Secularization in Constitutional Law: A Philosophical-Legal Inquiry Into the Relationship Between Religion and the State in Indonesian Constitutionalism

Secularization is one of the most decisive processes in the emergence of the modern state and of constitutionalism. This article examines secularization in constitutional law from the standpoint of the philosophy of law, using the FIRAC method, which sets out the legal facts, formulates the issues, identifies the rules and theoretical framework, applies the rules to the facts, and draws conclusions. Three issues are analyzed: the nature of secularization and how it differs from secularism; the influence of secularization on the foundations and structure of modern constitutional law; and Indonesia’s position as a state based on Belief in the One and Only God that is neither a religious state nor a secular state. The analysis shows that Indonesia has followed a distinctive path of partial secularization: institutional differentiation between the state and religious institutions is under way, yet divine values remain recognized as the moral source of the constitution. This distinctiveness produces tensions that are visible in legislation and in Constitutional Court decisions, and it therefore calls for a clear normative framework, including the principle of public reason, the proportionality test, and the protection of the constitutional rights of minorities.