Edited by Jürgen Basedow, Giesela Rühl, Franco Ferrari and Pedro de Miguel Asensio
Chapter T.7: Treaties in private international law
It is fair to say that, until the 1950s, treaties in private international law were quite exceptional. Private international law was traditionally regulated by domestic, autonomous conflict rules, either developed by courts or codified in normative instruments (see, for instance, Erik Jayme, ‘Internationalprivatrechtliche, staatsrechtliche, völkerrechtliche Aspekte – 14. Tagung der Deutschen Gesellschaft für Völkerrecht in Göttingen am 10. und 11. April 1975’ in Erik Jayme and Karl M Meessen, Staatsverträge zum Internationalen Privatrecht (CF Müller 1975) 7, 9). In the past decades, however, there has been a notable tendency for states to replace their unilateral sources in this area with a network of treaties in the different sectors of private international law.
According to the Vienna Convention on the Law of Treaties (Vienna Convention on the Law of Treaties of 23 May 1969, 1155 UNTS 331), a treaty is ‘an international agreement concluded between states in written form and governed by international law, whether embodied in a single instrument or in two or more related instruments and whatever its particular designation’. The key elements that characterize a particular instrument as a treaty are its international character, a wide variety of forms that reflect the flexible nature of international law (the instrument’s title is not a determinative factor – treaty, convention, protocol, covenant, charter, statute, act, declaration, concordat, exchange of notes, agreed minute, memorandum of agreement, modus vivendi or any other appellation) and its adherence to international p. 1744law. While the Vienna Convention on the Law of Treaties explicitly refers to states as the subjects of treaties, other subjects of international law, such as a Regional Economic Integration Organization, contract with each other or with states by means of treaties (United Nations, Yearbook of the International Law Commission 1962, vol 2 (United Nations Publication 1964, Sales No 62. V 5) 161; see also Ian Brownlie, Principles of Public International Law (6th edn, OUP 2003) 580; Anthony Aust, Modern Treaty Law and Practice (2nd edn, CUP 2007) 16).
According to art 38(1)(a) of the ICJ Statute (Statute of the International Court of Justice of 26 June 1945, 15 UNTS 355), conventions (or treaties as described above) are one of the main sources of public international law, besides international custom and general principles of law recognized by civilized nations. The reference to ‘public international law’ in art 38(1) of the ICJ Statute is not to be understood as separate from or excluding private international law as, in this context, private international law is a sub-category of public international law.
II. Why treaties to regulate private international law?
The particular objective of private international law, ie the regulation of the interests of citizens in situations connected with more than one state, is adequately served by treaties as these arrangements are meant to be uniformly applied in more than one state (Hans van Loon, ‘Unification and Co-operation in Family Law’ in Alegría Borrás and others (eds), E Pluribus Unum. Liber Amicorum Georges A L Droz. On the Progressive Unification of Private International Law. Sur L’Unification Progressive du Droit International Privé (Martinus Nijhoff 1996) 175). For instance, in the particular area of civil procedure, a state may provide for recognition of foreign judgments or foreign official documents, but it cannot ensure the recognition by other states of its own judgments and official documents. To reach such a goal, international cooperation is needed, either by entering into an arrangement with one given party, leading to a bilateral treaty, or between three or more parties (a multilateral treaty). More generally, addressing the issues arising from different legal rules applicable to cross-border situations (with regard to either international civil procedure and/or the conflict of laws) at the international plane is beneficial in terms of increased predictability and legal certainty for citizens involved in international situations. A treaty which contains provisions relating to the different areas of private international law – ie provisions on the governing law, provisions regarding the determination of international jurisdiction, provisions regarding the recognition and enforcement of judgments as well as provisions on cross-border cooperation between relevant authorities to ensure a proper application of the treaty itself – ensure a very high level of legal certainty for citizens facing legal diversity (Mattijs Herbert Van Hoogstraten, ‘La codification par traités en droit international privé dans le cadre de la Conférence de la Haye’ (1967) 122 Rec. des Cours 337). The Hague Child Protection Convention (Hague Convention of 19 October 1996 on jurisdiction, applicable law, recognition, enforcement and co-operation in respect of parental responsibility and measures for the protection of children, 35 ILM 1391) is one such example of a comprehensive treaty which improves the cross-border protection of children by addressing a variety of private international law issues.
At the same time, treaties are only one category of public international law sources which may regulate private international legal issues. States or other subjects of international law may also revert to alternative mechanisms in order to develop uniform private international law.
The past decades have indeed been characterized by a proliferation of non-binding instruments in the area of private international law, such as model laws, legislative guides, principles etc. Such instruments do not involve the creation of per se legally binding norms, yet they still contribute to the unification of private international law. In other words, they share the same objective as treaties in private international law but they are different as to their formation or binding nature. Their greater degree of adaptability to the domestic systems of private international law are essential advantages when states or other subjects of international law pursue the development of unified international standards. Conversely, states or other subjects of international law cannot become party to an instrument which is developed as a non-binding standard. They can instead consider such an instrument as a model for the development or reform of their domestic legislation. The prevailing view appears to indicate that a non-binding instrument cannot be given the status of a treaty in the sense of the Vienna Convention on the p. 1745Law of Treaties because the reference to a treaty as a norm which is ‘governed by international law’ (art 2(1)(a) Vienna Convention on the Law of Treaties) presupposes that such norm is capable of creating obligations under international law (Anthony Aust, Modern Treaty Law and Practice (2nd edn, CUP 2007) 20). Accordingly, instruments developed in the framework of international professional and/or academic groupings such as the International Law Association or the International Law Institute cannot be considered to be treaties in private international law, even though they serve the same goal of approximation or unification of the rules in this area. Examples of such instruments are inter alia the CLIP Principles (European Max Planck Group on Conflict of Laws in Intellectual Property, Conflict of Laws in Intellectual Property: The CLIP Principles and Commentary, OUP 2013) and several influential ILA or ILI Resolutions relating to key aspects of private international law (to refer to some recent ones, Resolution No 1/2000 of the ILA on Declining and Referring Jurisdiction in Civil or Commercial Matters, available at www.ila-hq.org; or the ILI 1995 Resolution on Cooperation between State Authorities Combating the Unlawful Displacement of Children, available at <www.justitiaetpace.org>). Similarly, the development of such instruments within intergovernmental organizations such as the →Hague Conference on Private International Law or the International Institute for the Unification of Private Law (→UNIDROIT) and their adoption pursuant to the rules of procedure of the corresponding intergovernmental organization does not influence their characterization: they are still not to be considered ‘treaties’ (United Nations, Yearbook of the International Law Commission 1962, vol 2 (United Nations Publication 1964, Sales No 62. V 5) 31; Georges Droz, ‘La Conférence de La Haye de droit international privé et les méthodes d’unification du droit: traités internationaux ou lois modèles’  R.D.I.D.C. 511). The Hague Principles on Choice of Law in International Commercial Contracts (approved on 19 March 2015, available at <www.hcch.net>) may constitute the most recent example of a non-binding instrument – and hence not a treaty – in private international law (see, for further details, Permanent Bureau of the Hague Conference on Private International Law, ‘Choice of Law in International Commercial Contracts: Hague Principles?’  Unif.L.Rev. 883–903, in particular at 886 and the bibliography on this instrument available at <www.hcch.net>).
Furthermore, in the specific context of the EU, the relevance of treaties in private international law has notably decreased since the EU gained legislative competences to develop regulations, directives and other instruments of EU law. The Treaty of Amsterdam (Treaty of Amsterdam amending the Treaty on the European Union, the Treaties establishing the European Communities and certain related acts (consolidated version),  OJ C 340/01) is generally considered to be the turning point for this evolution: several fundamental treaties in private international law, which came into existence before 1997, have since been superseded by regulations. For example, the Brussels Convention (Brussels Convention of 27 September 1968 on jurisdiction and the enforcement of judgments in civil and commercial matters,  OJ L 299/32, consolidated version,  OJ C 27/1), being the cornerstone of EU private international law, gave way first to the Brussels I Regulation (Regulation (EC) No 44/2001 of 22 December 2000 on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters,  OJ L 12/1) and subsequently to the Brussels I Regulation (recast) (Regulation (EU) No 1215/2012 of the European Parliament and of the Council of 12 December 2012 on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters (recast),  OJ L 351/1).
At present, EU instruments cover extensive areas of private international law. Furthermore, such instruments operate differently than treaties as the latter may have direct legal effect without being subject to ratification or any other process at the domestic level. The prevalence of EU instruments in the private international law arena has furthermore given rise to interesting legal issues of articulation between treaties and EU instruments (see inter alia Alegría Borrás, ‘Les clauses de déconnexion et le droit international privé communautaire’ in Heinz-Peter Mansel and others (eds), Festschrift für Erik Jayme (Sellier 2004) 51–72; Jan-Jaap Kuipers, ‘The European Union and the Hague Conference on Private International Law: Forced Marriage or Fortunate Partnership?’ in Henri de Waele and Jan-Jaap Kuipers (eds), The European Union’s Emerging International Identity: Views from the Global Arena (Brill Nijhoff 2013) 181–3). In certain cases, treaties contain so-called ‘disconnection p. 1746clauses’ to ensure that EU instruments prevail. Examples of this coordination technique can be found in art 51(4) of the Hague Maintenance Convention 2007 (Hague Convention of 23 November 2007 on the international recovery of child support and other forms of family maintenance,  OJ L 192/51), which ‘gives way’ to the application of the Maintenance Regulation (Council Regulation (EC) No 4/2009 of 18 December 2008 on jurisdiction, applicable law, recognition and enforcement of decisions and cooperation in matters relating to maintenance obligations,  OJ L 7/1), or art 64 of the →Lugano Convention (Lugano Convention of 30 October 2007 on jurisdiction and the recognition and enforcement of judgments in civil and commercial matters,  OJ L 339/3), which gives primacy to the Brussels I Regulation. In other cases, a treaty and an EU instrument apply in a coordinated fashion, for example, by an explicit referral to a treaty in an EU Regulation (for instance, art 15 of the Maintenance Regulation ‘gives way’ to the Hague Maintenance Protocol 2007 (Hague Protocol of 23 November 2007 on the law applicable to maintenance obligations,  OJ L 331/19) in the Member States bound by that instrument). The interaction of a treaty and an EU instrument may also be a matter of careful delimitation of the relevant instruments, such as the interaction between the Hague Child Protection Convention (Hague Convention of 19 October 1996 on jurisdiction, applicable law, recognition, enforcement and co-operation in respect of parental responsibility and measures for the protection of children, 35 ILM 1391), the Hague Child Abduction Convention (Hague Convention of 25 October 1980 on the civil aspects of international child abduction, 1343 UNTS 89) and the Brussels IIa Regulation (Council Regulation (EC) No 2201/2003 of 27 November 2003 concerning jurisdiction and the recognition and enforcement of judgments in matrimonial matters and the matters of parental responsibility, repealing Regulation (EC) No 1347/2000,  OJ L 338/1). The interwoven application of such instruments is further determined pursuant to Opinion 1/13 rendered by the CJEU (→Court of Justice of the European Union) on 14 October 2014 on the competence to accept the accessions to a treaty (in casu the Hague Child Abduction Convention) by states outside the EU (available at <http://curia.europa.eu>). The CJEU, which was requested to decide whether it is for the EU or for the Member States to accept such accessions, ruled in favour of the exclusive competence of the EU. The CJEU’s Opinion reaffirmed its prior case-law on external competence of the EU and, in line with art 3(2) TFEU (The Treaty on the Functioning of the European Union (consolidated version),  OJ C 326/47), confirmed that the EU enjoys exclusive competence where an international treaty affects EU rules or alters their scope. With regard to international →child abduction rules, they are indeed both contained in the Hague Child Abduction Convention and in the Brussels IIa Regulation. Furthermore, according to the CJEU, ‘the scope and effectiveness of the common rules laid down by the regulation are likely to be affected when the Member States individually make separate declarations accepting third-State accessions to the 1980 Hague Convention’. While the legal reasoning followed by the CJEU is open to criticisms (see inter alia Alegría Borrás, ‘La aceptación de las adhesiones al Convenio de La Haya sobre sustracción de menores: el Dictamen del TJUE de 14 de octubre de 2014’ (2014) 21 La Ley Unión Europea 42), the Opinion has to be welcomed as representing the end of an institutional deadlock to the application of a relevant treaty to specific child abduction cases, and thus to children in need. It is now for the EU institutions to speedily take up their responsibilities as regards any newly acceded state and contribute to the best possible operation of this treaty.
While treaties and EU instruments are normally set to coexist, a treaty can be denounced further to the adoption of an EU instrument on the same subject matter. For example, the →Netherlands had ratified the Hague Succession Convention (Hague Convention of 1 August 1989 on the Law Applicable to Succession to the Estates of Deceased Persons, available at <www.hcch.net>) (for the Kingdom in Europe only). However, as an indirect consequence to the entry into force of the Succession Regulation (Regulation (EU) No 650/2012 of the European Parliament and of the Council of 4 July 2012 on jurisdiction, applicable law, recognition and enforcement of decisions and acceptance and enforcement of authentic instruments in matters of succession and on the creation of a European Certificate of Succession,  OJ L 201/107; →Rome IV Regulation), the Netherlands denounced the Convention on 17 December 2014, with effect as per 1 April 2015.
III. p. 1747Treaty techniques in the area of private international law
The process of negotiating, adopting, consenting to and bringing a treaty into effect falls outside the scope of this contribution as these processes are regulated by public international law. It suffices to say that treaties in private international law, like treaties in other branches of international law, are governed by the 1969 Vienna Convention on the law of the treaties more generally.
However, it is interesting to review which treaty techniques are more often used by negotiators in the area of private international law. An overview of some of the most important instruments shows that multilateral treaties concluded in the framework of an intergovernmental organization are generally open to the signature of at least all states that negotiated and concluded the treaty. These multilateral treaties can be ‘open’ to other states so that states which did not conclude the treaty can accede to it without further conditions. An example of such an ‘open’ treaty is the Hague Choice of Court Convention (Hague Convention of 30 June 2005 on choice of court agreements, 44 ILM 1294), which stipulates in art 27 that the Convention is ‘open for signature by all States [and] subject to ratification, acceptance or approval by the signatory States’, as well as ‘open for accession by all States’.
Alternatively, accession to the treaty for non-negotiating states can be subject to conditions, either in the form of an acceptance of accession or in the form of an objection to accession.
In the first case (acceptance of accession or ‘opt-in’ approach), the treaty enters into force between an acceding state and a contracting state if the latter declares acceptance of the former’s accession. An example of such an ‘opt-in’ system can be found in art 39 of the Hague Evidence Convention (Hague Convention of 18 March 1970 on the taking of evidence abroad in civil or commercial matters, 847 UNTS 241), which stipulates that the Hague Evidence Convention will have effect ‘only as regards the relations between the acceding State and such Contracting States as will have declared their acceptance of the accession’.
In the second case (objection to accession or ‘opt-out’ approach), the treaty will only enter into force between the acceding state and those contracting states that have not raised an objection to the accession of that state. The treaty should contain further indications as to how the objection should be raised. For example, art 58 of the Hague Maintenance Convention 2007 allows for a period of 12 months after the date of the accession’s notification by the Convention’s depositary or at the time when states ‘ratify, accept or approve the Convention after an accession’.
Finally, it is rather unusual for a treaty in private international law to follow the ‘veto approach’, ie a system which requires that no contracting state objects to a given state’s accession. Article 29 of the Hague Recognition and Enforcement Convention (Hague Convention of 1 February 1971 on the recognition and enforcement of foreign judgments in civil and commercial matters, 1144 UNTS 258) provides an illustration of this approach as ‘the Convention shall enter into force for such a State in the absence of any objection from a State which has ratified the Convention before such deposit . . .’. The same Hague Recognition and Enforcement Convention provides an example of another restricting technique for the instrument to enter into force, ie a requirement of a supplementary agreement being concluded between two States Parties to the Convention (the ‘bilateralization approach’). Consequently, the Hague Recognition and Enforcement Convention never entered into force, as some anticipated a long time ago (Karl M Meessen, ‘Völkerrechtliche und verfassungsrechtliche Aspekte – 14. Tagung der Deutschen Gesellschaft für Völkerrecht in Göttingen am 10. und 11. April 1975’ in Erik Jayme and Karl M Meessen, Staatsverträge zum Internationalen Privatrecht (CF Müller 1975) 49, 53).
Besides the above-mentioned approaches, most treaties in private international law use reservations and/or declarations to ‘customize’ the legal effect of certain provisions of the treaty in their application in the state that makes the reservation. Reservations are defined in art 2(1)(d) of the Vienna Convention on the Law of Treaties while declarations are not. It is therefore often difficult to make a distinction between a declaration and a reservation, especially when the legal effects of such principally unilateral acts extend, by operation of the reciprocity principle, to other contracting states (Alfred E Von Overbeck, ‘L’application par le juge interne des conventions de droit international privé’  Rec. des Cours 1, 34). Certain Conventions do not permit the operation of reservations at all (see, for instance, art 21 of the Hague p. 1748Securities Convention (Hague Convention of 5 July 2006 on the law applicable to certain rights in respect of securities held with an intermediary, 46 ILM 649)).
Anthony Aust, Modern Treaty Law and Practice (2nd edn, CUP 2007);
Alegría Borrás, ‘La aceptación de las adhesions al Convenio de La Haya sobre sustracción de menores: el Dictamen del TJUE de 14 de octubre de 2014’ (2014) 21 La Ley Unión Europea 42;
Alegría Borrás and others (eds), E Pluribus Unum. Liber Amicorum Georges A L Droz. On the Progressive Unification of Private International Law. Sur L’Unification Progressive du Droit International Privé (Martinus Nijhoff 1996);
Ian Brownlie, Principles of Public International Law (6th edn, OUP 2003);
Erik Jayme, ‘Internationalprivatrechtliche, staatsrechtliche, völkerrechtliche Aspekte – 14. Tagung der Deutschen Gesellschaft für Völkerrecht in Göttingen am 10. und 11. April 1975’ in Erik Jayme and Karl M Meessen, Staatsverträge zum Internationalen Privatrecht (CF Müller 1975) 7;
Karl M Meessen, ‘Völkerrechtliche und verfassungsrechtliche Aspekte – 14. Tagung der Deutschen Gesellschaft für Völkerrecht in Göttingen am 10. und 11. April 1975’ in Erik Jayme and Karl M Meessen, Staatsverträge zum Internationalen Privatrecht (CF Müller 1975) 49;
Antoon VM Struycken, ‘Coordination and Co-operation in Respectful Disagreement: General Course on Private International Law’ (2004) 311 Rec. des Cours 5;
United Nations, ‘Report of the Commission to the General Assembly’ UNGAOR 17th Session, Supp No 9 UN Doc A/5209 (1962), reprinted in  2 Yearbook of the International Law Commission 157, UN Sales No 62. V 5;
Mattijs Herbert Van Hoogstraten, ‘La codification par traités en droit international privé dans le cadre de la Conférence de la Haye’ (1967) 122 Rec. des Cours 337;
Alfred Verdross and Bruno Simma, Universelles Völkerrecht: Theorie und Praxis (3rd edn, Duncker & Humblot 1984);
Alfred E Von Overbeck, ‘L’application par le juge interne des conventions de droit international privé’  Rec. des Cours 1;.