Another student of the international law faculty at Lwów (then called Lemberg, as part of Austria-Hungary), was Hersch Lauterpacht (1897–1960). It was he who inserted the indictment of “crimes against humanity” – murderous acts by a state against individuals, often its own citizens – into the 1945–46 Nuremberg trials. He helped draft many of the speeches of Sir Hartley Shawcross, the chief British prosecutor. These relate to events both in war and peacetime that, as part of a widespread systematic policy by a state, cause large-scale human suffering or death to a civilian population. Unlike war crimes, which can be committed by individuals, crimes against humanity are generally committed by a national organisation, like an army or a police force.

How are war crimes defined?

A third category of indictments that might be applied to Russian activities in Ukraine are ‘war crimes’. These are activities committed specifically against the series of international treaties and declarations that govern the way war is fought. They were adopted at international peace conferences in 1899, 1907, and 1954, held at the Hague, and became known as the Hague Conventions. They relate solely to acts committed by individuals in war and cover a range of atrocities, including killing civilians or prisoners of war, unnecessarily destroying civilian property, and sexual violence. The 1954 convention relates to the protection of cultural property in armed conflict.

War crimes are perhaps the easiest to define, as they run counter to the Hague Conventions just described. Such crimes also contravene the four Conventions and three additional Protocols which complement them, ratified at Geneva at different times, known collectively as the Law of Armed Conflict.

The first Geneva Convention was initiated in 1864 by what is now the International Committee for the Red Cross and Red Crescent (ICRC) and today they provide minimum standards of humane treatment and protection to war’s victims. They cover civilians, prisoners of war (POWs), and soldiers who are wounded or otherwise incapable of fighting. Although being charged with either of the above categories, international lawyers observe a sense that the headline-grabbing charge of genocide is ‘the crime of crimes’, though not set in any law as such.

Thus, when President Zelensky accuses Russia of committing a genocide in his country, he might technically be referring to war crimes, and even crimes against humanity, which nevertheless fall short of legal genocide. This is why, when British prime minister Boris Johnson recently stated that the events in Bucha “do not look far short of genocide,” a Downing Street spokesperson then clarified that “the determination of genocide should rightly be made by a competent court, rather than by the UK government”.

And although initially cautious, US President Joe Biden on 12 April accused Russian forces of committing acts of genocide in Ukraine. He told journalists: “Yes, I called it genocide because it’s become clearer and clearer that Putin is just trying to wipe out the idea of even being Ukrainian.”

When it comes to bringing individuals to trial, with all the difficulties that might ensue in finding and removing someone from the Russian Federation, it is worth remembering that individuals can be tried in absentia. This means they are physically absent during the proceedings. International jurists generally recognise such a situation if the accused is aware of the trial, is in hiding abroad, or if an attorney is assigned to represent them.

Martin Bormann, a Nazi official and Hitler’s private secretary, was tried in absentia and convicted of war crimes and crimes against humanity at the Nuremberg trial of 1946. Changes of government and political will were also responsible for bringing the former Serbian president, Slobodan Milošević (who died during his trial); Bosnian Serb Army chief, General Ratko Mladić; and leader of the Bosnian Serbs, Radovan Karadžić, before the International Criminal Tribunal for the former Yugoslavia (ICTY). When their crimes were committed, there seemed little likelihood of them ever being brought to justice. Eventually, of 161 indicted individuals from that war, 91 were sentenced.