State sovereignty is a prerogative right that must be maintained as a priority, especially in Indonesia is archipelagic geography. This presents a significant challenge in maintaining sovereignty over the Natuna Islands and Lingga Islands in Riau Islands Province, Indonesia. This area has been the subject of international conflict, particularly concerning China's claim under the Nine-Dash Line, which the Chinese government justifies with historical arguments and past governmental decisions. However, this claim lacks a valid legal basis under international law, including the United Nations Convention on the Law of the Sea (UNCLOS) 1982, which defines international maritime boundaries. The conflict began to escalate in 2016 following the arrest of three Chinese fishermen involved in large-scale illegal fishing, an act supported by the Chinese government. In response, the Indonesian government took measures to assert its sovereignty by strengthening military security, engaging in diplomatic efforts with ASEAN member states, and conducting best practice studies to potentially bring the Natuna Sea sovereignty dispute before the International Court of Justice. Indonesia's sovereignty over the Natuna Sea is firmly supported by the Djuanda Declaration and the 1982 UNCLOS Agreement. This study aims to analyze the Natuna conflict using a Normative Law and Military approach as the primary strategies to resolve disputes over the Natuna Sea.

The DI/TII social movement, which began on August 7, 1949, emerged as a result of socio-political tensions, particularly resistance to the Reorganization and Rationalization (Rera) policy. This movement aimed to establish an Islamic state in Indonesia and arose as a reaction to government policies perceived as inconsistent with Islamic principles. Discontent among former TNI soldiers and local militias due to the Rera policy fueled the movement, with many of these disillusioned individuals joining DI/TII. On February 10–11, 1948, Sekarmadji Maridjan Kartosuwiryo and Raden Oni organized a conference of Islamic leaders, during which the idea of forming the Islamic State of Indonesia (Negara Islam Indonesia, NII) was introduced. Kartosuwiryo declared himself the Grand Imam of the Islamic State of Indonesia. The widespread and massive expansion of this movement increasingly disrupted society, as it involved acts of extortion and armed resistance, creating unrest and opposition among the population. In response, the Indonesian government adopted a responsive legal approach, reflected in measures such as the enactment of the Emergency Law of 1949 and the re-adoption of the 1945 Constitution, which included restrictions in Article 28J(2). Various efforts were undertaken to address the situation, including the deployment of military operations to suppress the rebellion and restore stability.