The folkloric atmosphere suggested by a title like Once Upon a Time in Iraq a landmark documentary on the long catastrophe of Saddam’s atrocities, the US-led invasion in 2003, insurgency, civil war and the rise of ISIS, belies the straightforward style of the film-making – interviewees simply tell their stories, cut with contemporary footage filmed for the most part on camcorders and mobile phones.

Where, perhaps, the inspiration for the title comes from is the curious way the stories told on screen assume the monumental qualities of a great fiction, both in their archetypal structure – the star soldier destined to be a general who, like Colonel Kurtz, goes mad in the acute conditions of conflict, the sole survivor of a massacre who escapes by playing dead, the soldier who does not make it back from ‘the last patrol’ – and in the style in which they are told.

The interviewees speak with an eloquence and the disturbing moral clarity often found in those who have lived in warzones, a special kind of insight gleaned from close contact with what French writer Simone Weil called ‘that X that turns anybody who is subjected to it into a thing.’ Indeed, in Once Upon a Time we are confronted again and again, like a Goya print in motion, with the material devastation of warfare – smashed buildings, smashed homes, and limbs, bodies and a long tail of mental devastation.

This documentary is quite different in this sense to the The Vietnam War, directed by Ken Burns. His ‘epic’ series is broadcast over 10 episodes, each is an hour and a half (Once Upon a Time is just five hours long) and is very heavy on narrative, with a revolving cast of Vietnamese and American combatants and observers. The project, like its title, is portrayed as definitive, which leaves it vulnerable to the charge of hypocrisy (Burns is drawn more consistently to the American side of the story than the Vietnamese); Once Upon a Time, by contrast, is light on detail. Events are sketched out; ordinary Iraqis, servicemen and journalists who were there on the ground make up the essential drama.

I am reminded of Claude Lanzmann, director of the Holocaust documentary Shoah, who wrote of ‘the obscenity of the project of understanding’. To explain, rather than to simply observe traumatic events, for Lanzmann, was connected to a deep human need ‘to engender harmoniously’ what should be left broken. It ended, for him, in ‘an absurd dream of nonviolence’. This obscenity is felt on some level in a film like Schindler’s List, as if there could be a list of ‘saved’ that somehow redeems the tragedy of the whole.

In that spirit, in Once Upon a Time we are invited to not avert our eyes from the long catastrophe of Iraq and to leave grand judgments about the rights and wrongs of intervention and dictatorship to one side. In the veteran war reporter Anthony Loyd’s memoir of his time in Bosnia, he comments: ‘All the crap you hear talked about Bosnia … pull up those bones like a Meccano set and make whatever you want of them … [but] you have to relinquish a lot until the reckoning comes … examine it and realize it’s just the relationship between yourself, killers and victims that counts… [you] discover you are a hybrid.’

That is not to say that this ‘reckoning’ is straightforward in Once Upon a Time. In one illuminating moment, one of the interviewees is asked by the director James Bluemel, ‘Can you tell me what happened to your brother?’. He replies, smiling, ‘Do I have to?’. ‘Of course you don’t have to,’ responds Bluemel. ‘I hate that moment…’. He then continues with his story. The interviewees take on the burden of testimony in a way the viewer cannot – and if there is triumph in Once Upon a Time, it perhaps lies here. After catastrophe like that, the past cannot be made whole from the material of the present or vice versa; there is merely a gulf, an unbridgeable abyss between the two. And to live after the experience of war and with the memory of war is to make a home in this gap, in this discrepancy. To show us, those who have never seen it, what is found there, what sights are seen there, is rather extraordinary.