The enactment of the Indonesian Criminal Code (KUHP) marks a significant reform in the country’s criminal law system. One of the most notable changes is the formal recognition of living law as a source of criminal law. This recognition provides space for the incorporation of local values and indigenous customary wisdom into the national legal system. However, this provision has sparked controversy, particularly due to its potential conflict with the principle of legality and the protection of human rights. In principle, modern criminal law requires that only acts explicitly regulated by legislation can be subject to punishment. Therefore, the application of unwritten norms as a basis for criminal liability poses serious challenges to legal certainty. This study aims to analyze the prospects of applying living law under the new KUHP by examining its formalization, limitations, and implications for the principle of legality and human rights. This research employs a normative juridical and comparative approach, analyzing statutory regulations, legal doctrines, and practices from several other countries. The findings indicate that the implementation of living law can only be carried out in a limited and conditional manner—through formalization via local regulations, judicial oversight, and assurance that customary norms do not contradict the Constitution. If formulated and applied correctly, the recognition of living law can improve access to social justice, strengthen the legitimacy of law, and contribute to building a peaceful and inclusive society within a sustainable legal development framework
Masyhar et al. (Mon,) studied this question.