Appraisals of the various attempts to bring the authors of war crimes to justice after 1918 are univocal: they all resulted in pitiful failure and constituted the scenario of disaster the victorious allies of 1945 were determined to avoid.
The inter-allied special tribunal to judge the Kaiser as foreseen in the Versailles Treaty never materialized. Germany, Turkey and even neutral countries like The Netherlands refused to extradite suspects.
Trials held in Leipzig and Istanbul were largely perceived as making a mockery of justice and the trials in absentia held out of spite in France and Belgium were considered illegitimate by the nations of the defendants and ultimately frustrating by the nations of the victims. The accumulated effect of these failures was the triumph of a culture of impunity, with dramatic consequences during the second World War.
This blighting and widely shared assessment does call for a reassessment. The various attempts to bring war criminals to justice were the result of grassroots initiatives to gather evidence, record testimony and invent ways to challenge standing practice that national states and national armies had the exclusive and sovereign right to bring their own soldiers to trial.
The sheer size of popular involvement in initiatives to collect evidence on crimes in anticipation of legal process turned it, in all belligerent societies, into a weapon of mass documentation.
Neither can these attempts be reduced to the judicial version of nationalist propaganda campaigns denouncing the enemy. Part of the public opinion, of the political leaders and of the judicial profession in Germany and Turkey were sincerely committed to reign in the culture of impunity in which their national armies and their political allies acted and to distance themselves of some of the most heinous crimes committed in their name.
Investigating judges and political leaders in countries that had been exposed to these crimes framed some of their cases in such a way as to seize on what they perceived as overtures on the side of the judiciary of their former enemies and establish a dialogue of shared norms of what constituted humanity, atrocity, war crimes and due legal process.
The attempts were ultimately unsuccessful but they did constitute a crucial and massive attempt to defeat impunity and, in a way, to End All Wars of unlimited recourse to violence.