This paper focuses on the discretionary powers given by Japanese law to the judges in lawsuits about the deportation of undocumented aliens who stayed for long in Japan. Despite the established administrative standards for considering whether undocumented aliens are to be deported or given amnesty, there is a vagueness about the whole process.
At the level of administrative law, the problem lies with the discretion controlling method of the administrative agency. To resolve this problem, it is necessary that judges exercise their discretion based on constitutional principles and values. However, the constitutional base of this issue is not so obvious. To analyze the carious elements with regard to immigration laws and territory, understanding of the concept of “nation” in the constitutional law is a prerequisite. However, referring to judicial precedents, the theory of academic constitutional law is insufficient to understand the concept of “obligation” which is contained in the concept of nation.
Referring to the political obligation theories analyzed by previous studies on philosophy of law and political philosophy, and utilizing the hints given by these theories, the author first interpreted the concept of nation from the viewpoint of obligation, and suggested the possibility of bridging the gap between obligation theory and right theory using the concept of status. Additionally, referring to the concept of obligation of nation and state, the author re-interpreted the system of immigration control law and individual amnesty, as a supplemental obligation undertaking system in the nation state adopting jus sanguinis. The author hopes that this study will shed more light on the discourse about the concept of constitutional
nation and make the discussion more lively.