Reconstructing Legality in a Plural Legal System: Living Law and Customary Criminal Law Under Indonesia’s New Criminal Code

Introduction: The recognition of living law under Indonesia’s new Criminal Code challenges the conventional understanding of the legality principle, which traditionally requires criminal liability to be based on predetermined written law. The challenge is particularly significant in Indonesia’s plural legal order, where customary norms continue to operate alongside state law. Purposes of the Research: This study aims to reconstruct the principle of legality by examining the normative position of living law and customary criminal law under Law No. 1 of 2023 concerning the Criminal Code. It specifically examines how legal certainty, substantive justice, constitutional rights, and cultural legitimacy can be reconciled. Methods of the Research: This study employs normative legal research using statutory, conceptual, philosophical, and comparative approaches. Primary legal materials consist of Law No. 1 of 2023 and its implementing regulations, while secondary materials include scholarly literature on legality, living law, legal pluralism, and customary criminal law. The materials are analyzed qualitatively and prescriptively. Results of the Research: The study finds that living law does not abolish the legality principle but modifies its operation within a constitutionally bounded plural legal framework. Customary criminal norms may function as a limited source of criminal liability only when their existence, territorial applicability, normative content, and compatibility with constitutional and human-rights standards are established. The study proposes a bounded legality model that combines formal legality, validated living law, judicial scrutiny, and institutional safeguards. Conclusion: The reconstruction therefore requires not unrestricted judicial recognition of customary norms, but a controlled integration of living law that preserves legal certainty while accommodating legitimate customary values.