Collective Self-Defence in International Law

2018 Fiscal Year Final Research Report

• Project/Area Number: 26380057
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: International law
• Research Institution: The University of Tokyo
• Principal Investigator: Mori Tadashi 東京大学, 大学院公共政策学連携研究部・教育部, 教授 (90292747)
• Project Period (FY): 2014-04-01 – 2019-03-31
• Keywords: 武力行使禁止原則 / 国際連合憲章 / 自衛権 / 集団的自衛権

Outline of Final Research Achievements

The right of self-defence, which was a focus of the discussion when the New Japanese Legislation for Peace and Security was deliberated by the Diet in 2015, is originally an international law concept, and this study examined it. As a result, it is submitted that there were two major ways of understanding about the right after the United Nations Charter entered into force in 1945; the right was understood according to the one of them by the International Court of Justice in the 1986 Nicaragua case judgment; i.e., the right shall be understood as the one "to assist another country in the exercise of its right of
individual self-defence".

Free Research Field

国際法

Academic Significance and Societal Importance of the Research Achievements

国際法上の集団的自衛権の法的性質に関しては、従来様々な見解が示されてきた。学説、国家実行、国際判決の分析を通してそれを確定したことは、学術上大きな意味がある。また、集団的自衛権は、日本国憲法との関係でも大きな注目を集めており、憲法上の議論をする上でも、国際法上の概念を確定した意味は大きい。さらには、そうした研究結果を踏まえ、平和安全法制における集団的自衛権の行使にかかわる法制について、法的な評価を示すことができた。