( CNN ) Fifty years ago in Frankfurt , German prosecutors tried 22 former Nazi SS soldiers at Auschwitz in what remains the most famous Holocaust trial staged in Germany . At the time , Fritz Bauer , the German-Jewish attorney general of Hessen , expressed the simple hope that `` sooner or later , one of the accused would step forward and say : 'What took place -- it was horrific , I 'm sorry . ' Then the entire world would exhale , as would all the survivors of those killed at Auschwitz , and the air would be cleared . '' Sadly , Bauer observed , `` it has not been uttered , nor will it be . '' The refusal of perpetrators to own up to their guilt remains one of the most disappointing aspects of Holocaust trials . John Demjanjuk , whose conviction by a Munich court in 2011 established the precedent that has now made possible the trial of Oskar Gröning , remained defiantly silent during his 18-month trial , never so much as breathing a word of acknowledgment or remorse . Over the years , some defendants have acknowledged knowing of the exterminations , but have insisted that they played no role . Those who acknowledged participating in the killing insisted that they did so out of fear of life or limb . Over the years , an extraordinary research effort was dedicated to exploring the claim that SS men had engaged in extermination out of duress . The results were astonishing : Investigators and historians failed to uncover so much as a single instance in which a German officer or NCO had been executed or even severely punished for opting out of genocide . Not one . These evasions and lies were often effective , as many German trials of Holocaust perpetrators ended either in light sentences or outright acquittal . And even when a trial ended in a conviction , what was missing was any sense of moral reckoning , an acknowledgment on the part of the accused of the perversity of genocide . Fritz Bauer can now exhale . On April 21 , on the opening day of his trial in Lüneburg , where he stands accused of complicity in the murder of 300,000 Jews during his service at Auschwitz , the 93-year-old Gröning faced the court and acknowledged , `` It is beyond question that I am morally complicit . This moral guilt I acknowledge here , before the victims , with regret and humility . '' If nothing else comes from the trial , that statement alone justifies the undertaking . Of course , in acknowledging his moral complicity , Gröning fell short of confessing legal guilt . Indeed , for years he has insisted in his innocence as a matter of law , arguing , in an interview with Der Spiegel in 2005 , that he had been no more than a `` cog in the gears . '' At Auschwitz , Gröning was responsible for inspecting the luggage of deportees to the camp -- most of whom were gassed within hours of their arrival -- for banknotes that would be carefully counted and sent to Berlin . In performing this task , Gröning insists that he never engaged in cruel , murderous or sadistic acts -- a claim that we can probably accept as true . But does this relieve him of criminal liability ? For decades German courts held that mere service as a concentration camp -- in the absence of evidence of a personal act of killing -- constituted no crime under German law . In 2011 , the Demjanjuk conviction changed that . In convicting Demjanjuk as an accessory to the murder of 28,000 Jews at the Sobibor death camp , the Munich court concluded that death camp guards , regardless of how they had conducted themselves , had to be accessories to murder , because that was their job . It was a crucial breakthrough , because it recognized that mass killing is not a personal act of evil but an exterminatory process . When it comes to factory-like genocide , guilt is not to be measured by acts of cruelty or nastiness ; guilt follows function . Convicting under that theory was the great accomplishment of the Munich court . By this standard , Gröning 's truthful claim that he was no more than `` a cog '' constitutes an admission of guilt . This does not mean that Gröning deserves the same measure of punishment as an SS sadist . In fact , it 's not clear that he deserves any punishment besides the symbolic gesture of conviction . But without the court 's conviction , Gröning 's important acceptance of moral guilt will remain incomplete . The significance of Gröning 's trial can be measured in one final way . Many have observed that it coincides with the 70th anniversary of the end of World War II . But it also coincides with an anniversary of a different sort . April 24 marks the day that millions mourn the killing of hundreds of thousands of Armenians by the Ottomans during World War I , an event many have described as genocide . And yet the Turkish nation itself remains in denial of the mass killings that unfolded a hundred years ago . With that in mind , Gröning 's trial reminds us of other mass atrocities that still await their moment of moral and legal reckoning .
Oskar Gröning is on trial over his alleged role in deaths at Auschwitz . Lawrence Douglas : Other mass atrocities still await moment of moral reckoning .