registered by the depositary under the Article 13 territorial extensions but under declarations.Footnote 118
This instance represents an ineffective attempt to use treaty law instruments in protection of a state’s national interest. The colonial clause is rooted in an old and outdated system of international relations and should be approached with caution. Furthermore, in this specific case, relying on the colonial clause fails to accurately depict Serbia’s desired relationship with Kosovo and its national interest in maintaining Kosovo as part of its territory. Therefore, this case indicates that certain international law instruments should not be used at all costs even when they are available. In order to achieve its rhetorical and justificatory function, international law needs to be used prudently.
4. Conclusion
The objective of this research was to examine how international treaty law can be strategically used by non-recognizing states to manage their relations with entities whose statehood they contest. It explored the communicative and legitimizing roles of international law in safeguarding national interests under a multilateral treaty framework. The study applied this theoretical framework to the case of Serbia and Kosovo’s common participation in multilateral treaties, analysing how Serbia, as a non-recognizing state, has used various treaty law instruments to contest Kosovo’s statehood. These instruments include statements of non-recognition (with a particular emphasis on statements of exclusion), objections to accession, engagement with a treaty depositary, and determination of the territorial application of a treaty through the colonial clause.
The findings demonstrate that not all of these instruments hold the same practical value in protecting a state’s national interest in cases of the contested statehood. Among them, statements of exclusion are the most legally effective, as they directly prevent the establishment of bilateral treaty relations under a multilateral framework. While they do not resolve broader questions of statehood, they hold significance for safeguarding national interests within a narrower scope, concerning bilateral relations with the contested entity. This practice is well-established in international law, as evidenced by the consistent use of the exclusion statements by the US and Israel in relation to Palestine’s treaty participation.Footnote 119 The older state practice, such as the 1983 notifications by the United Arab Emirates and Syria upon their accession to the Additional Protocol I to the Geneva Conventions regarding the non-establishment of bilateral relations between these countries and Israel, further illustrate practical utility of this mechanism.
Conversely, other treaty instruments, such as objections to accession, engagement with a treaty depositary and territorial clauses, fall short of providing an adequate ‘direct’ protection for a state’s interests in contesting the statehood of an entity. This underscores the inherently political nature of the statehood recognition and the fact that multilateral treaties are not the primary forum for determining or contesting statehood. Nonetheless, the research emphasized ‘indirect’ effects of using these instruments – to reaffirm the positions of states on contested statehood, to justify their stance within the international legal order in a manner transcending individual interests and relatable to other states, and to clearly signal their positions to other states.
Despite different practical value of various treaty instruments, Serbia’s approach stands out for its comprehensive and multi-instrumental strategy. Unlike other states that rely primarily on statements of non-recognition and exclusion, Serbia has systematically employed all available treaty law mechanisms to challenge Kosovo’s participation in multilateral treaties. In contrast, most states rarely invoke objections to accession as a means of contesting statehood, nor do they actively seek to influence the role of treaty depositaries. A rare comparable case is Morocco’s challenge to the Switzerland’s neutrality as the depositary of the Additional Protocol I to the Geneva Conventions regarding a unilateral declaration by the Front Polisario.Footnote 120 Additionally, disputes over territorial treaty application, such as those between the UK and Argentina, often generate diplomatic friction but rarely lead to significant legal consequences.
In assessing the practical implications of this study, it is essential to recognize both the limitations and possibilities of international treaty law in managing contested statehood under a multilateral treaty framework. While multilateral treaties provide legal mechanisms for states to navigate complex statehood disputes, they do not serve as determinative forums for resolution of these disputes. The unilateral nature of consent in treaty law implies that contested entities retain the ability to engage in multilateral treaties, and non-recognizing states cannot prevent their accession. Moreover, a contesting state cannot hinder unilateral acts of other states with regard to a non-recognized entity and cannot affect the regulation of the contested entity’s relations with the other states. However, through precautionary statements and statements of exclusion, contesting states can limit legal effects of such participation and reaffirm their position within the international legal order.
Ultimately, this research highlights that international treaty law functions not only as a regulatory framework but also as a strategic tool in international relations. Through legal instruments, states engage in a broader process of communication and justification, using treaty mechanisms to shape narratives, align their national interests with legal norms, and influence the behavior of other international actors. This reinforces the notion that international law operates as both a system of rules and a language of international relations, providing a common, predictable and coherent framework for co-operation between states and entities in international arena despite their conflicting interests.
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