Research on the Principles of Necessity and Proportionality on the Use of Force against terrorism

2018 Fiscal Year Final Research Report

• Project/Area Number: 15K16931
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: International law
• Research Institution: Tokyo International University
• Principal Investigator: Nemoto Kazuyuki 東京国際大学, 国際関係学部, 准教授 (40453617)
• Project Period (FY): 2015-04-01 – 2019-03-31
• Keywords: 武力行使 / 自衛権 / 必要性原則 / 均衡性原則 / 国際連合

Outline of Final Research Achievements

This research clarified that, on the necessity principle, besides the exhaustion of or non-alternative means, in the case for the territorial state to harbor terrorists actively or not to have the will and ability to prevent the activities of the terrorist, the necessity principle is satisfied. Second points of result of this research has been led from the detail examinations of official statement of some governments and the judgement of international courts in cases which takes on the matter of the legality of the use of force. On the proportionality principle, even in the evaluation of its legality of the use of force under jus ad bellum, forces under the right of self defense with targeting limited to military objectives as a means or methods in the realm of jus in bello are considered to be satisfied. Therefore, This research successfully made it clear that in the field of international law of self defense there are some interactions between jus ad bellum and jus in bello.

Free Research Field

国際法学

Academic Significance and Societal Importance of the Research Achievements

これまで「自衛権」という無限のヴェイルに包含させてきた多様な武力行使事例を、先行する原因行為の「時間的位相」（武力復仇や累積理論、先制自衛）と「主体的位相」（国家対国家の自衛と非国家主体対国家の自衛）、「場所的位相（内戦、越境武力行使）」という基軸に従い整理することで、必要性・均衡性原則の評価基準を体系化し，とりわけ，必要性・均衡性原則が，それぞれの位相ごとに機能的に評価基準が細分化されており，武力行使の制限規範として機能することを明らかにした点に学術的意義を見出すことができる。この研究は，自衛権の開始要件である「武力攻撃」の充足の判断が困難な先制的自衛権においても，制限規範の役割を担う。