Treaty of Rome: Legal Foundations of European Integration

I. Introduction

The Treaty of Rome marks the legal starting point of Europe’s most ambitious experiment in institutionalized integration: a project that transformed classical intergovernmental cooperation into a durable legal order capable of generating binding rules, common policies, and enforceable obligations across multiple states. Signed on 25 March 1957 and entering into force on 1 January 1958, the Treaty of Rome was not drafted as a symbolic declaration of political unity. It was conceived as an operational legal framework designed to restructure economic relations among its signatories through law, institutions, and long-term commitments.

In public international law, the Treaty of Rome is significant because it departed from the dominant treaty model of the mid-twentieth century. Instead of relying primarily on reciprocal obligations and diplomatic enforcement, it created a Community with clearly defined tasks, enumerated competences, and permanent institutions entrusted with implementing, supervising, and interpreting the treaty. The establishment of a common market was not framed as an aspirational policy objective but as a legally structured process, accompanied by detailed obligations on tariff dismantling, market access, and regulatory coordination. This legal precision distinguished the Treaty of Rome from earlier forms of economic cooperation and explains why its influence extends well beyond its historical context.

The enduring relevance of the Treaty of Rome also lies in its treatment of sovereignty. The founding states did not abandon sovereignty, but they accepted binding constraints on unilateral action in areas covered by the treaty. By committing to eliminate customs duties, prohibit quantitative restrictions, and approximate national laws where necessary for the functioning of the common market, states acknowledged that certain economic decisions could no longer be exercised independently without undermining shared objectives. This recalibration of sovereignty through law remains one of the most consequential contributions of the Treaty of Rome to international legal thought.

Another reason the Treaty of Rome still matters is its quasi-constitutional character. Unlike many international agreements concluded for fixed periods or limited purposes, it was designed to operate indefinitely and to evolve through amendment rather than replacement. This choice enabled continuity in legal obligations while allowing institutional adaptation over time. Subsequent treaty reforms expanded competences, adjusted decision-making procedures, and deepened integration, but they did so by building on the legal foundations laid in 1957. Understanding contemporary European Union law, therefore, requires an appreciation of the original architecture established by the Treaty of Rome.

The treaty is also central to understanding how economic integration was deliberately used as a legal strategy for peace and stability. The founders assumed that sustained cooperation in economically sensitive sectors would reduce incentives for conflict by increasing interdependence and by embedding national economies within a shared legal framework. The Treaty of Rome operationalized this assumption by linking market integration with institutional oversight and judicial enforcement. In this sense, it represents a legal response to the failures of both power politics and loose intergovernmental coordination in post-war Europe.

Today, the Treaty of Rome remains relevant because it continues to shape debates that extend far beyond the European context. Questions about the limits of state autonomy, the legitimacy of supranational rule-making, the role of courts in enforcing international commitments, and the capacity of law to manage deep economic interdependence all find an early and sophisticated expression in the Rome framework. The treaty demonstrates that integration through law is not merely a political choice but a structural legal project that requires carefully designed institutions, enforceable norms, and long-term commitment.

For these reasons, the Treaty of Rome should not be read as a closed historical chapter. It should be understood as a foundational legal experiment whose logic continues to inform contemporary international governance. Its relevance lies not only in what it created in 1957, but in how it redefined what international treaties could realistically achieve when law, institutions, and economic integration are deliberately combined.

II. Historical Context and Legal Precedents

The Treaty of Rome emerged from a specific historical moment marked by the collapse of Europe’s traditional balance-of-power system and the failure of pre-war models of interstate cooperation. The devastation of the Second World War exposed the limits of classical sovereignty-centered diplomacy and revealed the inadequacy of loose treaty arrangements in managing economic recovery, security concerns, and political stability. European states faced the dual challenge of reconstruction and preventing the recurrence of systemic conflict in a continent that had experienced two world wars within a single generation.

Early post-war cooperation initiatives reflected this awareness. The establishment of the European Coal and Steel Community in 1951 represented a decisive legal experiment: strategic industries central to military capacity were placed under a common authority, reducing the possibility of unilateral rearmament and fostering mutual dependence. This arrangement introduced a functional approach to integration, grounded in the idea that cooperation in concrete economic sectors could generate stability more effectively than abstract political commitments. The experience of the Coal and Steel Community demonstrated that binding rules, centralized supervision, and shared institutions could operate successfully across national boundaries.

The Treaty of Rome was built directly on this precedent but expanded its scope and ambition. Instead of focusing on a limited set of industries, it aimed to restructure the general economic relations among participating states. The decision to pursue a common market reflected a legal judgment as much as a political one: fragmented national markets were seen as obstacles to growth, while tariff barriers and regulatory divergence were understood as sources of economic inefficiency and political friction. The treaty thus translated economic theory into legal obligation, committing states to progressive market integration through enforceable rules.

International developments also shaped the treaty’s design. The onset of the Cold War, the division of Europe into opposing blocs, and the vulnerability of Western European economies to external pressure reinforced the perception that deeper cooperation was necessary. Economic integration was treated as a stabilizing force capable of strengthening internal cohesion and enhancing collective resilience without requiring immediate political unification. This context explains why the Treaty of Rome prioritized economic mechanisms while leaving broader political integration implicit rather than explicit.

From a legal perspective, the Treaty of Rome drew on but also departed from existing models of international organization. Traditional organizations of the period relied heavily on unanimity, preserved wide discretion for member states, and lacked effective enforcement mechanisms. By contrast, the Rome framework introduced majority decision-making in defined areas, delegated implementation powers to a supranational executive body, and entrusted judicial oversight to a permanent court. These choices reflected lessons learned from the limitations of earlier intergovernmental institutions, including those created under the League of Nations system.

The treaty’s legal originality lies in its synthesis of functional integration and institutional permanence. It treated integration not as a temporary alignment of interests but as an ongoing legal process structured around common objectives, shared competences, and evolving obligations. This approach distinguished the Treaty of Rome from conventional trade agreements and positioned it as a foundational instrument in the development of modern regional integration law.

Understanding the historical context and legal precedents of the Treaty of Rome is essential because it clarifies why the treaty adopted its particular form. Its provisions were not accidental or purely ideological. They were the product of concrete historical failures, pragmatic experimentation with earlier communities, and a deliberate effort to design a legal order capable of sustaining cooperation under conditions of deep economic interdependence.

III. Structure and Dual Nature of the Treaty of Rome

The Treaty of Rome is structurally distinctive because it was not a single, unitary instrument pursuing one narrowly defined objective. It consisted of two legally separate but conceptually linked treaties: the Treaty establishing the European Economic Community and the Treaty establishing the European Atomic Energy Community. This dual structure reflects a deliberate legal strategy to advance integration through parallel but differentiated regimes, each tailored to the characteristics of the sector it governed. Understanding this dual nature is essential to appreciating both the scope and the limits of the original Rome framework.

The European Economic Community treaty formed the core of the integration project. It was designed as a comprehensive legal framework for economic integration across virtually all sectors of economic activity. Its provisions laid out the legal architecture of a common market, including detailed rules on customs unions, free movement, competition, approximation of laws, and common policies in areas such as agriculture and transport. The breadth of this treaty signals its systemic ambition: economic integration was not confined to trade liberalization but extended to the coordination of national economic policies and the gradual construction of a shared regulatory space.

By contrast, the Euratom treaty addressed a highly specialized and politically sensitive domain. Nuclear energy, at the time, was associated with both civilian development and military potential. Rather than fully integrating this sector into the general common market framework, the drafters opted for a distinct legal regime focused on research coordination, supply security, and safety standards. This separation illustrates an early recognition of differentiated integration, allowing cooperation to advance without forcing uniform solutions across all policy fields.

Structurally, both treaties shared institutional foundations. They relied on a common set of institutions tasked with legislative initiative, political decision-making, and judicial oversight. This institutional overlap ensured coherence between the two communities while preserving their legal autonomy. The decision to combine sectoral differentiation with institutional unity represented a novel approach in international treaty design, striking a balance between flexibility and systemic consistency.

Another defining feature of the Treaty of Rome’s structure is its temporal design. The treaties were concluded for an unlimited duration and incorporated transitional periods rather than fixed endpoints. Economic integration was conceived as a process governed by legal stages, not as an immediate transformation. Transitional provisions set out timetables for tariff reduction, market opening, and policy harmonization, embedding gradualism directly into the legal text. This approach reduced political resistance by allowing adjustment over time while preserving the binding nature of ultimate objectives.

The internal organization of the Economic Community treaty further reflects its dual character as both a policy programme and a constitutional framework. On one level, it enumerated specific activities and policies to be pursued collectively. On another, it established general principles governing the allocation of powers, the limits of institutional action, and the relationship between the Community and its member states. This combination of detailed regulatory commitments and abstract constitutional principles distinguishes the Treaty of Rome from classical commercial treaties, which typically avoid deep institutionalization.

The dual nature of the Treaty of Rome also manifests in its legal effects. It operated simultaneously as an international agreement binding sovereign states and as the foundational text of an autonomous legal order capable of producing norms with internal effect. This hybridity would later enable judicial doctrines that reinforced the treaty’s effectiveness, but its roots lie in the original structural choices made in 1957. The treaty was drafted to function continuously, generate secondary legislation, and adapt to economic and political change without constant renegotiation.

In sum, the structure and dual nature of the Treaty of Rome reveal a sophisticated legal design. By combining comprehensive economic integration with sector-specific cooperation, institutional unity with legal differentiation, and gradual implementation with permanent commitment, the treaty established a flexible yet durable foundation for European integration. This structural logic explains both its resilience over time and its central place in the development of supranational legal systems.

IV. Core Objectives and Principles of the Treaty of Rome

The core objectives of the Treaty of Rome were articulated with unusual clarity for an international agreement of its time. Rather than limiting itself to general statements of cooperation, the treaty defined a concrete task for the Community: the establishment of a common market and the progressive approximation of the economic policies of the participating states. These objectives were framed as legal commitments, not political aspirations, and they structured the entire architecture of rights, obligations, and institutional powers contained in the treaty.

At the center of the treaty’s objective structure lies the concept of the common market. The common market was conceived as an integrated economic space in which national barriers to exchange would be dismantled and replaced by uniform rules. This involved the elimination of customs duties and charges having equivalent effect, the prohibition of quantitative restrictions on trade, and the removal of obstacles to the movement of workers, services, and capital. The treaty treated these freedoms as interdependent components of a single legal system, designed to prevent partial integration that could distort competition or undermine market unity.

Closely linked to the common market objective was the principle of non-discrimination on grounds of nationality. This principle functioned as both a market rule and a broader normative commitment. By prohibiting discriminatory treatment within the scope of the treaty, the legal framework aimed to ensure that economic actors could participate in the common market under equal conditions. This principle reinforced market integration while simultaneously constraining national regulatory autonomy in areas covered by the treaty.

Another foundational objective was the creation of conditions for fair and undistorted competition. The Treaty of Rome did not assume that market integration alone would produce equitable outcomes. It therefore incorporated rules on competition and state intervention designed to prevent private or public practices that could fragment the common market. By addressing cartels, abuse of dominant positions, and certain forms of state aid, the treaty recognized that economic integration required active legal governance rather than passive deregulation.

The treaty also embedded the objective of economic and social cohesion. While the common market aimed at efficiency and growth, the drafters acknowledged the risk of uneven development among regions and sectors. The inclusion of mechanisms such as the European Social Fund and the commitment to reducing regional disparities reflected an early awareness that integration would be politically and legally sustainable only if its benefits were broadly shared. This objective introduced a corrective dimension to market integration, balancing efficiency with solidarity.

From a constitutional perspective, the Treaty of Rome was guided by principles governing the exercise of Community powers. The treaty specified that the Community would act only within the competences conferred upon it and only to achieve the objectives defined in the treaty. This principle of conferred powers established a legal boundary between Community action and national autonomy. At the same time, it implied that once competence was conferred, member states were bound to respect and facilitate the achievement of common objectives, limiting their freedom to pursue conflicting national measures.

Gradualism was another core principle embedded in the treaty’s design. Economic integration was not imposed instantaneously but structured through transitional periods and staged implementation. This principle served both legal and political functions. Legally, it allowed for the orderly development of the common market through predefined steps. Politically, it acknowledged the practical constraints faced by states adjusting to a new legal and economic environment, reducing resistance while preserving the binding nature of long-term commitments.

Taken together, the objectives and principles of the Treaty of Rome reveal a carefully balanced legal project. The treaty sought to integrate markets while preserving social stability, constrain state discretion while respecting national identities, and promote efficiency while embedding solidarity. These principles continue to inform the functioning of European integration and remain central to understanding the treaty’s lasting influence on international economic and institutional law.

V. Institutional Architecture and Distribution of Powers

The Treaty of Rome introduced an institutional architecture that departed fundamentally from the prevailing models of international organization in the mid-twentieth century. Instead of relying on ad hoc conferences or purely intergovernmental bodies, it established permanent institutions with distinct functions and legally defined powers. This structure was designed to ensure continuity, effectiveness, and legal certainty in the pursuit of the treaty’s objectives, particularly the construction and maintenance of the common market.

At the core of this architecture was the Commission, conceived as an independent executive body charged with promoting the general interest of the Community. The Commission was entrusted with the power of initiative in the legislative process, enabling it to propose measures necessary to achieve treaty objectives. This role reflected a deliberate choice to separate technical expertise and long-term policy orientation from short-term national political pressures. The Commission’s duty to act independently of national governments was a structural safeguard aimed at preserving the coherence of the integration project.

The Council occupied a different but equally central position. Composed of representatives of the member states, it functioned as the primary decision-making body in which national interests were articulated and reconciled. The Treaty of Rome assigned the Council legislative and policy-setting authority, often acting on proposals submitted by the Commission. In specific areas, the treaty introduced qualified majority voting, reducing the ability of individual states to block collective action. This partial departure from unanimity was a critical innovation, enabling the Community to act even in the presence of divergent national preferences.

The Parliamentary Assembly, later known as the European Parliament, was originally endowed with limited powers. Its role was primarily consultative and supervisory rather than legislative. Nevertheless, its inclusion in the institutional framework signaled an early commitment to representative participation and transparency. Over time, the presence of this body provided a foundation for the gradual expansion of parliamentary influence, illustrating how the treaty’s institutional design allowed for evolutionary development without structural rupture.

Judicial oversight was entrusted to the Court of Justice, which played a central role in safeguarding the legal integrity of the Community. The Treaty of Rome empowered the Court to ensure that the law was observed in the interpretation and application of the treaty. This included reviewing the legality of acts adopted by Community institutions and resolving disputes involving member states. By embedding judicial review within the institutional framework, the treaty ensured that integration would be governed by law rather than political discretion alone.

The distribution of powers among these institutions reflected a carefully calibrated balance. Legislative initiative rested primarily with the Commission, political authorization with the Council, advisory and supervisory functions with the Parliamentary Assembly, and legal interpretation with the Court. This separation of functions reduced the concentration of power and created mechanisms of mutual control. At the same time, the treaty required cooperation among institutions, making collective decision-making an intrinsic feature of Community governance.

The Treaty of Rome also addressed the relationship between Community institutions and member states. While states retained significant competencies, they were obliged to facilitate the achievement of Community objectives and to refrain from measures that could undermine them. This obligation reinforced the authority of Community institutions and limited the scope of unilateral national action in areas covered by the treaty. The result was a system in which authority was neither fully centralized nor entirely decentralized, but distributed across multiple levels of governance.

In institutional terms, the Treaty of Rome established a model that combined supranational and intergovernmental elements within a single legal framework. This hybrid architecture proved resilient and adaptable, allowing the Community to expand its activities and competencies over time. Its influence extends beyond the European context, serving as a reference point for the design of other regional integration arrangements seeking to balance effectiveness, legitimacy, and respect for state sovereignty.

VI. The Treaty of Rome and the Birth of Supranational Law

The Treaty of Rome marked a decisive moment in the evolution of international law by laying the structural foundations for a legal order that operated beyond the traditional confines of intergovernmental obligation. While formally concluded as an international treaty, its design enabled the emergence of supranational law: a body of norms capable of producing legal effects within domestic legal systems and constraining both state and institutional action through judicial enforcement.

This transformation was rooted in the treaty’s normative structure. The obligations set out in the Treaty of Rome were framed with a level of precision and operational detail that exceeded standard treaty practice. Provisions on customs duties, quantitative restrictions, competition rules, and market freedoms were not expressed as broad commitments dependent on further political agreement. They were drafted as concrete rules intended to be applied, interpreted, and enforced on a continuous basis. This legal density created the conditions for the treaty to function as a source of law rather than merely a contract among states.

Equally important was the treaty’s institutional enforcement mechanism. By establishing a permanent court with compulsory jurisdiction over disputes concerning the interpretation and application of the treaty, the Rome framework departed from the dominant reliance on diplomatic settlement or arbitration in international law. Judicial review was not peripheral to the system; it was integral to ensuring uniform application of the treaty across all member states. This institutional choice enabled the gradual development of doctrines that reinforced the autonomy and effectiveness of the Community legal order.

The Treaty of Rome also redefined the relationship between international obligations and domestic legal systems. Although the treaty did not explicitly articulate doctrines concerning internal legal effect, its structure presupposed that Community law would operate within national legal orders. Member states undertook to take all appropriate measures to ensure fulfilment of treaty obligations and to abstain from actions that could jeopardize the achievement of their objectives. This obligation implied a duty of internal compliance that went beyond external responsibility under classical international law.

The emergence of supranational law under the Rome framework was further supported by the treaty’s principle of effectiveness. The objectives of the common market could not be achieved if national measures were allowed to neutralize Community rules or delay their application indefinitely. The legal system created by the treaty, therefore, required norms that were uniform, predictable, and resistant to unilateral modification. This functional necessity shaped the evolution of judicial reasoning and reinforced the idea that Community law constituted a distinct legal order rather than a mere aggregation of international commitments.

The birth of supranational law also altered the traditional balance between political discretion and legal constraint. Under the Treaty of Rome, integration was no longer driven solely by diplomatic negotiation or intergovernmental consensus. It was increasingly shaped by legal interpretation, compliance obligations, and institutional procedures. Courts, administrators, and economic actors became participants in the integration process, applying and invoking Community rules in everyday contexts. This diffusion of legal authority marked a qualitative shift in how international norms operated in practice.

In conceptual terms, the Treaty of Rome challenged the classical dichotomy between international and domestic law. It demonstrated that an international agreement could generate a legal order with its own internal logic, institutions, and enforcement mechanisms, while still being rooted in the consent of sovereign states. This hybrid character has had lasting implications for theories of sovereignty, constitutionalism, and legal pluralism in international law.

The significance of the Treaty of Rome in the birth of supranational law, therefore, lies not in any single doctrinal innovation, but in the cumulative effect of its design choices. By combining detailed obligations, permanent institutions, judicial oversight, and a commitment to effectiveness, the treaty created the conditions for a legal system that transcended traditional treaty law. This legacy continues to shape debates on the limits and possibilities of legal integration in an increasingly interdependent world.

VII. Evolution, Amendments, and Systemic Transformation

The Treaty of Rome was not conceived as a static legal instrument but as the foundation of an evolving legal system. Its drafters anticipated change and deliberately designed a framework capable of adaptation without undermining legal continuity. This capacity for evolution explains how the original treaty could sustain successive waves of amendment while preserving its core logic and institutional identity.

One of the most distinctive features of the Treaty of Rome was its conclusion for an unlimited duration. Unlike many post-war agreements tied to specific transitional goals or timeframes, the treaty established a permanent Community. This choice allowed legal obligations to mature over time and created the structural conditions for incremental reform. As economic integration deepened and policy needs expanded, amendments became a mechanism of system development rather than rupture.

The first major phase of transformation occurred through the completion of the common market. Transitional provisions embedded in the treaty gradually gave way to a fully operational customs union and expanded market freedoms. As these objectives were realized, the Community’s legal focus shifted from dismantling barriers to regulating an integrated economic space. This transition marked a systemic change: integration moved from negative obligations, such as the removal of restrictions, toward positive regulatory coordination.

Subsequent treaty revisions extended this trajectory. Institutional reforms strengthened decision-making capacity, expanded the scope of qualified majority voting, and enhanced the role of representative bodies. These changes responded to practical governance challenges generated by deeper integration and enlargement. Importantly, these reforms did not discard the Treaty of Rome’s foundational principles. They recalibrated institutional balances while retaining the commitment to market integration, legal uniformity, and judicial oversight.

Another dimension of systemic transformation involved the expansion of policy competences. Areas initially peripheral or absent from the original treaty framework gradually became subjects of collective action. Social policy, environmental protection, consumer interests, and economic cohesion emerged as integral components of the integration project. This expansion reflected a recognition that a functioning common market generates externalities requiring coordinated regulation. The Treaty of Rome’s open-ended competence structure facilitated this development by allowing new policy fields to be integrated within the existing legal order.

The evolution of the Rome framework also altered the relationship between the Community and its member states. As competences expanded and enforcement mechanisms strengthened, the boundary between national and supranational authority became more complex. Member states increasingly operated within a system of shared governance, where national policies were shaped by collective objectives and legal constraints. This transformation did not eliminate state sovereignty but redefined its exercise within a multilayered legal system.

Systemic transformation was further reinforced by judicial interpretation. The continuous application and interpretation of treaty provisions contributed to legal coherence across time and policy areas. Judicial reasoning ensured that amendments and new competences were integrated consistently with existing principles, preserving the unity of the legal order despite its growing complexity. In this way, the evolution of the Treaty of Rome was not merely political or institutional but also deeply legal.

By the time the European Communities evolved into the contemporary European Union, the Treaty of Rome had already fulfilled its role as a constitutional anchor. Its principles, objectives, and institutional logic continued to inform later treaty structures, even as terminology and policy scope changed. The Rome framework thus exemplifies how an international treaty can undergo profound transformation while maintaining legal continuity.

The evolution of the Treaty of Rome demonstrates that integration through law is a dynamic process. Adaptation, expansion, and reform were not signs of failure but indicators of a system capable of responding to new economic realities and political demands. This capacity for systemic transformation remains one of the treaty’s most enduring contributions to international and regional integration law.

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VIII. Contemporary Relevance and Critical Reassessment

The contemporary relevance of the Treaty of Rome lies in the fact that many of the structural tensions it sought to manage have not disappeared but have intensified. Economic interdependence, regulatory spillovers, and the limits of unilateral state action are more pronounced today than in 1957. The legal framework initiated by the treaty continues to shape how these challenges are addressed, even as its assumptions and methods are increasingly questioned.

One of the treaty’s most enduring contributions is its model of market integration through law. The idea that economic openness must be supported by common rules, institutional supervision, and judicial enforcement remains central to the functioning of the internal market. In this respect, the Treaty of Rome continues to provide the conceptual foundation for regulatory coordination across diverse national systems. At the same time, contemporary debates on industrial policy, strategic autonomy, and economic resilience have exposed tensions between market integration and state intervention that were less visible at the time of the treaty’s adoption.

The Treaty of Rome also remains relevant in discussions on sovereignty and democratic legitimacy. The legal constraints accepted by the founding states have expanded over time as integration deepened. While this has enhanced the effectiveness of collective action, it has also raised concerns about the distance between decision-making processes and national democratic structures. Critics argue that the legal logic of integration has outpaced political consensus, creating a perception of governance driven by legal and technocratic processes rather than democratic choice. These critiques invite a reassessment of how the original balance between supranational authority and national autonomy has evolved.

Another area of contemporary relevance is the treaty’s reliance on economic integration as a pathway to political stability. The Treaty of Rome was grounded in the belief that shared economic interests would gradually foster cohesion and reduce conflict. While this logic has largely succeeded in preventing armed conflict among participating states, it has been less effective in preventing political fragmentation, divergent economic outcomes, and social discontent within the integrated space. Economic integration has generated winners and losers, and the legal framework has struggled at times to respond to these distributive consequences.

The role of judicial authority, rooted in the Treaty of Rome’s institutional design, also invites critical reassessment. Judicial interpretation has been central to ensuring the effectiveness and uniformity of the legal order. However, the expanding influence of courts in shaping policy outcomes has prompted debates about the appropriate limits of judicial power in a system where political accountability remains primarily national. This tension reflects a broader question inherent in the Rome framework: how to reconcile legal effectiveness with democratic legitimacy in a multilevel governance system.

Contemporary challenges such as climate change, digital regulation, migration, and external economic shocks further test the adaptability of the treaty’s original logic. These issues require collective action that extends beyond market integration and often involves value-laden policy choices. The Treaty of Rome did not anticipate many of these challenges directly, but its open-ended structure has allowed the legal system built upon it to expand into new policy domains. The adequacy of this expansion, and the legitimacy of the legal bases used to support it, remain subjects of ongoing debate.

A critical reassessment of the Treaty of Rome, therefore, does not diminish its historical importance. Instead, it highlights the tension between a legal framework designed for gradual economic integration and the demands of contemporary governance. The treaty’s success in creating a durable legal order has also generated expectations that the system must now address issues that go beyond its original economic focus.

In contemporary terms, the Treaty of Rome stands as both a foundation and a challenge. It demonstrates the capacity of law to structure deep cooperation among states, but it also exposes the limits of integration driven primarily by legal and economic mechanisms. Reassessing its relevance today requires acknowledging both its transformative achievements and the structural constraints that now shape debates about the future of integration.

IX. Conclusion: The Treaty of Rome as a Constitutional Moment

The Treaty of Rome occupies a distinctive place in the history of public international law because it marked a constitutional moment rather than a routine act of treaty-making. It did not merely codify cooperation among sovereign states; it established a legal order structured around permanent institutions, binding obligations, and a shared set of objectives capable of shaping state behavior over time. This constitutional quality explains why the treaty continues to inform legal analysis decades after its entry into force.

As a constitutional moment, the Treaty of Rome redefined the function of international agreements. It demonstrated that treaties could serve not only as instruments of coordination but as foundations for governance systems with autonomous normative force. By embedding economic integration within a framework of enforceable law, institutional oversight, and judicial control, the treaty challenged the assumption that sovereignty and legal constraint exist in a zero-sum relationship. Instead, it illustrated how states could pool authority to achieve outcomes that would be unattainable through unilateral action alone.

The treaty’s constitutional significance is also reflected in its durability. Its core principles and institutional architecture have survived successive amendments, enlargements, and policy expansions. While the scope of integration has evolved, the original logic of rule-based cooperation remains intact. This continuity underscores the success of the Rome framework in balancing stability with adaptability, a defining feature of constitutional systems rather than ordinary contractual arrangements.

At the same time, recognizing the Treaty of Rome as a constitutional moment requires acknowledging its limits. The legal structures it created were designed primarily to facilitate economic integration, and subsequent efforts to extend this framework into more politically sensitive areas have generated tension. These challenges do not negate the treaty’s constitutional character but highlight the difficulty of sustaining legitimacy and cohesion as integration deepens and diversifies.

In legal and institutional terms, the Treaty of Rome represents a turning point in the evolution of international governance. It expanded the horizons of what international law could achieve by demonstrating that law, when combined with institutions and long-term commitment, can structure complex forms of cooperation across national boundaries. This insight remains relevant for contemporary efforts to address global and regional challenges that exceed the capacity of individual states.

The enduring legacy of the Treaty of Rome lies in its example. It shows that constitutional moments in international law are not defined by grand declarations but by carefully designed legal structures capable of enduring political change. Its significance rests not only in its historical achievements but in its continued capacity to inform debates about integration, sovereignty, and the role of law in organizing collective action.

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