One of the worst atrocity crime stories of recent decades has barely registered in the world's collective conscience. We remember and acknowledge the shame of Cambodia, Rwanda, Bosnia and Darfur. We agonise about the failure to halt the atrocities in Syria. But, at least until now, the world has paid almost no attention to war crimes and crimes against humanity comparable in their savagery to any of these: the killing fields of Sri Lanka in 2009.
Three years ago, in the bloody endgame of the Sri Lankan government's war against the separatist Tamil Tigers, some 300,000 civilians became trapped between the advancing army and the last rebel fighters in a tiny strip of land in the northeast.
With both sides showing no restraint, at least 10,000 civilians - possibly as many as 40,000 - died in the carnage that followed, as a result of indiscriminate army shelling, rebel gunfire, and denial of food and medical supplies.
The lack of outrage mainly reflects the government's success in embedding in the minds of policymakers and public an alternative narrative: that what occurred was the defeat, by necessary means, of a terrorist insurrection.
The other key reason behind the world's silence is that the Sri Lankan government was relentless in banning independent observers from reporting on its actions. And this problem was compounded by the timidity of in-country UN officials in communicating such information as they had.
President Mahinda Rajapaksa's government claimed throughout, and still does, that it maintained a "zero civilian casualties" policy. Officials argued that no heavy artillery fire was ever directed at civilians or hospitals, that any collateral injury to civilians was minimal, and that they fully respected international law.
But that narrative is now being picked apart in a series of recent publications, notably the report last year of a UN panel of experts, and in two new books.
Nobody underplays the Tigers' contribution to the 2009 savagery; but, with their leaders all dead, international attention should now be focused on holding the government accountable for its failure to protect its own people.
Real international pressure is at last being placed on the government, most significantly by the much maligned UN Human Rights Council in Geneva, which will consider Sri Lanka's response next March.
Moral failure is easier to live with if we can pretend it never happened. But mass atrocity crimes did happen in Sri Lanka, there was moral default all around, and if we do not learn from this past, we will indeed be condemned to repeat it.
Gareth Evans, former foreign minister of Australia, co-chairs the Global Centre for the Responsibility to Protect. Copyright: Project Syndicate