A change of strategy and security system of a state is a matter that certainly happens. The strategy and security system of a state are not static matters, but they are dynamic with a change of strategy and security system are influenced mostly by the dynamics of strategic environment which keep developing and changing. National security is an element embedded from a purpose of state governance. As the government of state, the government needs an arrangement of national security regarding the authority system of institutions that has a role in the attempt to reach national security. This study is focused to analyze the ratio legis or the aim and purpose of the created authority arrangement in the fields of defense and security of state in National security system based on instrument of laws and regulations regarding defense and security. The approaches used in this study are: historical, conceptual, regulations, comparative and philosophical. This study uses primary legal material and secondary legal material. On the other hand, analysis on the root of problems and the legal materials were conducted in prescriptive analytic, which provides thinking to answer root of problems in the study. The result of this study shows that there is no regulation regarding comprehensive defense and security which regulate national security that is in accordance with national security system as intended in the Preamble of 1945 Constitution of Indonesia. The regulations are still partial and sectorial; it has not been able to give the strong basis; it is not clear and strict in decide the actors in overcoming national security; and even cause obscurity related to the implementation of defense and security.
