A. Disregarding the Textual Limits of the Treaty under Interpretation

As is the case with any interpretive principle, application of the principle of systemic integration is limited by the explicit language of the treaty under interpretation.Footnote ¹⁹ The weight accorded to provisions from other treaties in the construction of the treaty at issue cannot lead to an interpretation that goes beyond the plain meaning of the treaty's text. There have been cases, however, in which reliance upon other treaties has driven an interpretation that distorts the language of a human rights treaty.

In the Zolotukhin case, the applicant alleged a violation of Article Four of Additional Protocol Seven (Article 4 of AP 7) to the European Convention on Human Rights (ECHR),Footnote ²⁰ complaining that he had been prosecuted twice for the same offence.Footnote ²¹ Article 4 of AP 7 reads:

The Grand Chamber of the ECtHR held that the term ‘offence’ should be understood by reference to the legal classifications under national law. Hence, if an act was classified as constituting two distinct criminal offences under national law, the prohibitions of Article 4 of AP 7 would not apply. The Grand Chamber analysed the definition of the term ‘offence’ by referring to similar provisions in other treaties containing formulations of the ne bis in idem principle. Reference was made to the pertinent provisions of the International Covenant on Civil and Political Rights (ICCPR);Footnote ²² the Statute of the International Criminal Court (ICC Statute);Footnote ²³ the Charter of Fundamental Rights of the European Union (EU Charter);Footnote ²⁴ the Convention Implementing the Schengen Agreement;Footnote ²⁵ and the Inter-American Convention on Human Rights (IACHR).Footnote ²⁶ Article 14(7) ICCPR and Article 50 EU Charter contain the term ‘offence’, Article 8(4) IACHR refers to ‘cause’, Article 54 of the Schengen Agreement mentions ‘acts’ and Article 20(1) ICC Statute refers to ‘conduct’. The Court emphasized that the jurisprudence of the Court of Justice of the European Union (CJEU) and the IACtHR followed the most favourable approach to the applicant and that, for this reason, it could not ‘justify adhering to a more restrictive approach’.Footnote ²⁷ The Grand Chamber unanimously overruled its previous case law and dramatically altered the scope of applicability of Article 4 AP 7.

The driving force behind the Court's reasoning was its construction of the ECHR in light of other treaties and the Court's decision to base its ruling on the jurisprudence of other international courts. The Court's reliance on the jurisprudence of the CJEU and the IACtHR in order to reach the most favourable interpretation for the applicant is ill-founded. This is because the rulings of these two international courts were interpreting the Schengen Agreement and the IACHR, respectively, which frame the ne bis in idem prohibition in broader terms than the ECHR does.Footnote ²⁸ The ECtHR thus relied upon an interpretation of the Schengen Agreement and the IACHR to arrive at a broad definition of the specific, restricted term ‘offence’ contained in Article 4 of AP 7. The Grand Chamber afforded such great weight to these treaties and their interpretation by other courts that it effectively disregarded the textual limits of the ECHR. It is doubtful whether, as has been argued, the judgment in Zolotukhin is a positive example of constructive dialogue among international courts.Footnote ²⁹ In the Mamatkulov and Askarov and Scoppola cases, the Grand Chamber overruled its previous jurisprudence in a similar fashion by disregarding the limitations of the language in the ECHR.Footnote ³⁰

Likewise, the IACtHR in Artavia Murillo et al.—a case concerning in vitro fertilization and the question of whether Article 4 IACHR protects the right to life of an embryo—construed the IACHR in a manner contrary to its letter. Even though Article 4(1) provides that ‘[the right to life] shall be protected by law and, in general, from the moment of conception’, the Court ruled that an embryo cannot be understood to be a person for the purposes of Article 4.Footnote ³¹ In reaching this conclusion, the Court emphasized that trends in international law do not support the position that an embryo should be treated as a person, or that it has a right to life.Footnote ³² The Court conducted its interpretation of the IACHR by referring to other treaties and instruments, as well as the views of human rights bodies,Footnote ³³ including the Universal Declaration on Human Rights;Footnote ³⁴ the Convention on the Elimination of All Forms of Discrimination against Women (CEDAW)Footnote ³⁵ and the views of the CEDAW Committee; the Convention on the Rights of the Child (CRC);Footnote ³⁶ the ICCPR and the views of the Human Rights Committee (HRC) which monitors the implementation of the ICCPR; the African Charter on Human and People's Rights (ACHPR);Footnote ³⁷ and, finally, the ECHR and the case law of the ECtHR. This was, however, an inappropriate application of systemic integration, not only because many of these treaties do not bind the member States to the IACHR,Footnote ³⁸ but also, most importantly, because none of these treaties explicitly protects unborn life. Article 4 IACHR is a unique formulation of the right to life in international human rights law and, hence, it is questionable how far other more general treaties and instruments shed light on its interpretation. The problems in the Court's reasoning can be illustrated by its reference to the Vo. v France case, in which the ECtHR stated that:

Most international human rights treaties are able to accommodate change over time because of their vaguely drafted text, which affords considerable leeway to the interpreter. Yet, the interpreter cannot properly pursue a construction of a treaty that amounts to a revision of its text.Footnote ⁴⁰ In the cases discussed above, the ECtHR and the IACtHR seem to have crossed that line.

B. Duly Appreciating the Contextual Nuances between Different Treaties?

International courts and other international bodies have developed an extensive case law establishing synergies and links between the treaty under their jurisdiction and other treaties. These synergies and links are welcome, and are attuned to the goal of pursuing coherence in international law. Nonetheless, taking account of norms in other treaties that are similar or identical to those in the treaty under interpretation should be subject to pertinent contextual nuances pertaining to the purpose, function and aims of the other treaty provisions.Footnote ⁴¹ In order for the interpreter to ascertain and give due regard to such nuances, he or she needs not only to identify the core of similarity among equivalentFootnote ⁴² treaty provisions but also to appreciate the differences between them. The question is, therefore, whether international courts meaningfully engage with other treaties so as to value the different contexts from which provisions in these treaties originate. It is important that the international judge examines and explains how the other treaty is relevant and, accordingly, how it informs the proper construction of the treaty being interpreted. This section argues that such nuances are easily disregarded.

The Van der Mussele and Siliadin cases exemplify how the ECtHR should give consideration to other treaties while still preserving the particular language and purpose of the ECHR.Footnote ⁴³ In Van der Mussele, the applicant alleged a violation of the prohibition on ‘forced or compulsory labour’ under Article 4(2) ECHR. In its analysis, the Plenary Court referred to both the 1932 International Labour Organization (ILO) Convention Concerning Forced or Compulsory Labour (ILO Convention No 29)Footnote ⁴⁴ and the 1959 ILO Convention on the Abolition of Forced Labour.Footnote ⁴⁵ The definition of ‘forced or compulsory labour’ contained in ILO Convention No 29 and the standards adopted by the ILO Committee of ExpertsFootnote ⁴⁶ informed the Court's construction of Article 4 ECHR. The Court stressed that the ILO Convention would provide the ‘starting point for the interpretation of Article 4’,Footnote ⁴⁷ but that ‘sight should not be lost of [the European] Convention's special features’.Footnote ⁴⁸ The question whether the applicant unwillingly offered his services was not assessed against the ILO approach to the meaning of consent,Footnote ⁴⁹ but rather against the structure and aims of Article 4 ECHR. Hence, the ECtHR neither unqualifiedly relied on, nor did it integrate, ILO Convention No 29. Likewise, in the Siliadin case, the ECtHR recognized the definition in ILO Convention No 29 of ‘forced or compulsory labour’, according to which the work or service must be extracted from an individual under the menace of penalty. Although the applicant in the circumstances of the case had not been threatened by a penalty, the Court found that she was in an equivalent situation due to her vulnerable position.Footnote ⁵⁰ In this way, the Court, in light of the specific facts, equated the ILO standard of being threatened by a menace of penalty to perceiving to be threatened by a penalty.

In contrast, in other instances the ECtHR has drawn interpretive guidance from other treaties while ignoring contextual differences, uncritically transposing the detailed standards of other treaties into the provisions of the ECHR. In the National Union of Rail, Maritime and Transport Workers case, the Court held that the Convention protects sympathy strikes. It referred to a series of international treaties and views of international bodies in its legal reasoning, but it failed to examine exactly how the norms of these treaties were relevant or how they aided in the interpretation of Article 11 ECHR.Footnote ⁵¹ The Court stressed that the ILO Committee of Experts and the ILO Committee on Freedom of Association had supported the position that a general prohibition on sympathy strikes violates the right to strike, even though these bodies simply mentioned that a general ban could lead to abuse in light of the specific circumstances.Footnote ⁵² Further, the restrictions on the right to strike in the EU Charter were not sufficiently addressed. Finally, the Court relied heavily upon Article 6 of the European Social Charter (ESC),Footnote ⁵³ without acknowledging that most of Article 6's undertakings are optional and that ten European States have chosen not to guarantee the right to strike under the ESC.

The expansive interpretation of the ECHR given in the National Union of Rail, Maritime and Transport Workers case follows the Court's approach in the area of socio-economic rights. In Demir and Baykara, the Grand Chamber accepted that the right of public officials to form and join a trade union and to bargain collectively has become one of the essential elements of Article 11 ECHR.Footnote ⁵⁴ This judgment also paved the way for recognizing the right to strike and the right to collective action under Article 11.Footnote ⁵⁵ The legal reasoning in both National Union of Rail, Maritime and Transport Workers and Demir and Baykara was grounded in the consideration of ILO Conventions and the ESC and their progressive development by their respective monitoring bodies. The judgments share the same methodology: namely, discerning an alleged analytical common denominator by reference to a great variety of treaties. One could argue that this so-called integrated approach to the interpretation of the ECHR seeks to integrate socio-economic rights into individual and political rights, and that it is founded upon the ideas of cross-fertilization between and convergence among different treaties.Footnote ⁵⁶ Yet cross-fertilization and convergence of treaty norms cannot justify transplanting detailed provisions of other treaties into the scope of the ECHR without considering the relevant context of the other treaties.

Another example demonstrating how the ECtHR pursues systemic integration by ignoring crucial contextual differences is the Opuz case. Because, under certain Turkish legislation, perpetrators of domestic violence could not be prosecuted if the victim withdrew her complaint, the applicant claimed a breach of Article 2 ECHR due to the legislation's lack of a deterrent effect. Despite the clear absence of consensus among Member States on this matter, the Court ruled that States have a positive obligation under the ECHR to establish and effectively apply a system punishing all forms of domestic violence, and to provide sufficient safeguards for victims.Footnote ⁵⁷ This conclusion was reached by invoking the standard of due diligence as a yardstick for assessing State responsibility in the context of violence against women.Footnote ⁵⁸ In the process of finding an analytical common denominator between the ECHR and a series of other treaties, the ECtHR made the mistake of detaching the different variants of the due diligence standard from the contexts of these other treaties. More specifically, the Court drew upon General Recommendation 19 issued by the CEDAW Committee and the Committee's views as expressed in individual communications, including its views as stated in the A.T. v Hungary case.Footnote ⁵⁹ A careful reading of A.T. reveals, however, that the CEDAW Committee did not explicitly mention a failure to exercise due diligence.Footnote ⁶⁰ The ECtHR in Opuz devoted special attention to the Inter-American Convention on the Prevention, Punishment and Eradication of Violence against Women (Belem Convention), which was the only treaty in force (at the time) addressing violence against women,Footnote ⁶¹ and the related practice of the Inter-American Commission on Human Rights (IACmHR). In the Maria Da Penha v Brazil case, the IACmHR held that States must exercise due diligence by deterring and investigating domestic violence incidents.Footnote ⁶² The ECtHR, however, did not acknowledge that the IACmHR employed the due diligence standard in Maria Da Penha v Brazil by asserting jurisdiction over and applying the specialized Belem Convention (and not the IACHR).Footnote ⁶³

In Lohe Issa Konate v Burkina Faso, the question before the ACtHPR was whether the harsh criminal penalties levied by Burkina Faso against the applicant for defamation represented a disproportionate interference with his right to freedom of expression under the ACHPR.Footnote ⁶⁴ A specific feature of the right to freedom of expression under ACHPR and other rights contained in the ACHPR, is that they are subject to so-called clawback clauses.Footnote ⁶⁵ For example, Article 9(2) provides: ‘Every individual shall have the right to express and disseminate his opinions within the law’ (emphasis added). The idea behind subjecting the right of freedom of expression to the limits of domestic law is to preserve the rights of Member States. The Court, however, held that the phrase ‘within the law’ must be interpreted with reference to international standards.Footnote ⁶⁶ It based its reasoning on its consideration of Article 19 ICCPR, the views of the HRC and the practice of the African Commission on Human and Peoples’ Rights (ACmHPR).Footnote ⁶⁷ Although this is, in principle, a welcome development in the context of a growing convergence among international courts when interpreting limitation and clawback clauses,Footnote ⁶⁸ it is not entirely clear to what extent other treaties may be used in this process of interpretation. The ICCPR, the IACHR and the ECHR do not contain similar clauses and, therefore, one might question whether they can be used to ‘neutralize’ these clauses in the ACHPR. In fact, the only other human rights treaty which includes clawback clauses applicable to many of the rights specified in the ACHPR is the Revised Arab Charter,Footnote ⁶⁹ but the ACtHPR made no mention of it. The vice president of the Court, in a separate opinion issued in another case, pointed out this problematic issue, but concluded, with no further explanation, that the ACHPR should be interpreted in the same spirit as the ICCPR.Footnote ⁷⁰

Typically, the IACtHR does not discuss contextual differences between treaties. The ECtHR is more mindful of these, although many pertinent issues are still not sufficiently addressed. To summarize, the principle of systemic integration should not be relied on as the legal tool for an unwarranted alignment of a treaty's meaning with the content of other treaties. After all, it is the task of human rights treaties to establish minimum standards for creating a selected catalogue of rights. In many instances, the ECtHR unfortunately follows an ambitious integrative and harmonizing interpretation of the ECHR with regard to other treaties to such an extent that it raises questions about the boundary between interpreting and rewriting the ECHR. The goal of lessening fragmentation does not justify an excessive striving for uniformity. International courts can and should articulate different approaches and interpretations among treaties, if such articulations are dictated by different treaty contexts.Footnote ⁷¹ The ECtHR's great receptiveness to other treaties is, however, not always accompanied by a rigorous examination of how these treaties are relevant to the ECHR.

Other international bodies pursue a more robust analysis of whether a rule of international law is relevant to the treaty under interpretation. The Appellate Body of the WTO, in the Measures Affecting Trade in Large Civil Aircraft dispute, scrutinized in detail the extent to which other international treaties were related to the issues under dispute.Footnote ⁷² It found that the provisions of the 1992 Agreement between the EU and the USA concerning the application of the 1979 GATT Agreement on Trade in Civil Aircraft were not relevant to determining the meaning of ‘benefit’ under Article 1.1(b) of the Agreement on Subsidies and Countervailing Measures.Footnote ⁷³ The International Court of Justice (ICJ), in the Questions of Mutual Assistance case, accepted that the 1977 Treaty of Friendship and Co-operation Between France and Djibouti had ‘some bearing’Footnote ⁷⁴ on the proper interpretation of the 1986 Convention on Mutual Assistance in Criminal Matters, although it did not elaborate further. The discussions in these cases show that there is room for improvement, which should be the goal of international human rights courts.

C. Indirectly Applying and Supervising Other Treaties

A concern when applying the principle of systemic integration (or Article 31(3)(c) VCLT with the objective of systemic integration) is the risk of conflating the use of a treaty for the purpose of interpretation and the de facto application of that treaty.Footnote ⁷⁵ Systemic integration may lead not only to transposing the detailed standards of one treaty into the scope of a human rights treaty, but also to indirectly applying and supervising these standards under the pretext of interpretation. This, in turn, stretches—if not contravenes—the limited ratione materiae jurisdiction of an international human rights court.Footnote ⁷⁶ As will be discussed, both the IACtHR and the ECtHR tend to discern a common denominator in the various potentially relevant treaties by reading them together and subsequently integrating this denominator into the scope of the IACHR and the ECHR, respectively. The ECtHR articulates this practice mostly in terms of a European consensus; the IACHR explains it in terms of the international corpus juris, positing that a comprehensive and integrative reading of the IACHR alongside other treaties is justified on multiple grounds, including the pro homine principle, Article 29(b) IACHR and Article 31(3)(c) VCLT.Footnote ⁷⁷

The Taşkin and Tătar judgments marked a discernible shift in the ECtHR's interpretation of the ECHR with respect to its willingness to look to potentially relevant environmental protection treaties.Footnote ⁷⁸ This consideration of environment-related norms took the form of fully integrating detailed obligations under the Aarhus Convention relating to access to information, public participation in decision-making and access to justice into the positive obligations of Article 8 ECHR. In effect, the Court provided for indirect environment-related procedural rights and assessed Member States’ acts and omissions against these standards.Footnote ⁷⁹ In a different series of cases concerning children's rights, the principle of systemic integration, Article 31(3) VCLT and the international corpus juris for the protection of children served as the bases for the IACtHR to determine that the content of Article 19 IACHR by incorporating provisions of the CRC.Footnote ⁸⁰ Although the Court stated that the CRC merely sheds light on Article 19 IACHR, the judgment does in fact integrate detailed requirements of the CRC.Footnote ⁸¹

Even more striking is the ECtHR's practice with respect to the Hague Convention on the Civil Aspects of International Child Abduction (Hague Convention).Footnote ⁸² Systemic integration provided the means for the Court to transplant technical provisions of the Hague Convention into Article 8 ECHR. In addition to this, the Court held that any weakening of the Hague Convention's guarantees reduces protections under the ECHR.Footnote ⁸³ The failure of national authorities to meet the six-week requirement to reach a decision on the expeditious return of an abducted child (Article 11 of the Hague Convention), or to diligently enforce this decision, automatically gives rise to a violation of Article 8 ECHR.Footnote ⁸⁴ In this way, the Court effectively supervised the implementation of the Hague Convention under the guise of interpreting the ECHR.Footnote ⁸⁵

International courts have gone so far as to pronounce on Member States’ failures to honour and implement other treaties. In Carlson, Switzerland's actions were ‘not in accordance with Article 11 of the Hague Convention’.Footnote ⁸⁶ In Fornerón and Daughter, the IACtHR found that the fact that Argentina did not specifically criminalize the sale of a child in its domestic law ‘does not satisfy the provisions of Article 35 [CRC]’Footnote ⁸⁷ and is contrary to its obligations under the Optional Protocol of the Convention on the Rights of the Child on the Sale of Children, Child Prosecution and Child Pornography.Footnote ⁸⁸ In Rantsev, the ECtHR found a procedural violation of the right to life because Cyprus had failed to make use of the procedures provided for in a Mutual Legal Assistance Convention.Footnote ⁸⁹ The IACtHR decided that the States’ failure to enact relevant extradition treaties was in violation of their obligations under the right to a fair trial and the right to judicial protection to prosecute and punish those responsible for serious human rights violations.Footnote ⁹⁰ In other words, according to the Court, the IACHR specifically requires Member States to conclude extradition agreements.

Turning to another area of law, in Gonzales Lluy the IACtHR addressed the right to health.Footnote ⁹¹ Notwithstanding the fact that the IACHR does not provide for the right to health and Article 26 IACHR contains only a commitment to progressive development of access to rights rather than a recognition of socio-economic rights,Footnote ⁹² the Court decided to uphold the right to health by linking it to the right to personal integrity and the right to life. In particular, the Court read into the scope of the right to personal integrity the State's obligation to regulate, monitor and supervise the services provided by private healthcare centres.Footnote ⁹³ This link was articulated in light of the interdependence and indivisibility of civil and political rights on the one hand and economic, social and cultural rights on the other—and by taking into consideration a series of international treaties and documents, including the Additional Protocol to the American Convention on Human Rights in the Area of Economic, Social and Cultural Rights,Footnote ⁹⁴ the CRC and the International Covenant on Economic, Social and Cultural Rights (ICESCR).Footnote ⁹⁵ The ICESCR Committee's General Comments articulating a detailed framework for the requirements of availability, accessibility, acceptability and quality of all health services, goods and facilities served as the Court's standard for assessing Ecuador's obligations under the IACHR.Footnote ⁹⁶ The Court was divided, with the point of disagreement among the judges being the scope and nature of Article 26 IACHR and, accordingly, the question of whether the right to health should become justiciable under Article 26 or under the rights to life and personal integrity.Footnote ⁹⁷ The president of the Court submitted an insightful concurring opinion, arguing that, if one were to define the entire content and scope of a right by means of other treaties, this would result in a modification of the IACHR and a delegitimization of the Court.Footnote ⁹⁸ What was not addressed, however, was the question of why these concerns are not equally applicable when detailed soft-law and hard-law standards pertaining to the right to health are fully incorporated into an analysis of the right to personal integrity.

From the cases discussed, it follows that, although both the ECtHR and the IACtHR argue that other treaties and instruments may be used as interpretive references in their reasoning, in practice they have sometimes transplanted external standards into the scope of their constitutive instruments. Specific application of systemic integration has resulted, in many instances, in the indirect application of other treaties under the pretext of interpretation. States may provide different levels of protection for the same rights in different international treaties, or even strategically create divergences or conflicts among treaties.Footnote ⁹⁹ This does not mean that international judges have the competence to resolve such divergences or conflicts, or to align the content of one treaty with another. In some other cases, courts have effectively supervised other treaties.Footnote ¹⁰⁰ This practice stretches their mandate too far and circumvents the consent of States that have not ratified these treaties by imposing on them obligations that they have not assumed. Even when some or all Member States have ratified these treaties, they have not consented to court supervision of their implementation. Establishing the content and meaning of the rights provided for under the ECHR and the IACHR by reading into them not only detailed external obligations, but also arguably new rights, crosses the line between interpreting and modifying human rights treaties.Footnote ¹⁰¹

A. Systemic Integration Is Shaped by Institutional Preferences

Application of the principle of systemic integration does not escape the functional biases and preferences of international courts. This application is affected by the legal and institutional aspects of fragmentation that it purports to overcome in the first place. Interpretation is, therefore, an invaluable yet limited tool for international lawyers and judges.

The debates in the literature usually revolve around the question of whether the introduction of relevant treaties in the process of interpretation could promote, for example, an investment arbitration tribunal or a WTO Panel being receptive to human rights law and, hence, form the basis of a holistic construction over different areas of law.Footnote ¹⁰³ An interesting exercise that demonstrates the intrinsic difficulties involved is to adopt a narrower frame of reference and explore how international courts in the same area of law are restricted not only by the mandate defined by their subject areas (eg human rights, trade) but also by their own judicial policies and preferences. Systemic integration as a policy goal and/or interpretive tool does not necessarily avoid these preferences and biases, nor does it bring coherence to specific areas of public international law—let alone to international law as a whole.

As an example, the IACtHR and the ECtHR are not equally willing to take into account the rights of indigenous peoples when interpreting the IACHR and the ECHR, respectively. The IACtHR has enlarged the scope of Article 21 IACHR by reading into it a collective understanding of the right to property (in accordance with Article 13 of ILO Convention No 169) in the context of the duty of State parties to respect the special relationship that indigenous peoples develop with the lands they occupy or use.Footnote ¹⁰⁴ According to this Court, a comprehensive and integrative reading of the IACHR alongside other treaties is required in order to promote the uniform interpretation of international human rights law.Footnote ¹⁰⁵ This ‘effort of normative integration’Footnote ¹⁰⁶ serves the aim of incorporating the indigenous world view into human rights.Footnote ¹⁰⁷ However, the ECtHR does not share the same degree of sympathy for indigenous peoples’ rights. In the Handölsdalen Sami Village case, the Court did not address how the rights of indigenous peoples and treaties relevant to those rights might inform interpretation of the ECHR.Footnote ¹⁰⁸ This point demonstrates not only the different approaches taken by the courts, but also the selectiveness underlying the application of systemic integration. The IACtHR uses systemic integration and the pro homine principle to construe the corpus juris of international human rights law in favour of serving specific judicial policy goals in the Latin American region.Footnote ¹⁰⁹ Consequently, any claim for a uniform interpretation of human rights or use of integration is subject to (and even reinforces) existing biases and judicial policies. In addition, institutional preferences and structural biases permeate human rights expertise from within, since human rights lawyers may regard themselves as experts in very specific areas (for example, children's or anti-discrimination lawyers) and, therefore, may adopt opposing perspectives and priorities.Footnote ¹¹⁰ These preferences and biases existing at the level of institutions, judicial policy and expertise are entrenched in the practice of human rights law, and, at the very least, one should be aware of them.

B. Prioritizing Concerns beyond Treaty Conflicts?

The principle of systemic integration holds a prominent position in discussions of treaty (or norm) conflicts. Although many scholars have acknowledged that Article 31(3)(c) VCLT is not equipped to resolve true treaty conflicts,Footnote ¹¹¹ the ILC assigns such a role to this provision in its alleged capacity as an expression of the principle of systemic integration. It has additionally been argued that the principle of systemic integration offers the prospect of balancing different values and interests without necessarily predicating or establishing the prevalence of one norm over another.Footnote ¹¹² The interpreter has a role in ‘prioritiz[ing] concerns that are more important at the cost of less important objectives’.Footnote ¹¹³ These claims have not been elaborated on at length, but a few points need to be underlined in light of ongoing judicial practice. First, the task of balancing values or interests is different to prioritizing them; prioritizing is but one option. Second, as will be discussed below, it is doubtful whether the balancing of different interests and values against treaty provisions can be addressed while engaging in interpretation.Footnote ¹¹⁴ Third, it is unclear how one can decide which concerns are most important and prioritize them accordingly; this is an exercise that is dependent on the interpreter's standpoint.

For its part, the IACtHR does not seem inclined to consider, let alone prioritize, interests and values reflected by other treaties unless those interests are perfectly aligned with the aims of the IACHR. To take an example, the Court was firm in its position that a bilateral investment treaty between Paraguay and Germany had no legal bearing on its assessment of whether a series of rights, including the right to property, of the Sawhoyamaxa community had been violated under the IACHR.Footnote ¹¹⁵ In a similar vein, in the Wong Ho Wing v Peru case, the bilateral extradition treaty between Peru and China was largely treated as a fact under domestic law, rather than as an international treaty to be considered in the process of interpreting and applying the right to life under the IACHR.Footnote ¹¹⁶ In other words, the general interest in international cooperation in the specific area of extradition did not have any bearing on the Court's analysis. Finally, in assessing the compatibility of El Salvador's amnesty law with the IACHR, the Court stated that it would take the 1992 Peace Accord and Additional Protocol II to the 1949 Geneva Conventions (AP II) into account.Footnote ¹¹⁷ In this instance, there seemed to be a discrepancy between, on the one hand, the requirement of the AP II to grant the broadest possible amnesties and the need to maintain the negotiated peace,Footnote ¹¹⁸ and, on the other, the Court's inflexible approach in declaring all amnesty laws to be incompatible with the IACHR.Footnote ¹¹⁹ The Court did not enter into this discussion, but simply reiterated its general position—declaring El Salvador's amnesty law to be inconsistent with the guarantees of the IACHR.Footnote ¹²⁰

On the other side of the spectrum, the ECtHR is willing not only to balance external concerns and interests with the guarantees of the ECHR, but even to prioritize the former over the latter. In many instances, the ECtHR has taken other treaties (or the absence of other treaties) into account without proceeding to resolve (or avoid) a conflict of norms. It has on occasion arguably prioritized the admittedly weighty interests expressed in these treaties under international law over the applicability of the ECHR. This has had a significantly restrictive impact on the protective scope of the rights in question. In Carson, the Grand Chamber accepted that the absence of bilateral reciprocal treaties in the social security sphere is a sufficient reason to limit the applicability of Article 14 ECHR; otherwise, Article 14 would effectively undermine the right of States to enter into reciprocal agreements.Footnote ¹²¹ In Waite and Kennedy, the Plenary Court held that the right to access a court should be substantially restricted so as not to undermine the proper functioning of international organizations and international cooperation.Footnote ¹²² In Bosphorus, the Court established the presumption of equivalent or comparable protection between EU law and the ECHR by relying upon the principle of pacta sunt servanda and the need for the proper functioning of international organizations (relating to Ireland's EU membership).Footnote ¹²³

A cluster of cases concerning the Hague Convention on the Civil Aspects of International Child Abduction also illustrates that prioritizing the purposes and goals of other treaties may interfere with the aims, structure and effectiveness of the ECHR. The applicants before the ECtHR claimed that returning the child pursuant to the Hague Convention would be in violation of the best interests of the child and the right to family life under Article 8 ECHR. The Court refused to rigorously review whether the return of the child was in breach of the guarantees of Article 8 ECHR unless there had been an arbitrary decision by national authorities.Footnote ¹²⁴ The crux of these cases involved the fact that Article 13(b) of the Hague Convention provides for an exception to the State parties’ obligation to return a child if there is a grave risk that the child's return would expose him or her to physical or psychological harm or otherwise place the child in an intolerable situation. The Court's previous case law, which applied the Hague Convention's provisions de facto via the ECHR,Footnote ¹²⁵ and the importance attached to preserving the main aim of the Hague Convention (the expeditious return of the child) created the uncomfortable situation in which the Court was obliged to review the requirements of the Hague Convention in light of the ECHR.Footnote ¹²⁶ On the one hand, Article 13(b) of the Hague Convention contains an exceptional ‘escape clause’ pertaining to the return of a child which must be narrowly interpreted, whereas on the other hand, the protection of the best interests and rights of the child serve as primary considerations under Article 8 ECHR (which, in turn, may be subject to restrictions). The ECtHR was hesitant to review the application of the Hague Convention against the guarantees of Article 8 ECHR in light of the risk of undermining the effective implementation of the Hague Convention.Footnote ¹²⁷ The Grand Chamber, in Neulinger and Shuruk, restored this imbalance, ruling that the conditions for the enforcement of the return of the child need to be in strict conformity with Article 8 ECHR.Footnote ¹²⁸

In summary, the IACtHR and the ECtHR have different approaches to other treaties. The IACtHR appears to be fixed in giving little weight to the values and interests of other treaties unless these converge with the aims and implementation of the IACHR. Some scholars have argued that this practice can be rigid and one-sided on certain occasions, especially in the context of amnesty laws. The ECtHR employs the legal methodology of systemic integration in order to justify prioritizing significant interests over the guarantees of the ECHR. The foregoing cases demonstrate that the argument that systemic integration is a means of balancing or even prioritizing among important interests raised by other treaties can lead to significant restrictions on human rights.

C. Exercising Undue Interpretive Authority over Other Treaties

An international court's receptiveness to relevant public international law rules can be a reliable indicator of a reduced risk of diverging interpretations and/or judgments, as well as bolstering cross-fertilization.Footnote ¹²⁹ At the same time, however, an international court's systematic engagement with, and integration of, other treaties raises questions regarding its authority to shape the construction of these treaties. When an international court takes a treaty provision into account for interpretation purposes, it inevitably engages in an articulation of its ordinary meaning.Footnote ¹³⁰ While international courts have the inherent power to construe general international law, they do not have the competence to authoritatively ascertain the ordinary meaning of treaties other than the instruments subject to their jurisdiction.

An exception to this is the jurisdiction that the African Court of Human and Peoples’ Rights enjoys. Article 3(1) of the Protocol establishing the ACtHPR provides that:

Pursuant to this broad jurisdiction, the Court has interpreted, applied and, accordingly, found violations of, for example, the ICCPRFootnote ¹³² and the Economic Community of West African States (ECOWAS) Revised Treaty.Footnote ¹³³ Yet, even in light of the exceptional scope of the ACtHPR's competence, concerns regarding the potential for undue interpretive authority over other treaties are not alleviated. Such concerns relate, obviously, to the risk of divergent interpretations of a treaty which is already supervised by another body. The vice president of the ACtHPR underlined this risk in his separate opinion in the case of Tanganyika Law Society and Legal and Human Rights Centre and Reverend Christopher R. Mtikila v United Republic of Tanzania.Footnote ¹³⁴ However, these concerns are also manifested (and merit equal consideration) in situations in which a treaty is not subject to supervision by an international body or where the interpretation of one of its provisions is contested or unclear.Footnote ¹³⁵ The WTO Appellate BodyFootnote ¹³⁶ and international investment tribunals tend to engage only very reluctantly in the interpretation of other treaties.Footnote ¹³⁷ Human rights courts, however, show no signs of hesitance in this regard.

In the X and others case,Footnote ¹³⁸ the Grand Chamber was divided over the ordinary meaning of the European Convention on the Adoption of Children.Footnote ¹³⁹ Seven dissenting judges strongly opined that the majority's interpretation adhered neither to the letter nor to the object and purpose of Article 7 of this Convention.Footnote ¹⁴⁰ Moreover, the ECtHR regularly defines the ordinary meaning of debated provisions of the Hague Convention on the Civil Aspects of International Child Abduction and corrects the (alleged) shortcomings of national court decisions when applying this Convention.Footnote ¹⁴¹ Judge Pinto De Albuquerque argued that, in the absence of an oversight body for the Hague Convention, the ECtHR should ensure the uniformity of interpretation and implementation of States’ obligations under this Convention.Footnote ¹⁴² The IACtHR, in Artavia Murillo, extensively analysed many human rights treaties, and it is arguable that in the process of doing so adopted an inappropriate interpretation of the CRC and the ICCPR.Footnote ¹⁴³ The Court read and adopted a specific interpretation of the right to life under these treaties that does not necessarily reflect their ordinary meaning or the current views of their supervisory bodies.Footnote ¹⁴⁴ Such instances may be somewhat exceptional (thus far) but they may be indicative of future trends.Footnote ¹⁴⁵ The questions that come to the surface, but are rarely discussed in literature and judicial practice, are the following: Are international courts entitled to have a say in the interpretation of other treaties? If so, what are the implications for the development of international law, and what is the role that these courts assume?

In general, all international courts are equal participants in the development of international law, including general international law (international customary law and general principles of law) and treaties.Footnote ¹⁴⁶ As far as treaties are concerned, international courts frequently refer to and use them as interpretive aids. When doing so, they make sure to approach the authoritative meaning of a treaty provision by relying on how its interpretation has been developed by the treaty's supervisory body. If a treaty lacks a supervisory body, it is the State parties to this treaty that prescribe authoritative interpretations. Yet, it would be unreasonable to question altogether the authority of international courts and bodies to interpret other treaties, should an issue arise when deciding a case that necessitates it. Their interpretations may not be authoritative, but they do enjoy a certain authority.Footnote ¹⁴⁷

The weight of this authority is determined by how an international court ascertains the ordinary meaning of a treaty provision. In the Hague Abduction cases discussed above, the only source that the ECtHR employed as an interpretive aid to support its findings was the 1980 Explanatory Report on the Hague Convention.Footnote ¹⁴⁸ It was only after the Court's use of the Hague Convention was contested that it employed additional and more recent resources to interpret the Convention.Footnote ¹⁴⁹ Although the practice of national authorities (primarily courts) of Member States to the Hague Convention is critical in the sense that it is genuinely authoritative, the ECtHR is not rigorous in identifying and analysing such practice.Footnote ¹⁵⁰ The ECtHR in Monory invoked the practice of European States, although the treaty has been widely ratified on a global level by 94 States,Footnote ¹⁵¹ and the Court essentially cited the practice of one European State! In Neulinger and Shuruk, the ECtHR looked selectively into the practice of certain European and Australian domestic courts.Footnote ¹⁵² Conversely, the weight of the authority of an interpretation by the ECtHR will subsequently be tested against the practice of Member States with respect to the other treaty. This means that, for instance, ECHR Member States can, in theory, disregard the ECtHR's findings as to the interpretation of the Hague Convention; this, however, would put them in a difficult position since they are required to conform to the Court's judgments.

The increasing receptiveness of an international court to relevant treaties, if accompanied by an integrative interpretation, raises questions not only on the level of interpretation but also regarding the role that the court assumes in asserting authority over other treaties.Footnote ¹⁵³ There is the risk of establishing novel, informal hierarchies among international courts on the basis of which exercises the most influential persuasive, interpretive and normative power when construing certain treaties. One cannot fail to note that the discussion over the fragmentation of international law has unfolded as a critique of or in favour of sustaining formal or informal hierarchies among international courts. The perception that the multiplicity of international courts poses a danger to the unity of international law partly reflects the hegemonic conflicts stemming from the ‘loss of hierarchical position by institutions of the ancien régime’Footnote ¹⁵⁴ (referring mostly to the role of the ICJ). In this context, other international courts are not exempt from the same note of caution. Neither the ECtHR nor the IACtHR are immune from the temptation to establish new forms of informal hierarchies.Footnote ¹⁵⁵ It is important to be mindful that shared ownership over international law goes hand in hand with the burden of shared responsibility for its development and for managing international dispute settlement.Footnote ¹⁵⁶ Shared responsibility is not restricted to drafting treaty clauses that regulate overlapping jurisdictions, apply procedural principles or implement judicial comity.Footnote ¹⁵⁷ In the everyday operation of international courts, international lawyers and judges need to be aware of the systemic implications of their judgments in order to avoid exercising undue authority over other treaties. Creativity does not preclude prudence. International courts should conduct more rigorous research on a comparative and international level, and they should enhance the quality of judicial reasoning and methodology, especially when interpreting a treaty that does not fall within their jurisdiction.Footnote ¹⁵⁸

Finally, an argument that is often raised is that certain international courts may present the only viable opportunity to meaningfully develop the reach of a given international treaty which lacks an implementation mechanism. The IACtHR used this reasoning as a basis not only for taking other treaties into account, but also for exercising jurisdiction over the Inter-American Convention to Prevent and Punish Torture,Footnote ¹⁵⁹ despite the fact that it is unclear whether this Convention assigns this task to the Court.Footnote ¹⁶⁰ Although such an argument is somewhat understandable given the shortcomings of the international judicial system, it is tenuous for two reasons.Footnote ¹⁶¹ First, it disregards the pivotal role that domestic courts can play in the interpretation and development of international law and treaties. National courts serve the role of providing accessible justice on a daily basis.Footnote ¹⁶² There is evidence to indicate that domestic courts increasingly engage with questions of international law, employ complex interpretive principles (including systemic integration) and come up with creative decisions.Footnote ¹⁶³ This is not to say that innovative approaches in international litigation are not needed; rather, the point is that we should not wait for domestic remedies to be exhausted in order to pursue international justice.Footnote ¹⁶⁴ We should treat the national judge as an agent of international justice as well. This is all the more pertinent since the national judge is in a unique position to apply the principle of systemic integration without being confined by the limited jurisdiction of an international court.Footnote ¹⁶⁵

The second reason that the systematic and integrative approach of international courts towards other treaties is problematic is its repercussions for their legitimacy and for the overall effectiveness of human rights regime.Footnote ¹⁶⁶ There are growing concerns among Member States to the ECHR regarding the ECtHR's practice of uncritically applying the principle of systemic integration. The lack of transparent legal reasoning and foreseeability in the case law, as well as the States’ unwillingness to transform, de facto, the ECtHR into a supervisory mechanism for their obligations of other treaties, have led to a series of incongruous preliminary objections ratione materiae. Moldova, in Tănase, strongly argued that the Court should not have used the European Convention on NationalityFootnote ¹⁶⁷ as a tool for construing the ECHR, and that the weight attached to this Convention was inappropriate.Footnote ¹⁶⁸ Turkey, in Demir and Baykara, objected to the integration of ILO conventions into the scope of Article 11 ECHR.Footnote ¹⁶⁹ Similarly, the United Kingdom, in National Union of Rail, Maritime and Transport Workers, opposed the interpretive relevance of the legal assessments of the European Committee on Social Rights and the ILO Committee of Experts to the interpretation of Article 11 ECHR.Footnote ¹⁷⁰ From the other side of the Atlantic, Member States to the IACHR have also started to show signs of unease. Paraguay, in the Juvenile Reeducation Institute case, contested the idea that socio-economic rights can be read into the scope of Article 26 IACHR.Footnote ¹⁷¹ In Acevedo Buendía, Peru raised a preliminary objection arguing that an alleged violation of the right to social security falls outside the Court's competence.Footnote ¹⁷² Against this background, the current president of the IACtHR and various scholars caution that the IACtHR's practice of strongly pursuing a pro homine interpretation of the IACHR by applying systemic integration will delegitimize the Court and undermine the progress it has achieved.Footnote ¹⁷³

D. Does the Application of Systemic Integration in the Human Rights Regime Limit the Potential of International Law?

The role that international courts assume in the task of interpretation and their perception of that task are significant to the development of international law. Georges Abi-Saab's metaphor of international law as a parasitic plant that grows erratically by seizing on all opportunities and latching onto anything that offers the possibility of moving towards the lightFootnote ¹⁷⁴ makes one quick to ascribe only weaknesses to the development of international law and to disregard the qualities of diversity and richness encapsulated precisely in the absence of a centralized legislative and judicial authority. International law, despite its sophistication, and its broadening and thickening in recent years, holds more firmly than ever to its old tendency to grow erratically. In their effort to look at international law in an orderly way—with a vision and a goal of bringing together and integrating all the disparate elements of the system into a single coherent story—international courts should be mindful of unintended implications. The uncritical application of the principle of systemic integration, especially in the context of international human rights law, may narrow the existing and potential reach of international law by reducing various concerns and interests to the human rights paradigm.

An exemplary case concerns the integration of environmental norms into the scope of the ECHR, bringing about the long-awaited integration of environmental concerns into human rights discourse.Footnote ¹⁷⁵ This is, in principle, a positive development. Few note, however, the now-prevailing individualistic perspective with regard to environmental protection, and fewer still recognize that the concept of the environment as a public good, indispensable for the life and welfare of society as a whole, is being reduced to a restricted set of individual rights of a procedural character.Footnote ¹⁷⁶ Neither the European nor the Inter-American Courts of Human Rights address an ecological approach to the environment, nor do they appreciate environmental integrity and degradation as issues affecting the community per se.Footnote ¹⁷⁷ This narrow approach has important legal consequences: environmental damage can only be translated into the violation of a human right;Footnote ¹⁷⁸ the victim requirement before international courts is not informed by the collective dimension of environmental integrity; and environmental regulations introduced by States can be assessed only as potential limitations to human rights.Footnote ¹⁷⁹ It could be argued that other regimes and approaches mitigate the shortcomings entrenched in human rights discourse and practice. Yet such an argument disregards the fact that the practice of international human rights courts and bodies is disproportionately influential and, hence, it is highly likely that the ‘narrowest but strongest argument for a human right to the environment’Footnote ¹⁸⁰ will survive and become mainstreamed into the future development of international law, hindering its potential evolution in other directions.Footnote ¹⁸¹

Similar considerations apply to other areas and concerns under international law. It is unclear to what extent human rights treaties—even in light of the integrative and groundbreaking jurisprudence of the IACtHR—are structurally equipped to include and articulate indigenous understandings of ownership.Footnote ¹⁸² It is clear that the IACtHR has not acknowledged indigenous people as a collective group, as rights-holders under the IACHR, but rather as individual members of the community.Footnote ¹⁸³ Neither does the systemic integration approach of the IACtHR give due regard to the potential of the UN Declaration on the Rights of Indigenous Peoples.Footnote ¹⁸⁴ The IACtHR made a choice—one that was never acknowledged—between the ILO Conventions and the UN Declaration, the latter of which sets more demanding standards, more difficult to reconcile with the IACHR.Footnote ¹⁸⁵ Equally concerning is the integration of socio-economic rights into the discourse of civil and political human rights, insofar as we might question whether it is reasonable to expect that the imbalance of power in labour relations and in the complex area of social rights can and should be mediated through the ECHR or the IACHR. In the same vein, the language of human rights is (to some extent) ill-suited to describe how corruption causes harm to socio-economic rights,Footnote ¹⁸⁶ or to acknowledge the effects of systemic discrimination and stigmatization.Footnote ¹⁸⁷ In addition, despite the significant contribution of human rights courts and bodies to recognizing domestic violence as a human rights issue, there are limitations on how far human rights law can go to protect individuals from violations occurring in the private sphere.Footnote ¹⁸⁸ Another topical question is whether international human rights law is capable of articulating and remedying the contemporary refugee crisis.Footnote ¹⁸⁹ And then there is the issue of protecting human rights online. International human rights law is currently attempting to grasp in legal form the concerns pertinent to the digital environment.Footnote ¹⁹⁰ To what extent, however, will the human rights paradigm recognize the complex and distinctive interrelationship between network/national/individual security and online privacy? In the online environment, privacy and aspects of security can be in both a symbiotic and an antithetical relationship,Footnote ¹⁹¹ and privacy can be an important prerequisite for exercising freedom of expression. Nonetheless, according to the structure of human rights law, it is challenging to protect privacy and freedom of expression at the same time; instead, one can only be assessed as a legitimate restriction on the other. How will this dynamic relationship be incorporated into, and inform, legal reasoning and the proportionality test?Footnote ¹⁹²

The foregoing points are not intended to understate the relevance and significance of the human rights approach to other interests and concerns. Pursuing systemic integration within the human rights arena may lead to progressive developments in international law and enrich the human rights discourse while adding value to, and highlighting, new areas of interest. However, one should question whether we should settle for the strongest arguments, which in practice seem to be the easiest arguments to make. Human rights are simultaneously part of the solution and the problem; its well-established and powerful doctrinal and rhetorical vocabulary dominates the imaginative scope of international law and overshadows other possible articulations.Footnote ¹⁹³ In this context, the principle of systemic integration arguably tends to accelerate and intensify this process: the human rights paradigm not only overshadows but also subsumes other emerging areas by ‘squeezing’ them into its own vocabulary, aims, structure and scope. Aspects of these new areas and interests in the law that are not readily reducible to human rights may remain embryonic or fall between the cracks.Footnote ¹⁹⁴ In this sense, international law's store of available words and possible future meanings is being constrained and impoverished.Footnote ¹⁹⁵ Progress and stagnation stand on opposite sides of a very fine line:Footnote ¹⁹⁶ mitigating fragmentation and ensuring consistency should not impede the progressive development of international law in pursuit of more radical and imaginative changes, even if this means that the available narratives become less coherent.

It needs to be underscored that this is a process familiar in many quarters of international law and practice: other areas and regimes may raise similar questions when engaging with other treaties and concerns. It is also true that, in general, human rights law shapes and, in turn, is shaped by other fields and norms in a dynamic, non-linear fashion.Footnote ¹⁹⁷ The present discussion, however, shifts the debate from the conventional focus on interactions among well-known regimes (or the interactions of regimes vis-à-vis general international law) to how the human rights paradigm may develop and/or inhibit the legal articulation of numerous other interests under international law. Applying systemic integration arguably has a unique net effect in the human rights area for a number of reasons: in contrast to other international institutions, human rights courts and bodies are increasingly receptive to the technique of systemic integration;Footnote ¹⁹⁸ as discussed above, human rights possesses a persuasive and appealing discourse that can monopolize our attention; and, finally, judgments by prominent human rights courts are particularly influential and contain the promise of enforcement, especially vis-à-vis norms and treaties that lack monitoring mechanisms.Footnote ¹⁹⁹

To conclude, the consideration and possible incorporation of other interests under international law into human rights and the use of systemic integration in the instances discussed in this article must not become our comfort zone. On the one hand, human rights bodies should acknowledge, engage with and integrate other concerns into their interpretations. On the other, and to the extent that the human rights structure and its conceptual tools fail to accommodate other concerns, we should continue exploring what is legally possible and acceptable for the international legal community.Footnote ²⁰⁰ This could involve forging different norm interactions and synergies or looking into creating different international fora. One way forward could be to move in the direction of setting up more monitoring mechanisms and/or international judicialization. In this way, various interests in international society could be evenly represented and more diverse approaches could be on the table. Yet, even if it is to be assumed that States would give their consent to establishing these mechanisms, international supervision (of a judicial nature or otherwise) in itself does not necessarily guarantee that we will respond effectively to emerging and complex questions. Human rights and international law expertise needs to be both creative in construing the law and mindful of their own limitations.