В настоящей статье предлагается теоретический анализ ключевых подходов к соотношению международного публичного права и национальной правовой системы государств. В ней анализируются ключевые подходы – монистическая и дуалистическая теории. Также обсуждение охватывает концепцию умеренного монизма, которая служит важным теоретическим связующим звеном между классическим и современным подходами к проблеме соотношения правовых систем. Затем в статье рассматриваются более современные теоретические модели, включая глобальный конституционализм и правовой плюрализм. Цель статьи — критически оценить доктринальную согласованность и внутреннюю логику этих подходов, а также обосновать необходимость формирования более интегрированной и гибкой структуры, соответствующей сложности и своеобразию современных правовых систем.
Ключевые слова: международное право, монизм, дуализм, имплементация, правовой плюрализм, конституционализм, нормативная иерархия
Approaches to the correlation of public international law and domestic law
Abstract:This article offers a theoretical analysis of the key approaches to the correlation between public international law and domestic legal system. It examines classical doctrines such as monism and dualism. The discussion then turns to the concept of moderated monism, which serves as an important transitional theoretical link between classical and modern approaches. The article then explores more contemporary theoretical models, including global constitutionalism and legal pluralism. The article aims to critically evaluate the doctrinal coherence and explanatory capacity of these approaches and to argue for a more integrated and flexible framework suitable for the complexity of modern legal orders.
Keywords: monism, dualism, legal pluralism, constitutionalism, normative hierarchy, global norms.
The correlation between international law and the domestic legal system has been a major concern and one of the most enduring and theoretically complex themes of public international law in both classical and contemporary legal scholarship. As international norms increasingly shape domestic policies ranging from human rights, criminal justice, and national security to environmental protection, trade policy, and foreign relation, understanding how these norms integrate into and are incorporated within the domestic law, has become a matter of practical necessity. This correlation between two legal systems, namely public international law and domestic law, is not a simple matter of procedural practice, as well as raising fundamental questions about the nature of the legal system dealing with the states’ sovereignty.
In some countries, international obligations are directly allowed to effect in their domestic legal systems, but other countries apply international obligations only in specific areas, depending on the type and subject of the treaty. In some cases, domestic courts may be unable to interpret some international norms, even such treaties have been formally ratified due to several reasons such as the need for implementing legislation, the absence of self-executing clause or conflict with domestic law. These practical differences show the need for an understanding that can explain how public international law and domestic legal systems interact and what basic principles and norms are necessary for integration of international law to have authority and legitimacy into domestic legal systems.
This study therefore explores a primary research question, namely, what impact do classical and modern approaches to the relationship between international and domestic law have on the incorporation and enforcement of international legal standards within domestic legal systems. As conflicts between international law and domestic legal systems have become increasingly prominent, particularly when national laws or constitutional norms do not fully correspond to the international human rights obligations, it also asks to what extent does giving primacy to international law improve the protection of human rights at the domestic level.
To address these questions, this research systematically examines both classical and modern theoretical approaches to the relationship between international and domestic legal systems, with particular attention to how these frameworks function within the evolving international legal order. Employing a doctrinal and analytical legal research methodology, the study focuses on theoretical models that explain the interaction between public international law and the domestic legal systems in order to develop a theoretical understanding of the correlation between international and domestic legal systems and to evaluate each model in terms of its normative foundations, structural features, and the challenges it faces in the context of modern global legal governance.
While theorists have long debated to explain how international law relates to domestic legal systems, classical doctrine approaches such as monism and dualism provide foundational insights and essential conceptual frameworks for understanding the interaction between international and domestic law. In this view, while monism sees both international law and domestic law as part of a unified legal system, allowing international norms to take effect domestically without the need for additional legislative measures, dualism points out a clear distinction between the two legal systems never cross; each operates independently, and international law does not become part of domestic law unless specifically incorporated through national legislation.[1]. On the other hand, in dualism, international and domestic law are two different legal systems, and formal incorporation of international law through domestic legislation is required so that international law will be effective and legally binding within the domestic legal system.
States apply international law in different ways within their domestic legal systems, which reflects diverse legal practices and raises important theoretical challenges. These differences are not only practical but also reflect important questions about how international law and the domestic legal system relate to each other. Following the experience of the World War I, regarding the conflict between two classical views of monism and dualism, concerning the theoretical approach to the correlation between international law and domestic legal systems, European legal scholars began to seriously examine how and to what extent formal international institutions and binding international legal obligations could reduce the prospects of war.
Even though they are traditional views, those classical legal theories, namely monismanddualism,which are the most notably and frequently discussed in legal doctrine, try to explain the relationship between international law and domestic law. These theories are based on different ideas about how legal authority and norms become valid, and how international legal obligations could be implemented into the domestic legal system.
Understanding these classical approaches is an important step before studying more recent theoretical approaches that aim to reflect the complexity of the contemporary legal order. Hans Kelsen, a leading legal theorist, outlined three core theoretical models for understanding the relationship between international law and domestic law: two versions of monistic theory, which views a single unified legal order with primacy of either international or domestic law, and dualistic theory, which considers international and domestic law as two separate legal systems[2].
Monism is the foundational theory to approach the correlation between international law and the domestic legal system, which forms part of a single system in a unified legal order. According to the monist theory, international law serves as a source of law which is integrated into domestic law, which is not just a legally recommended framework to guide states to relate to each other in the international legal order, but also a binding set of direct applicable and enforceable rules within domestic legal system. In this theory, legally approved international treaties become a part of the domestic legal system of a state without the need for additional domestic implementation, and international law can be directly applied in national courts[3]. This theoretical framework promotes greater consistency between domestic and international legal obligations and prioritizes the authority of international law in ensuring fundamental rights and treaty obligations.
The question of whether domestic or international law should be regarded as supreme has long been a fundamental issue in classical legal theory, most notably in the scholarship of Hans Kelsen. Through his work “Pure Theory of Law”, Kelsen developed a normative and conceptual framework that deliberately excluded political, moral, and sociological considerations, seeking instead to construct a science of law based on internal coherence and normative hierarchy.
In the legal context of Kelsen’s 1920s era, the dominant assumption was the primacy of state sovereignty, a view reflected in legal systems that frequently treated international law as subordinate to domestic legislation[4]. This approach is referred to as “Monism with Primacy of Domestic Law”,when a legal system adopts the presumption that domestic law is supreme. In this approach, international law loses its inherent binding force and is subject to the discretion of domestic legal authorities in determining its applicability[5].
In the early twentieth century, the assertion of domestic legal supremacy was rooted in the idea that the nation-state constituted the ultimate source of legal validity and was immune from normative obligations imposed by external legal orders. According to H. Kelsen, this form reflects a legal order when states retain full control over the creation and recognition of legal norms. International law is considered binding only to the extent that it is implemented into domestic law.
According to this perspective sovereignty remains at the core principle of state’s legal authority while the legal validity of the state taking precedence over the international legal community. The state holds full power to refuse international obligations for the reason of state sovereignty. As a result, the status of international law is conditional and dependent on recognition by national courts. It does not possess inherent authority but gains legal effect only through the selective approval of domestic legal systems[6]. H. Kelsen’s jurisprudential approach provides a structural and ideological explanation of how sovereignty and legal authority themselves may function as tools of imperialism in a legal-theoretical sense[7]. Thus the idea of “legal imperialism”, which later developed as a modern legal concept, did not emerge only from the idea of postcolonial experience, but from H. Kelsen’s theory about sovereignty and legal authority in the early twentieth century[8]. Postcolonial critiques of legal imperialism focus largely on the historical and political legacy of colonialism where international law was used to enforce unequal power relations and justify colonization[9].
The model of Monism offers a comprehensive framework rooted in the privilege of the sovereignty of the state. The French Constitution of the Fifth Republic 1958 delivers the concept of monist legal model with the primacy of domestic law[10]. Following Article 55, international treaties, once duly ratified and published, become directly applicable in domestic law without the need for transformation, but, in cases of conflict, the constitution must be amended before such treaties can take effect[11].
France signed the Rome Statute of the International Criminal Court in 1998, and it was ratified in 2000. However, the French Constitutional Council determined that Article 27 of the Rome Statute conflicted with constitutional provisions concerning immunity and sovereignty, as it provides for refusal of immunities of heads of state and government and allows investigative powers of the International Criminal Court on the French territory. In 1999, France introduced some amendments in its Constitution before ratifying, as certain provisions were found incompatible with the constitution[12].
This demonstrates the fact that the protection of fundamental human rights and the treaty obligations may depend on domestic legal nature and political will of the state when domestic legal systems emphasize constitutional supremacy. While this approach reflects the historical dominance of the state-centric legal authority, it effectively undermines the universal character and autonomous authority of international law. A critical criticism is that the model’s weakness lies in its tendency to reduce international law to a conditional set of norms, whose legal force depends entirely on domestic recognition.
Following the First World War, debating about the limits of international law and the rights of nations strengthened a particular viewpoint about legal authority of sovereign states. Despite the creation of interstate organizations like the League of Nations, countries continued to defend the supremacy of their domestic laws by giving a priority to a constitutional autonomy and their status as independent sovereign entities[13]. H. Kelsen acknowledged that this construction was logically consistent within the framework of his Pure Theory of Law because it treats law as a hierarchy system of norms, however he also emphasized that it was not inevitable or grounded in any natural order. The elevation of domestic law to a position of supremacy is the result of a particular legal assumption that is shaped by the historical and political context in which a legal system operates[14].
From H. Kelsen’s perspective, the dominance of one of the legal systems, international or domestic law, should be understood not as a political or ideological imposition, but as a logically coherent arrangement within the legal theory. It reflects a structured legal order where the primacy of a domestic legal norm is presupposed by the legal community. However, this configuration is not inevitable as it depends on the choice of a Grundnorm (basic norm),which is shaped by the historical and political context of the state’s legal system. H. Kelsen defines the Grundnorm as the basic norm which all other legal norms derive their validity from, and it is not a positive law created by any authority, but rather a logical presupposition that entails the validity of a legal system.
The Grundnorm can be described as a «presupposed norm» that serves as the starting point for the entire legal system to prevent an endless cycle of justification for legal validity. This chain of validation extends until one arrives at the highest norm, the basic norm of a legal system, and without a stopping point, this process would continue indefinitely, with each norm requiring justification from another higher norm, which H. Kelsen recognized as a logical impossibility[15]. These norms function within H. Kelsen’s legal theory as a necessary presupposition that ensures internal consistency and foundational authority within the legal order[16].
H. Kelsen’s hierarchy of norms is foundational to monism in international law with the concept of Grundnorm,which is a presupposition that confers validity to the international legal system. Under this configuration, international law is supreme, and domestic law derives its validity from international legal basic norms. While he acknowledged that this was not logically necessary, he considered it preferable for maintaining the unity and universality of law.
According to this perspective, when the domestic courts conflict with international law, international legal norms prevail over the domestic legal system or even sometimes constitutional law[17]. This approach is often referred to as “Monism with Primacy of International Law”, since it positions international legal obligations above all forms of domestic legal sources within a unified legal system of “pure monism”[18].
Under the concept of H. Kelsen’s monism international law can be applied directly within the domestic system without the need for specific legislative transformation or incorporation, since both sets of legal norms are part of a single unified system. H. Kelsen saw his monist theory as a challenge to the traditional dogma of an absolute state sovereignty, where the existence and competence of states’ legally coordinated system are determined by international law. H. Kelsen believed that the broader acceptance of this monistic framework would contribute to the growing centralization and effectiveness of international law and promote the development of global legal order and governance.
Hersch Lauterpacht, one of the most influential jurists and legal scholars of the twentieth century, made significant contributions to the development of the monist theory in international law. He advanced the idea that international law and domestic law should not be considered as two separate systems, but rather as components of a unified legal framework oriented toward the protection of fundamental human rights[19].
Diverging from Hans Kelsen’s legal positivist monism, H. Lauterpacht proposed a normative and humanistic form of monism that placed the individual at the center of the international legal order and the supremacy of international law was grounded not merely in formal legal hierarchy, but in its moral authority and universal applicability on human right perspective[20]. His work played a pivotal role in shaping a post-war international legal thought, particularly by promoting the view that international law creates direct rights and obligations for individuals.
This approach reflects the Staatkundig Gereformeerde Partij (SGP) case in the Netherlands, where some women’s rights organizations challenged the party’s policy which excluded women from standing for election. They argued that it could be inconsistent with its obligations under the European Convention on Human Rights, particularly Article 14 (prohibition of discrimination) and Article 3 of Protocol No. 1 (right to free elections).
This challenge was supported by 1983 Dutch Constitution – according to Article 93 (self-executing treaty provisions have direct effect once published) and Article 94 (national laws inapplicable if they conflict with binding international treaties) domestic courts can disregard any law that contradicts a directly applicable international treaty, even if it hasn’t been implemented in the domestic system. Individuals can enjoy their rights under the European Convention on Human Rights directly regardless of any possible conflict with the provisions in the domestic legislation.
In 2005, a group of organizations led by the feminist Clara Wichmann Foundation and other philanthropic organizations sued both SGP and the Dutch state. The court dismissed the claim directly against SGP but ruled against the Dutch state. The courts ruled that the State was obliged to take measures against discrimination of women by the SGP were required referring mainly to international treaties (CEDAW)[21]. The court ordered the state to suspend public funding for the SGP due to the human rights violations, sparking a national debate on gender equality and political party autonomy[22].
The state and the SGP appealed to the Supreme Court, the highest judicial institution for civil cases in the Netherlands. In 2006, The SGP amended its rules to allow women to become members but still excluding women from standing election. In 2007, the appeal court ruled that the Dutch state should act against the SGP, as women should be eligible to stand for election within this political party. The state again appealed these decisions but in 2010 the Supreme Court ruled against the state’s appeal, as the state cannot tolerate discrimination against women and should act against the SGP. In 2013, the SGP officially changed its charter to allow women to participate in elections[23].
This case made a significant impact on the Netherlands legally as well as politically and demonstrates that international obligations may affect political parties in a monist system where international law prevails over domestic practices. It confirmed the superiority of international human rights law, increased the state’s obligation to prevent discrimination, and allowed courts to override conflicting domestic laws.
Before the landmark judgment, a series of earlier efforts had already been made to challenge the party’s discriminatory stance toward women[24]. These challenges began as early as the 1980s, when individual complaints were filed but proved legally unsuccessful and led to no substantive changes. In 1993, several women reported discrimination to the police, yet no action was taken. During this period, the Dutch state also declined to act against the SGP and continued to subsidize the party as it had done since 1999.
In the subsequent SGP case, women’s rights organizations relied on Article 7 of the Convention on the Elimination of All Forms of Discrimination against Women 1979 (CEDAW), which the Netherlands had signed in 1980. However, Dutch courts held that the provision was non-self-executing, meaning it could not be directly invoked to challenge the party’s exclusion of women from candidacy. The government maintained that Dutch law was already in accordance with the relevant international conventions and did not require any amendments, therefore, it refused to penalize the party, holding that existing law was sufficient to address any discriminatory practices.
This case demonstrates that, although the Netherlands operates under a monist system that recognizes the primacy of international law not all international norms enjoy equal enforceability. Non-self-executing treaties may fail to provide immediate remedies, whereas self-executing instruments can be directly enforced by domestic courts. The SGP case therefore highlights the practical limitations of monism in safeguarding international obligations at the domestic level.
However, this theoretical model mainly supports the idea of a unified legal order in which international law is directly applicable and hierarchically superior, thus it can promote human rights protection, global governance, and treaty enforcement. A critical limitation lies in the assumption that domestic legal systems are structurally and politically needed to accept the supremacy of international norms.
“Monism with the Primacy of International Law” continues to serve as a normative ideal for a unified global legal order. However, its implementation reveals persistent tensions between international obligations and domestic legal autonomy, underscoring that the authority of international law, even when grounded in a rationalist framework like H. Kelsen’s approach, might be challenged by political interests and constitutional structures of sovereign states.
H. Lauterpacht’s humanistic form of monism marked a significant evolution in international legal theory by shifting the central focus from the state to the individual. By emphasizing the inherent dignity and rights of individuals, H. Lauterpacht reframed international law not merely as an inter-state mechanism but as a source of enforceable rights and obligations directly applicable to individuals within domestic legal systems. While both H. Kelsen’s and H. Lauterpacht’s approaches emphasize the unity of the international and domestic legal orders, they still do not clear up the relationship between them. However, there is another notable contrasting perspective, which rejects the idea of a single, unified legal system and views international and domestic law as two separate and distinct orders, namely dualism.
The Dualism is also a major doctrine approach to view the correlation between international and domestic legal systems, which is grounded in the assumption that two distinct legal systems operate independently depending on the nature of their respective sources, the entities involved, subjects, and their normative aims. Dualism holds the view that international law governs the relations between sovereign states, while domestic law regulates the conduct of individuals within the state. Since both systems are considered autonomous, international law does not automatically become part of the domestic legal system even after a state has ratified an international treaty, and it requires incorporation through specific constitutional or legislative procedures to acquire validity within the domestic legal order[25].
Triepel’s work, particularly his book “Völkerrecht und Landesrecht” (“International Law and Domestic Law”) published in 1899, emphasized that individuals are not direct subjects of international law but merely its objects, while states remain the primary subjects, and he further argued that law is fundamentally a “product of will” with his dualist doctrine asserting that international law, created through the “common will” (Gemeinwille) of states, acquires binding force within the domestic legal order only through positive constitutional or legislative action[26]. In this view, conflicts between international and national law emerge naturally due to their autonomy and differing normative legal frameworks, and Triepel’s dualism provides both practical and theoretical foundation for understanding these tensions.
Dionisio Anzilotti, widely recognized for his contributions to positivist theory and dualist doctrine, also argued that international law does not affect directly domestic legal systems unless it is expressly incorporated through national legislation, emphasizing that domestic courts, as institutions within the domestic legal system, are limited to adjudicating disputes between subjects of domestic law based on rules that are recognized as part of the national legal order[27]. This view reflected his belief that each legal system maintained its own validity and binding character within their respective spheres with no automatic hierarchy between international and domestic legal norms. D. Anzilotti agreed with Triepel’s perspective on dualism, but he advanced by grounding the binding force of international law less in the sociological fact of the collective will and more in the fundamental principle “pacta sunt servanda” (“treaties must be abided by”), while domestic law always expresses the will of a single state[28].
D. Anzilotti’s commitment to legal positivism emerged from his early philosophical work, particularly his “critique of Herbert Spencer’s conception of justice (1892).” He rejected natural law theory in two fundamental criticisms that would shape his entire approach to the international legal theory[29]. First, he argued that natural law was internally inconsistent, undermining its theoretical coherence. Second, it neglects the socially constructed nature of legal norms, that legal forms being shaped by the way people understand and apply natural conditions rather than by the conditions themselves. This strict rejection of natural law seems to overlook the potential contribution of universal moral principles to the development and legitimacy of international legal norms.
The examination of H. Triepel’s and D. Anzilotti’s dualist theories demonstrates how their strict positivist separation between international and domestic legal systems provided doctrinal clarity and protected state sovereignty. While H. Triepel focused on the “common will” of states, D. Anzilotti through the principle of “pacta sunt servanda” offered a coherent framework that explained why international law required incorporation into national systems to acquire binding force. However, the inflexibility of this approach has become increasingly at odds with the modern international legal order, which recognizes jus cogens norms, direct effect of international obligations on individuals, and individual rights. This approach highlights that classical dualism remains only foundational and needs to evolve toward more integrative and flexible approaches capable of reconciling international obligations with domestic and constitutional practice.
A transformation theory is an important part of a dualistic approach, that regards international law and domestic law as distinct and independent spheres, which are not merely different branches of law but are distinct legal orders. They are two circles that, at most, touch but never overlap[30]. Under this theory, international norms do not automatically acquire domestic legal effect upon ratification of treaties. They must be formally “adopted” or “transformed” into national law through specific legislative procedures before being applied by domestic courts.
However, the requirement of transformation may result in delays, incomplete incorporation, or inconsistencies, potentially leading to conflicts between state’s international commitments and its internal legal framework. This approach protects the sovereignty and democratic accountability of the national legislature by ensuring that international obligations become binding within the state only after a parliamentary approval[31]. A. Cassese also views that the dualistic approachrequires formal incorporation of international norms through transformation is increasingly seen as problematic, since it can delay or weaken the enforcement of international obligations, especially in human rights[32].
H. Triepel and D. Anzilotti’s theories provide a classical foundation for this approach by emphasizing an autonomy of international and domestic legal systems and the requirement of explicit legislative incorporation for international law to take effect domestically, while the practical operation of dualism and transformation theory demonstrates both its institutional strengths and normative limitations.
The United Kingdom ratified the European Convention on Human Rights (ECHR) in 1951, but the ECHR did not have direct application in domestic law until the Parliament enacted the Human Rights Act 1998, which came into force in 2000, while UK courts followed a strict dualist approach. This almost 50-year gap illustrates how parliamentary sovereignty and democratic accountability were preserved at the cost of delaying the domestic enforcement of treaty-based rights.
This experience shows how constitutionally required transformation may create structural barriers in the legal order, and strict dualism that emphasized state sovereignty no longer aligns with the realities of the modern international legal order, while contemporary legal scholarship increasingly focuses on the recognition of jus cogens norms and individual human rights. Flexible approaches are needed to grant domestic courts greater discretion to apply international norms without full legislative incorporation, preserving the democratic legitimacy of transformation theory while removing structural barriers to their domestic application.
Classical theoretical approaches provided the understanding of the relationship between international and domestic legal systems, but their limitations in meeting the demands of a modern legal order have prompted a search for more adaptable models that can balance states’ constitutional autonomy with contemporary international accountability that increasingly deals with human rights.
Contemporary or Modern Doctrine Approaches
While classical models remain influential in legal scholarship, they often prove insufficient to address the complex and evolving ways in which international and national legal norms interact in different national contexts and various jurisdictional systems. Indeed, contemporary legal practice demonstrates that most states do not adhere strictly to either monism or dualism. Instead, they adopt hybrid or other approaches, influenced by their respective constitutional frameworks, legal traditions, ideological trajectories, and political considerations. Shaw argued that the distinction between the two legal systems is becoming increasingly difficult to separate in practical terms, as international law continues to expand its influence on domestic law[33].
Alfred Verdross’s concept of moderated monism serves as an important transitional theoretical link between classical and modern approaches to the relationship between international and domestic legal systems. His theory developed during a time of a significant transformation in international law, as he viewed that the consequences of the World War I and the creation of the League of Nations called for new legal theories that could reconcile the unity of international law with the functional independence of national legal systems[34].
A. Verdross argued that neither classical monism nor dualism adequately captured the complex interaction between international and domestic legal systems. The concept of moderate monism departed from H. Kelsen’s strict hierarchical model of a unified normative order while still retaining a degree of autonomy, such that a conflict between the two systems does not result in the automatic nullification of the subordinate norm but rather necessitates a legal assessment based on contextual factors[35].
The theoretical foundations of A. Verdross’s approach rested on several key principles that distinguished it from classical formulations. In a contrast to A. Kelsen’s theory, Verdross integrated value-oriented reasoning and natural law elements into his framework, anticipating the later recognition of jus cogens norms. A. Verdross defined jus cogens as “ethical minimum recognized by all the states of the international community,” encompassing fundamental obligations such as maintaining domestic law and order, defending against external aggression and protecting individuals[36].
This definition reflects A. Verdross’s view that certain core legal principles possess a universal character, are binding on all states irrespective of their consent and constitute the foundational norms that sustain the structure and legitimacy of the international legal order, and it later contributed to the development of modern legal theories such as international constitutionalism.
A. Verdross also argued that dualism is inconsistent because a state cannot be separated from the international legal system, a state is a human and territorial community unified by a functioning legal order, whether based on a written or unwritten constitution, and this legal order operates within the broader international community, thus, anyone who exercises authority within that system is considered as a state organ[37]. A. Verdross maintains that states are part of a global legal community governed by universal international law, which requires an international constitutional framework among sovereign entities[38]. While respecting sovereignty, contemporary international law increasingly influences domestic legal systems, even those that govern relations between sovereign states rather than individuals, by promoting the rule of law and obliging states to protect human rights, as reflected in Article 56 of the UN Charter[39].
A. Verdross also expressed the view that international law is a consistent legal system, which should be grounded in an underlying constitutional structure, while the “general part of public international law” is the “Constitution of the International Legal Community”, focusing on the fundamental and unified character rather than a random collection of treaties and customs[40]. According to this perspective, the UN Charter was later widely recognized as the written constitution of the international legal institution, that not only shapes the relationship between states but also guides the functioning of international organizations and the interpretation of customary international law.
The concept of jus cogens, as influenced by A. Verdross, is seen in the development of the Vienna Convention on the Law of Treaties 1969[41], while Article 53 states that any treaty conflicting with a peremptory norm of general international law is automatically void. This principle reflects the idea that international law is no longer purely consensual but has constitutional elements binding on all states, regardless of explicit agreement. Such norms, including the prohibitions against genocide, torture, and aggression, serve as a legal and moral foundation of the international legal community. Although the International Court of Justice has also been hesitant to thoroughly engage with jus cogens, their existence is broadly acknowledged as an element within the functioning of the international legal system[42].
A. Verdross’s theory of international constitutionalism offers a crucial foundation for understanding the normative unity and structural coherence of contemporary international law. The rejection of dualism and advocacy for a global legal order grounded in fundamental principles anticipate the increasing convergence of domestic and international legal obligations. Although the practical implementation remains incomplete and inconsistent, the theoretical framework continues to influence legal scholarship and jurisprudence by providing a normative standard for evaluating the legitimacy and hierarchy of legal norms within both international and domestic legal systems.
Unlike monism and dualism, the theoretical foundation of modern legal pluralism emerged from the John Griffiths’s seminal 1986 work[43]. He claims that the concept of the legal pluralism reflects the coexistence of multiple legal orders within a single social field. Legal pluralism sees the legal authority does not lie in a single source, nor does it organize legal authority either into hierarchy or separation, while it recognizes the multiplicity of legal systems including international, domestic, religious, and even private, which can exist at the same time and often overlap or influence each other[44].
When domestic law conflicts with international law, legal pluralism does not always advocate for automatic primacy of one over the other but instead it supports finding a balance based on dialogues, cooperations, and the specific negotiations. Domestic legal institutions are encouraged to consider carefully how to apply international law, either if it aligns with their constitutional values or by finding alternative way to apply it in part, domestic courts, for instance, can selectively integrate international norms depending on their perceived legitimacy, constitutional values, and the practical implications of enforcement[45].
It also reflects that not all international law must be binding and the “soft law”, which refers to the concept of international principles or guidelines without legal force, can still influence national courts and domestic legal systems because of their importance and/or moral value. Legal pluralism, therefore, shift the analytical focus from classical hierarchy of supremacy to processes of engagement, negotiation, and adaptation between normative systems[46].
In contemporary environmental law, instruments such as the Paris Agreement and the UN Sustainable Development Goals (SDGs), while not legally binding, have considerably influenced national legal reforms and policy agendas across different jurisdictions. Courts and legislatures have drawn upon these instruments to justify their legal interpretations and legislative actions, exemplifying a pluralistic approach to influence through normative frameworks rather than coercion.
Legal pluralism constitutes a practical way to understand contemporary legal order because its concept provides for coexistence of different legal traditions and offers more flexible ways of bringing international law into domestic legal systems. This approach lies more closely with the reality of modern world, where international rules affect many areas such as human rights, trade, and environmental protection.
Instead of seeing law as a single and strict system with one highest authority, legal pluralism views it as many legal systems co-functioning at the same time in a flexible way. This creates a more complex but realistic legal environment where different rules can co-exist, overlap or even conflict. This view also helps to explain why cooperation and dialogue between legal systems are important for making international law effective and legitimate.
The relationship between international law and domestic legal systems has developed through different theoretical approaches, each offering distinctive understandings but also facing significant limitations. Classical monism promotes legal unity and the direct applicability of international norms but often underestimating domestic constitutional limitations and political resistance. While the Dualism emphasizes state sovereignty through the separation of two distinct legal orders, its requirement to transform from international law into domestic law can delay domestic implementation of international obligations, especially in urgent cases such as human rights protection. The moderate monism theory seeks to balance these tensions by recognizing international norms, including jus cogens, while advocating for global constitutional structure in the legal order.
While giving primacy to international law generally strengthens accountability at the domestic level, the recognition of jus cogens norms bolsters this framework by imposing universally binding obligations that transcend state consent. But its effectiveness varies depending on whether treaties are self-executing, the constitutional framework in place, and the willingness of domestic courts to absorb international norms. Although jus cogens norms bind all states, domestic courts often hesitate to apply them when they conflict with constitutional provisions or political priorities, and political resistance can lead to selective enforcement, undermining their universality and legitimacy.
Legal pluralism has emerged as a contemporary alternative that rejects the notion of legal supremacy in a hierarchical structure as well as the nature of separate forms. It recognizes the co-existence of multiple legal orders within a single field. This flexibility reflects the realities of globalized governance, where ‘soft law’ instruments and informal standards increasingly influence domestic legal systems. However, pluralism’s lack of clear criteria for resolving normative conflicts can lead to inconsistent outcomes. These challenges highlight the need for frameworks that support judicial dialogue and structured coordination to balance state’s sovereignty and treaties obligation.
Future studies on the relationship between international and domestic legal systems should focus on developing of adaptive approaches suited to the needs of modern legal systems. Such integrated models should address the sensitive and complex nature of binding legal obligations in the contemporary world, pay more attention to a comparative constitutional analysis across diverse judicial practices and recognize domestic courts as essential actors in mediating and bridging different legal orders.
Achieving this objective requires a deeper understanding of how international law is applied in practice and how national legal systems can effectively incorporate international standards without undermining democratic principles or constitutional identity. This includes a comprehensive examination of the role of constitutional sovereignty in reconciling international and domestic norms, as well as the identification of institutional mechanisms that enable consistent implementation of international obligations across diverse jurisdictions.
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[1] Spaak T. Kelsen on Monism and Dualism // Basic Concepts of Public International Law: Monism & Dualism / ed. by M. Novakovic. – Belgrade: Alter DOO; Faculty of Law, University of Belgrade; Institute of Comparative Law, 2013. – P. 323
[2] Kelsen H. Pure Theory of Law / transl. from the 2nd rev. German ed. by M. Knight. – Berkeley: University of California Press, 1967. – Originally published in German as Reine Rechtslehre, 2nd ed. – Vienna: Franz Deuticke, 1960. P – 194.
[3] Starke J.G. Monism and Dualism in the Theory of International Law // Normativity and Norms: Critical Perspectives on Kelsenian Themes / ed. by S.L. Paulson. – Oxford: Oxford University Press, 1999. – P. 537.
[4] Langford P., Bryan I. Hans Kelsen’s Theory of Legal Monism: A Critical Engagement with the Emerging Legal Order of the 1920’s // Journal of the History of International Law. – 2012. – Vol. 14, No. 1. – P. 51–86.
[5] Rigaux F. Hans Kelsen on International Law // European Journal of International Law. – 1998. – Vol. 9. – P. 325.
[6] Kelsen H. General Theory of Law and State. – Cambridge, MA: Harvard University Press, 1945. – P. 388–389.
[7] von Bernstorff, Jochen, Hans Kelsen on Judicial Law-Making by International Courts and Tribunals: A Theory of Global Judicial Imperialism? European Society of International Law (ESIL) Annual Conference (Oslo), 2015. – Conference Paper No. 8/2015. – Vol. 5. – P. 11.
[8] Gozzi G. International Law, Peace, and Justice: Hans Kelsen’s Normativism // Rights and Civilizations: A History and Philosophy of International Law. – Cambridge: Cambridge University Press, 2019. – P. 141–165.
[9] José- Manuel Barreto Cerberus: Rethinking Grotius and the Westphalian System // International Law and Empire: Historical Explorations. First Edition Martti Koskenniemi, Walter Rech, and Manuel Jiménez Fonseca: Oxford University Press, 2016. – P. 149.
[10] Decaux E. Ratification et application du Statut de la Cour pénale internationale par la France // Revue Trimestrielle des Droits de l’Homme. 2002. No. 49. P. 243–267.
[11] French Constitution of the Fifth Republic, 4 October 1958, as amended. – P. 23.
[12] European Commission for Democracy through Law (Venice Commission), Second Report on Constitutional Issues Raised by the Ratification of the Rome Statute of the International Criminal Court, Study no. 498/2008, CDL-AD(2008)031, Strasbourg, 4 November 2008, adopted at the 76th Plenary Session (Venice, 17-18 October 2008), based on comments by Mr Peter Paczolay (Member, Hungary). – P. 5.
[13] Koskenniemi M. From Apology to Utopia: The Structure of International Legal Argument. – Cambridge: Cambridge University Press, 2005. – P. 120–125.
[14] Kelsen H. Pure Theory of Law / transl. from the 2nd rev. German ed. by M. Knight. – Berkeley: University of California Press, 1967. – Transl. from: Kelsen H. Reine Rechtslehre. – 2., völlig neu bearb. Aufl. – Wien: Franz Deuticke, 1960. – P. 335.
[15] Shivakumar D. The Pure Theory as Ideal Type: Defending Kelsen on the Basis of Weberian Methodology // The Yale Law Journal. – 1996. – Vol. 105, No. 5. – P. 1383–1414.
[16] Roger S. Clark. Hans Kelsen’s Pure Theory of Law // Journal of Legal Education – 1969. – Vol. 22. – P. 191.
[17] Kelsen H. Pure Theory of Law / transl. from the 2nd rev. German ed. by M. Knight. – Berkeley: University of California Press, 1967. – Transl. from: Kelsen H. Reine Rechtslehre. – 2., völlig neu bearb. Aufl. – Wien: Franz Deuticke, 1960.
[18] Shaw M.N. International Law. – 7th ed. – Cambridge: Cambridge University Press, 2014. – P. 103–105.
[19] Lauterpacht H. The Function of Law in the International Community. – Oxford: Oxford University Press, 1933.
[20] Kolb R. Hersch Lauterpacht and Human Dignity // Human Dignity and International Law / eds. M.D. Dubber, J. Moran, T. Weigend. – Leiden; Boston: Brill, 2020. – Ch. 3.
[21] Brink J., ten Napel H.-M. The Dutch Political Reformed Party (SGP) and Passive Female Suffrage: A Comparison of Three High Court Judgments from the Viewpoint of Democratic Theory // Utrecht Journal of International and European Law. – 2013. – Vol. 29, No. 76.
[22] International IDEA. Gender-Targeted Public Funding for Political Parties: A Comparative Analysis. Stockholm: International Institute for Democracy and Electoral Assistance, 2014. P. 20.
[23] Oomen B. M., Guijt J., Ploeg M. CEDAW, the Bible and the State of the Netherlands: the struggle over orthodox women’s political participation and their responses // Utrecht Law Review. – 2010. – Vol. 6, No. 2.
[24] Advocacy for the right to stand for election – Netherlands: The case against discrimination of women in the SGP // European Institute for Gender Equality (EIGE).
[25] Shaw M.N. International Law. – 7th ed. – Cambridge: Cambridge University Press, 2014. – P. 129–134.
[26] Beenakker E.B. The Implementation of International Law in the National Legal Order: A Legislative Perspective (Meijers-reeks). – Amsterdam: University of Amsterdam, 2018. P. 26 – 27.
[27] Gaja G. Positivism and Dualism in Dionisio Anzilotti // European Journal of International Law. – 1992. – Vol. 3, No. 1. – P. 35.
[28] Hovell D. The Elements of International Legal Positivism // Current Legal Problems. – 2022. – Vol. 75, No. 1. – P. 71–109.
[29] Gaja G. Positivism and Dualism in Dionisio Anzilotti // European Journal of International Law. – 1992. – Vol. 3, No. 1. – P. 124.
[30] Translation of a notable original passage Triepel H. Völkerrecht und Landesrecht. – Leipzig: C.L. Hirschfeld, 1899. «Völkerrecht und Landesrecht sind nicht nur verschiedene Rechtsteile, sondern auch verschiedene Rechtsordnungen. Sie sind zwei Kreise, die sich höchstens berühren, niemals schneiden.»
[31] Beenakker E.B. The Implementation of International Law in the National Legal Order: A Legislative Perspective (Meijers-reeks). – Amsterdam: University of Amsterdam, 2018. P. 35.
[32] Cassese A. International Law. – 2nd ed. – Oxford: Oxford University Press, 2005. – P. 213–215.
[33] Shaw M.N. International Law. – 7th ed. – Cambridge: Cambridge University Press, 2014. – P. 129–134.
[34] Kleinlein T. Alfred Verdross as a Founding Father of International Constitutionalism? // Goettingen Journal of International Law. – 2012. – Vol. 4, No. 2. – P. 385–416.
[35] Simma B. The Contribution of Alfred Verdross to the Theory of International Law // European Journal of International Law. – 1995. – Vol. 6, No. 1. – P. 33–54.
[36] Janis M.W. The Nature of Jus Cogens // Connecticut Journal of International Law. – 1988. – Vol. 3, No. 2. – P. 359.
[37] Verdross A. Forbidden Treaties in International Law: Comments on Professor Garner’s Report. // The American Journal of International Law, vol. 31, no. 4, 1937, pp. 571–577.
[38] O’Donoghue A. Alfred Verdross and the Contemporary Constitutionalization Debate // Oxford Journal of Legal Studies. – 2012. – Vol. 32, No. 4. – P. 799–822.
[39] Simma B. The Contribution of Alfred Verdross to the Theory of International Law // European Journal of International Law. – 1995. – Vol. 6, No. 1. – P. 46.
[40] Kleinlein T. Alfred Verdross as a Founding Father of International Constitutionalism? // Goettingen Journal of International Law. – 2012. – Vol. 4, No. 2. – P. 389.
[41] ILC Draft Articles on the Law of Treaties with commentaries (1966) // Yearbook of the International Law Commission, 1966, Vol. II. – P.247–294.
[42] Orakhelashvili A. Peremptory Norms in International Law. Oxford: Oxford University Press, 2008. – P.489–517.
[43] Griffiths J. What is Legal Pluralism? // The Journal of Legal Pluralism and Unofficial Law. 1986. Vol. 18, No. 24. P. 1–55.
[44] Michaels R. Global Legal Pluralism // Annual Review of Law and Social Science. – 2009. – Vol. 5. – P. 243–282.
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Информация об авторе:
Сой Ян Наунг, аспирант Юридического института Российского университета дружбы народов имени Патриса Лумумбы (РУДН)
Information about the author:
Soe Yan Naund, PhD student at the Law Institute of the RUDN University named after Patrice Lumumba
