Yatırım tahkiminde zorunluluk ve mücbir sebep savunmaları: Olağanüstü durumların hukuki yansımaları

In today's world, with the rise of complex crises such as economic collapses, pandemics, environmental disasters, political instability, and armed conflicts, it has become inevitable for states to intervene in investor rights in order to protect public interests. The question of to what extent such state interventions can be considered lawful under international law necessitates a closer examination of the boundaries of two key defences: necessity and force majeure. This master's thesis comprehensively examines the role of these two core legal defences that states may invoke in exceptional circumstances under international investment law, particularly in the context of investor-state dispute settlement. The study explores to what extent state responses to sudden crises may justifiably interfere with investor rights in a globalized economic system, and how these interferences can be legally framed under international law. The primary aim of the thesis is to assess the legal nature and function of the necessity and force majeure defences, particularly within the scope of international investment law. It identifies the legal sources of these defences, including CIL and general principles, and examines the strict conditions under which they may be invoked. It further addresses how these defences are interpreted by arbitral tribunals, their interaction with treaty exception clauses, and the challenges and ambiguities they pose in practice. The thesis goes beyond doctrinal analysis to explore the real-world implications of these defences for both host states and foreign investors navigating emergencies. The first part of the thesis provides the legal framework, starting with the general principles of international law and the ILC Articles on State Responsibility. It clarifies the distinction between necessity and force majeure and examines the role of emergency or exception clauses in investment treaties. It also addresses how force majeure and hardship are treated in investment contracts and how public and private law dimensions intersect in such contexts. The second part of the thesis offers a comprehensive analysis of the necessity defence in investor-state dispute settlement, focusing on Article 25 of the ILC Articles. It details each legal requirement, including the "only way" test, the definition of "essential interest," and the non-contribution criterion, and discusses their application in relevant caselaw. Particular emphasis is placed on the Argentina financial crisis cases, Libya conflict cases, and Egypt gas disputes. The thesis critically evaluates the strict application of legal thresholds and debates surrounding proportionality, contribution, and the overlap with treaty-based exceptions. The third part focuses on the force majeure defence, beginning with its legal definition and requirements under CIL, specifically Article 23 of the ILC Articles. It explores how force majeure has been applied in treaty claims, contractual disputes, and mixed cases, as well as how tribunals have treated its invocation. The thesis underscores its rare acceptance in investor-state dispute settlement and outlines the legal and practical challenges limiting its success. The fourth part presents a comparative analysis with commercial arbitration, examining how force majeure and hardship clauses are understood and applied in purely contractual contexts. It contrasts the more flexible and remedial approach in commercial arbitration with the rigid standards in investor-state dispute settlement, identifying key points of divergence and convergence that may inform future reforms. The fifth part provides a thematic analysis of the application of these defences across different types of crises. It discusses public health emergencies like COVID-19, economic and financial collapses, environmental and climate disasters, war, sanctions, and structural inequalities between Global North and South. This section draws on practical examples to assess how tribunals have approached necessity and force majeure in diverse contexts and considers the implications of emerging jurisprudence. The sixth and final analytical part presents reflections and reform proposals, addressing issues such as better treaty drafting, consistency in tribunal reasoning, safeguarding regulatory space for states, and mitigating structural inequities in investment law. It also proposes steps to ensure a more balanced, predictable, and equitable foreign investment protection system in times of crisis. In conclusion, the thesis evaluates the capacity of international investment law to cope with exceptional situations while maintaining a fair balance between state sovereignty and investor protection. Although necessity and force majeure are narrowly defined in law, their inconsistent application and divergent tribunal interpretations limit their effectiveness. As such, the study calls for clearer drafting of treaties, structural investor-state dispute settlement reform, and a more context-sensitive and equitable legal understanding of state conduct in emergencies.