Analysis of the Implementation of the Principle of Legality in the Enforcement of General Criminal Law in Indonesia

Abstract

Indonesia, as a state governed by law, emphasizes that every criminal act may only be subject to sanctions based on provisions established beforehand. As a result, the principle of legality becomes a fundamental doctrine for ensuring legal certainty, protecting human rights, and preventing arbitrary criminalization. However, the development of modern crimes and the evolving dynamics of legal interpretation pose new challenges to its application, making it necessary to conduct an evaluation to ensure that the principle of legality remains effective as a core pillar of general criminal law enforcement in Indonesia. The objectives of this research are to identify and analyze the application of the principle of legality in the current enforcement of general criminal law in Indonesia, and to examine and analyze the ideal concept for implementing the principle of legality within Indonesia's general criminal law framework.The methodological approach used in the preparation of this thesis is normative juridical research. The research specification is descriptive-analytical. The theories employed include the theory of legal certainty and the theory of progressive law. The findings of this research indicate that the principle of legality remains the primary foundation of general criminal law enforcement in Indonesia because it ensures legal certainty, as regulated in the old Criminal Code (KUHP), the 1945 Constitution, and further reinforced by the 2023 New Criminal Code. Its implementation, however, encounters various challenges, such as ambiguous statutory provisions, the use of analogy by law-enforcement authorities to fill legal gaps, and the emergence of modern forms of crime—such as cybercrime—that evolve more rapidly than the legislative process. The research finds that the recognition of “living law” in Article 2 of Law No. 1 of 2023 represents a compromise between the need for legal certainty and social justice, but still requires strict limitations to avoid undermining the principle of lex certa. A comparative analysis with Korea and Thailand shows that both countries provide stronger protection for defendants through the application of lex mitior, which allows the elimination of punishment even after a decision has obtained permanent legal force, whereas Indonesia still restricts its application to the period before a final judgment is rendered. Jurisprudential studies, such as Supreme Court Decision No. 964 K/Pid/2015, demonstrating the judiciary's role in safeguarding the legality principle through rigorous examination of criminal elements, particularly the element of unlawfulness. The ideal concept for implementing the legality principle requires clearly formulated offenses, consistent prohibition of analogy, and adequate understanding among law-enforcement officers, in line with Satjipto Rahardjo's theory of progressive law, so that the law does not merely operate as written regulations but also promotes justice and societal benefits.