When Nazi Germany attacked Poland in 1939 it committed a war crime, codified by the standards established in preparation for the Nuremberg Trials in 1945. Here is a very useful summary of the Nuremberg process (“The Influence of the Nuremberg Trial on International Criminal Law”, edited by Tove Rosen) at the Robert H. Jackson Center (link), and here is a summary of the Nuremberg Trial process provided by the US Holocaust Memorial Museum (link). Useful discussion and definitions are provided by the United Nations Office on Genocide Prevention and the Responsibility to Protect (link). The principles established for the Nuremberg Trials have served as the basis for subsequent war crimes prosecutions since World War II, including the International Criminal Tribunal for the Former Yugoslavia in response to crimes against humanity in Bosnia and the former Yugoslavia, and the International Criminal Tribunal for Rwanda following the genocide in Rwanda.
The key charges to be considered in the Nuremberg Trials included these:
The crimes hereinafter set out are punishable as crimes under international law:
1. Crimes Against Peace:
a. Planning, preparation, initiation or waging of a war of aggression or a war in violation of international treaties, agreements or assurances;
2. War Crimes:
Violations of the laws or customs of war which include, but are not limited to, murder, ill-treatment or deportation to slave- labor or for any other purpose of civilian population of or in occupied territory, murder or ill-treatment of prisoners of war, of persons on the seas, killing of hostages, plunder of public or private property, wanton destruction of cities, towns, or villages, or devastation not justified by military necessity.
3. Crimes Against Humanity:
Murder, extermination, enslavement, deportation and other inhuman acts done against any civilian population, or persecutions on political, racial or religious grounds, when such acts are done or such persecutions are carried on in execution of or in connection with any crime against peace or any war crime.
The first charge is “initiating or waging of a war of aggression”. It is perfectly evident that this phrase describes Russia’s fullscale invasion and assault on Ukraine perfectly. War crime #1, planning and waging a war of aggression, should be immediately pursued against the Russian state, its leaders, and its military commanders, by the appropriate international tribunal.
The category of misconduct referred to in clause 2 is more complex. But evidence from numerous cities in Ukraine supports application of this article to Russia’s military conduct as well. The fact of “murder, ill-treatment, or deportation to slave labor … of civilian population” appears to be occurring through the use of bombs, rockets, and artillery against city centers, targeting civilians, and the apparent deliberate killings of refugees and news reporters by Russian soldiers and aircraft appear to be documented as well. “Wanton destruction of cities, towns, or villages, or devastation not justified by military necessity” is clearly taking place as well. The videos currently available of apartment buildings ablaze after rocket, shell, and bomb attacks seem to provide prima facie evidence of “wanton destruction of cities” as mentioned in article 2. The kidnapping of mayors of several Ukraine cities possibly fall under this article as crimes as well.
Clause 3 involves “genocide” and mass crimes against human beings, when based on “political, racial or religious grounds”. The fact that Russian attacks on almost all of Ukraine’s largest cities have led to massive refugee movements (currently more than four million displaced persons and refugees) suggests “ethnic cleansing” — an effort to push out of Ukraine’s territory the segment of Ukraine’s population that is most unwilling to accept Russia’s hegemony and domination.
Two important principles were codified in 1950 to reflect the legal practice of the Nuremberg Trials: the principle of the legal responsibility of heads of state and the invalidity of the defense of “following orders”.
The fact that a person who committed an act which constitutes a crime under international law acted as Head of State or responsible Government official does not relieve him from responsibility under international law.
The fact that a person acted pursuant to order of his government or of a superior does not relieve him from responsibility under international law, provided a moral choice was in fact possible to him.
These principles imply that the individual leaders of the Russian war of aggression against Ukraine are personally vulnerable to charges of war crimes. Principle III explicitly declares that the head of state (Vladimir Putin) is appropriately subject to charges of war crimes under international law. Perhaps more importantly, Principle IV implies that military commanders themselves are liable to charges based on the crime of waging aggressive war. This strongly suggests that military commanders need to be considering their own liability for their actions in Ukraine.