The Instant Customary Rule in Contemporary International Law

This study explores the concept of instant customary rules in contemporary international law, a modern legal phenomenon that reflects the adaptability of customary international law to the rapidly evolving dynamics of international relations. Unlike traditional customary norms, which require sustained and repetitive state practice over an extended period, the instantaneous norm can arise swiftly, sometimes even with opinio juris (the belief in a legal obligation) preceding actual practice. The research aims to clarify the conceptual framework of instant customary law, highlight its distinct characteristics, and analyze the legal foundations for its formation. It also addresses the challenges related to its acceptance, evidentiary requirements, and practical application. Moreover, the study examines the perspectives of international legal scholars, judicial bodies, and international organizations on the validity of such rules, supported by practical examples in emerging fields such as environmental protection, outer space exploration, and the establishment of exclusive economic zones. The study concludes that instant customary rules embody the flexibility of international law and its ability to respond promptly to global developments while maintaining legal binding force, thereby strengthening the effectiveness of the international legal system.