Jus in Bello Jus ad Bellum

By | October 2, 2019
Jus in Bello Jus ad Bellum

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Jus ad Bellum a legal maxim is defined as the reasons cited by countries which make the restoration to war an absolute necessity. Jus in Bello, on the other hand, is the maxim used for the acts which are legal during the time of war.

Introduction and Meaning

Since ancient times the rulers have resorted to war for the expansion of their kingdom. Not until the two devastating wars of the 20th Century did the international community understand the relevance of formulation of wars relating to proper conduct at the time of war.

Jus ad Bellum a legal maxim is defined as the reasons cited by countries which make the restoration to war an absolute necessity. The Charter of the League of Nations considered restoration of war as a method of settlement of disputes. Gradually the restoration to armed force was prohibited, ultimately culminating with the adoption of the UN Charter.

With the success of the pacific settlement of disputes, the scope and extent of Jus ad Bellum became constricted. In the contemporary world, it is limited to the practice of self-defence (under Article 51 of the Charter) and collective security operations (Chapter VII of the Charter).

Jus in Bello, on the other hand, is the maxim used for the acts which are legal during the time of war. It is more commonly referred to as International Humanitarian Law (IHL).  Previously, in India, there were customs which served as laws regulating proper conduct at the war ground. The Indians were not allowed to resort to war after sunset, or the sounding of the ‘sankh’.

There were rules preventing stabbing at the back of the soldier. The main ideology behind this was the prevention of unfair methods during warfare.  In contemporary times the examples of Jus in Bello are sparing people not directly involved in hostilities and limiting the violence to the amount absolutely necessary to achieve the aim of the conflict.

Just War Doctrine – Hugo Grotius

The philosophy of ‘Just War’ by the Hugo Grotius is of relevance in understanding the concepts and relationship of Jus in Bello and Jus ad Bellum. The word ‘just’ is used as a pun to establish ethical standards in war. Just cause for restoration to war is Jus ad Bellum and conducting in a just manner while in war is Jus in Bello. Thus according to Hugo Grotius, Just War is one which is for the right cause and which employs proper ethical practices.

Cristopher Greenhood in his paper: ‘The Relationship Between Jus ad Bellum and Jus in Bello’ considers that two “can and should be regarded as distinct from another”.

The concept of just is however very subjective with respect of various groups raging war. In this context, the meaning of the term just becomes increasingly ambiguous. What would be ‘just’ for a terrorist organisation like ISIS might not be just for a soldier. In the 1949 Geneva Conventions and the First Additional Protocol of 1977 (common Article 1), it is mentioned that states undertake to respect and ensure respect for IHL “in all circumstances”.

Quite recently, the Statute of the International Criminal Court clearly created a distinction between aggression and war crimes. Aggression is a blatant violation of Jus ad Bellum and war crimes are the crimes in the course of the war. The international law considers Jus in Bello and Jus ad Bellum in contravention to one another.

The rationale behind the enforcement of ethical standards of warfare and moral conduct is to prevent using war as a tool to destruction. In the age of the rise of human rights war is a deterrent to society. The concept of war should be abolished both ideologically and philosophically. There can be no ‘just war’ because war is never just except for powerful.


The article was contributed by Avishikta Chattopadhyay

Author: Mayank Shekhar

Mayank is a student at Faculty of Law, Delhi University. Under his leadership, Legal Bites has been researching and developing resources through blogging, educational resources, competitions, and seminars.