This study seeks to re-articulate the legal status of warships and the structure of their exercise of jurisdiction within the framework of peacetime international law. Through a systematic assessment of international normative developments and state p...
This study seeks to re-articulate the legal status of warships and the structure of their exercise of jurisdiction within the framework of peacetime international law. Through a systematic assessment of international normative developments and state practice, it anticipates legal issues that may arise in adjacent seas and proposes measures to employ warships and naval power actively and in conformity with international law for the protection of national security and national interests. To this end, the research emphasizes the combination of normative analysis and operational empirics, identifies linkages between legal norms and operational procedures, and proposes improvements capable of institutionalization. The scope of analysis is confined to warships directly connected to the exercise of jurisdiction under international law. Although non-commercial government vessels possess certain immunities and prerogatives analogous to those of warships, the focus on warships is justified on the grounds of policy relevance, given that warships combine, in their historical formation and operational use, the dual character of instruments of war with the practical prospect of deployment in peacetime law-enforcement missions. Methodologically, this study adopts the Multi-Level Perspective (MLP), commonly employed in analyses of technological and social change, as an analytical framework for legal scholarship to comprehend shifts in the warship-employment paradigm in a multidimensional manner. This framework explains the dynamics of change through non-linear interactions among three tiers: the landscape, the socio-technical regime, and niche innovations. In this application, the landscape corresponds to the broadening of security pressures involving economic, energy, and environmental security. The socio-technical regime corresponds to the stable international maritime legal order centered on the United Nations Convention on the Law of the Sea (UNCLOS) together with national legal systems. Niche innovations correspond to emerging enforcement practices such as maritime interdiction operations, the Proliferation Security Initiative, and bilateral ship-boarding agreements. Particular attention is given to structural tensions between foundational rules of the existing order, including the exclusivity of flag-state jurisdiction and the freedom of navigation on the high seas, and these niche innovations. The tensions materialize in debates over the legitimacy of maritime interdiction operations, the boundary between law-enforcement and military operations, limits on the use of force, and the protection of the human rights of detained seafarers. Interpretations and standards that emerge in response provide the logical basis for subsequent domestic institutional design. In parallel, the study triangulates relevant international norms, the domestic laws and policies of major maritime powers, and actual jurisdictional cases. This triangulation reveals points of contact between norms and practice and strengthens the explanatory account of jurisdictional mechanisms. The structure of the research proceeds sequentially from theoretical foundations to application and institutionalization. First, a systematic clarification of the concept and character of state jurisdiction under international law confirms the basic architecture of the maritime order, in which prescriptive and enforcement jurisdiction are distinguished and functional jurisdiction is apportioned under the treaty framework. The analysis then traces the historical evolution of the definition and status of warships, reviews criteria that distinguish them from non-commercial government vessels, and undertakes a comparative assessment of domestic legal frameworks and operational practices among major maritime powers. It further examines international cases in which warships have exercised jurisdiction in order to identify gaps and limits between normative authority and actual enforcement. Building on that foundation, the study selects core issues that arise during jurisdictional operations for in-depth analysis and concludes by proposing institutional design through domestic application and policy measures. One core issue concerns maritime interdiction operations (MIO). MIO constitute a comprehensive operational concept in which a warship undertakes phased measures in a designated sea area, including stop, boarding, search, seizure, and detention. Since the end of the Cold War, the rise of non-state actors and non-traditional threats has tied MIO closely to peacetime operations and diversified their scope and purpose. Neither international treaties nor the law of naval warfare formally define MIO as a legal term of art. The concept instead appears through state doctrinal manuals, guidance issued by international organizations, and Security Council resolutions. NATO operational manuals and doctrines provide an operational framework for visit and search that includes control of entry and exit with respect to particular states or regions. This study examines how such operational concepts shape legal interpretation when they are coupled with prerequisites for legal justification, limits of authority, and procedural control mechanisms. In particular, the study analyzes this issue with focus on the legitimacy of warships' exercise of jurisdiction and the debate over the boundary between military operations and law-enforcement operations. A further core issue concerns whether the use of force by warships during the exercise of jurisdiction violates the principle of the prohibition of the use of force under the United Nations Charter. This study elucidates the legal significance of the use of force and threat of force, and through the introduction of criteria regarding purpose, context, and means as core issues related to force in the exercise of jurisdiction, seeks to distinguish between warship operations that constitute law-enforcement operations and those that constitute military operations. The third core issue is enforcement measures in response to illegal fishing and piracy. The study identifies limits and standards of enforcement measures that warships may exercise, reviews procedural controls and post-action responsibility systems, compares state and regional response models, and analyzes the problems of evidence standards and data governance to identify legal prerequisites necessary to ensure coherence between effective enforcement and subsequent judicial proceedings. The protection of human rights and the attribution of responsibility during vessel seizure present a representative challenge of normative integration. UNCLOS affirms exclusive flag-state jurisdiction on the high seas as well as the immunities of warships and non-commercial government ships. At the same time, international human rights law presupposes that states bear human-rights obligations toward individuals under their effective control even outside national territory. In practice, once a foreign merchant vessel is stopped, boarded, and diverted, its crew remain under the flag state's formal jurisdiction while falling under the de facto control of the seizing state. At that juncture, complex issues arise regarding attribution of responsibility, adjudicatory jurisdiction, proof, and enforcement. Limits on the use of force and on detention in maritime law-enforcement are framed jointly by the law of the sea and international human rights law. The principles of reasonableness, necessity, proportionality, and minimization of harm operate in a mutually reinforcing manner through decisions and guidelines. Through such analysis, this study emphasizes the importance of procedural standardization for evidence management and clarification of responsibility attribution. By documenting step-by-step actions—identification, warning, heave-to, boarding, and securing—and establishing continuous management systems for collection and preservation of video and audio records, navigational data, and communications at each phase, evidentiary value can be enhanced in subsequent criminal proceedings and international cooperation. The study proposes the design of electronic handover records and standardized documentation procedures, drawing on chain-of-custody procedures outlined in maritime crime investigation and prosecution manuals. To address cyber threats and vulnerabilities in remote-control infrastructure, rules of engagement should mandate the segregation of operational technology and information technology across vessels, shore facilities, and relay links, to incident-response procedures, and to legal limits on active interaction with third-party communications networks. Responding to new and emerging threats requires dedicated procedural designs and legal bases. The recent repeated use of unmanned surface vessels and unmanned underwater vehicles in disputed and littoral waters has led to their recognition as vectors of risk in both military conflict and peacetime law-enforcement contexts. These instances indicate that each phase of interaction——detection and tracking, identification, heave-to, boarding, and detention—requires distinct criteria, procedures, security measures, and adjusted responsibility-—allocation structures tailored to the characteristics of remote platforms. Coherent linkage between international guidance and domestic regulation is therefore necessary. From the perspective of domestic application and institutionalization, the study proposes the following designs. First, the study proposes: (1) the codification of criteria for determining the scope of maritime interdiction operations; (2) the normative elevation of principles regarding the use of force; and (3) the establishment of obligations for evidence collection and record-keeping as well as post-action review procedures. Second, the study proposes the enactment of basic legislation on warship jurisdiction, which would: (1) create domestic legal foundations; (2) normalize authority and procedures by maritime zone; and (3) codify human rights guarantees, interagency coordination, and international cooperation mechanisms. Third, through legal and institutional refinement of regulations by type of warship jurisdictional operations, the study proposes the development of specific regulations for responses to illegal fishing, piracy and armed robbery, and technology-based threats. Fourth, in introducing enforcement governance, the study proposes the establishment of integrated command and information-sharing systems among civilian, governmental, military, and law-enforcement authorities, the institutionalization of post-action reviews and record management, and the linkage of international reporting and cooperation channels to domestic procedures. The scholarly contributions can be articulated in three dimensions. First, by presenting an integrated analytical framework for comprehending the status of warships and their exercise of jurisdiction within the structure of peacetime international law, the study systematizes previously fragmented discourse. Second, by triangulating international norms, state practice, and real-world cases, it establishes a verification pathway to assess the coherence between international norms and state practice. Third, by proposing domestic institutional design and policy measures, it concretizes improvements that can be executed in the field. Furthermore, by diagnosing collision points between niche innovations and the regime and by indicating directions for regime reconfiguration in response to new environmental pressures, the study can serve as a benchmark for future legislation and the refinement of command architectures. In sum, this study re-articulates the legal status of warships and their exercise of jurisdiction within peacetime international law, analyzes core issues encompassing maritime interdiction operations, the use of force and threats thereof, responses to illegal fishing and piracy, protection of human rights, evidence management, responses to unmanned platforms, and proposes measures to strengthen predictability and accountability through domestic standard operating procedures and legal design. These proposals can enhance the legal and operational capacity to exercise jurisdiction in the waters adjacent to national territory and contribute a legal and institutional foundation for the protection of national security and national interests.
keywords : Exercise of Jurisdiction by Warships, Maritime Interdiction Operations (MIO), Peacetime International Law, Principles on the Use of Force, Distinction between Law Enforcement and Military Operations