War Crime: What are the rules of War?


By Shani Asokan 

Following the Russian invasion of Ukraine, the term war crime has been increasingly used to describe the atrocities faced by Ukrainians, and has made its way back into international news headlines and discussions. This is not to say that war crimes have not been committed in our recent history; they certainly have, but the term has grabbed more media attention since the start of the invasion.

So what is a war crime? Simply put, a war crime is a violation of the laws of war that gives rise to individual criminal responsibility for actions by combatants such as intentionally killing civilians, torture, killing prisoners of war, wartime sexual violence, genocide and other related crimes. 

However, it took a long time for the laws on war to be ironed out and for war crimes to even be recognised as grave crimes against humanity. 

Early laws and treaties

The first ever trial for a war crime was in 1474. An ad hoc tribunal of the Holy Roman Empire held Peter von Hagenbach, a knight, responsible for the actions of his soldiers who had used excessive military force and thereby committed criminal behaviour. Thought the language used in this tribunal is similar to the way war crimes are defined today, the trial occurred far before any international laws were created.

The first formal statements of the laws of war and war crimes came with The Hague Conventions and the Geneva Conventions. The Hague Conventions were international treaties that were negotiated at the first and second peace conferences held in The Hague, Netherlands, in 1899 and 1907.

The Geneva Conventions are four interrelated treaties, adopted and expanded upon from 1864 and 1949. These four treaties represent a legal framework for the conduct of war under international law. Today, every single member of the United Nations has ratified the conventions and they are universally accepted as international customary law, covering every situation of armed conflict in the world.

However, the conventions also have three Additional Protocols (two from 1977 and one from 2005) that cover international humanitarian law for persons and objects in modern warfare, and these have not been ratified by several states including, the United States, Israel, India, Pakistan, Iraq, and Iran. A reason for this could be that many of these countries have recently engaged in or are currently engaged in armed conflict and they are wary of being held responsible for their actions. While the conventions cover the rights and protections of combatants, the Additional Protocols focus on civilians and victims of conflict.


The First World War brought with it a need for governments to create a code by which war crimes would be defined. The first draft of this code was called the Lieber Code or ‘Instructions for the Government of Armies of the United States in the Field’. Given the length of the second, the first is more commonly used.

Further, following WWI, a small number of German soldiers were tried for alleged war crimes under international law for the first time in what is known as the Leipzig trials in 1921.

However, the modern concept of war crimes was further developed at the Nuremberg Trials, where the definition for war crimes was based on the London Charter that was published in 1945. Also known as the Nuremberg Charter, this document lay down a framework by which the Nuremberg trials were conducted. The Charter included definitions for war crimes, crimes against peace and crimes against humanity. 

The Nuremberg Trials also resulted in the Nuremberg Principles, a set of guidelines created by the International Law Commission of the United Nations to codify the legal principles underlying the trials. These principles and the Charter were the inspiration for the Tokyo Charter that was used in the Tokyo War Crimes Trial (1946) that tried the Empire of Japan for war crimes committed during WWII.


It was not until 2002 that the International Criminal Court, a treaty-based court located in The Hague, came into being. Unlike the ad hoc tribunals of the past, this court was created to be a permanent institution for the prosecution of war crimes, crimes against humanity, and genocide committed on or after the date it was created. 

The jurisdiction of the ICC is covered by the Rome Statute, a treated that serves as the court’s charter. The Rome Statute defines war crimes as grave breaches of the Geneva Conventions such as: wilful killing, or causing great suffering or serious injury to body or health, torture or inhumane treatment, depriving prisoners of war of a fair trial, taking hostages, attacking civilians, humanitarian workers of UN peacekeepers, using child soldiers, using poison weapons and a range of other wrongs. 

To date, several head of state have been charged with war crimes before the ICC. Some examples are the former Serbian President Siobodan Milosevic, former Liberian President Charles G. Taylor and former head of state of Sudan, Omar al-Bashir.

How it works

According to the Rome Statute, for an action to be considered a war crime, it must have two main elements. The first is a contextual element: that the conduct took place in the context of an international or non-international armed conflict. The second is a mental element: that there was both intent and knowledge with regards to the individual act and the contextual element. Unlike genocide or crimes against humanity, war crimes can be committed against both civilians and combatants, depending on the crime. 

When a charge of a war crime is brought before the ICC, it is generally an individual (like the head of state) who is held responsible for the crime as it is considered a crime of individual responsibility. Trials can last months or years, and most war crimes today are punishable by death or long-term imprisonment.