<![CDATA[Natural law theory asserts that true law must be rooted in reason and directed toward the common good (bonum commune). Within this framework, positive law is legitimate only when it is consistent with natural law, which is derived from universal moral principles. In the context of modern democracy, demonstrations constitute a form of popular participation through which people demand changes to legislation. However, not all demonstrations possess moral legitimacy, as mass demands do not always align with objective justice. This article examines how demonstrations can be evaluated from the perspective of natural law by analyzing three cases in Indonesia: the 1998 Reform Movement, opposition to the 2020 Job Creation Law, and pro-abortion demonstrations. The analysis demonstrates a spectrum of moral legitimacy. The 1998 Reform Movement possessed high legitimacy because it pursued objective justice against tyranny. Opposition to the Job Creation Law possessed partial legitimacy because it embodied the value of procedural justice, while also exhibiting weaknesses in proportionality and epistemic foundations. Conversely, pro-abortion demonstrations lack moral legitimacy because they contradict the basic good of life. For legislators, natural law provides moral guidance for evaluating mass demands rationally and based on prudentia legislativa—practical wisdom that guides decision-making in accordance with natural justice. Thus, natural law offers an objective framework that guides the relationship between demonstrations and legislation, ensuring that democracy is not merely procedural but also substantive, upholding human dignity, justice, and universal moral truth.]]>
