Jus ad Bellum is a fundamental principle of international law dealing with when a state has a legal and moral right to initiate the use of force. Meaning “right to go to war,” it forms part of the broader Just War Theory and is distinguished from jus in bello, which governs the conduct of warfare. Under the modern UN system, the general use of force is prohibited, subject to limited exceptions such as self-defence under Article 51 of the UN Charter and UN Security Council authorization.
This article explains the legal structure, Article 2(4), self-defence, Security Council authorization, humanitarian intervention, Responsibility to Protect (R2P), pre-emptive and preventive self-defence, classical Just War criteria, necessity, proportionality and imminence. It also examines contemporary challenges arising from terrorism, cyber warfare, drone warfare and hybrid warfare, making the topic particularly relevant to International Law, International Relations, Political Science, UPSC, UGC-NET and Competitive Examinations.
Author: Darshita Neeraj
Senior Researcher,
Mudita Learning and Knowledge Private Limited
Email: info@muditabooks.com
Date of post: 11.08.2026
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