Andrew Miller’s fourth book has many parallels with Pat Barker’s Double Vision, focusing on war through a photographer’s lens and raising issues about journalistic complicity. Like Barker, Miller is a highly regarded historical novelist, struggling here in exactly the same way to convey recent political events through a psychological form.

After reporting on the genocide in N—, a central African country, the photojournalist Clem Glass cracks up on his return to the UK. He hops between locations looking for some holding ground: London, Somerset, Scotland (where his father is living in a religious retreat), Brussels and Canada. There he jets in to visit his journalist friend, Silverman, who was present at the same massacre. “We made ourselves sick, Clem” — is how they analyse the event.

By now we understand the design of Miller’s story, intending us to experience the event through its mediators — the journalists who were there at N—. But since their photographs and copy reside outside the novel, we are left with self-absorbed shells. Glass’s damaged character verges on the romantic; a world-weary existentialist smoking listlessly in his bedroom and thinking aloud like a solo actor in a film: “Did he fear the wearing thin of his faith in human iniquity? . . . Do you really know what we saw? The question then had seemed outrageous and easily answered. He had the evidence in Ektachrome and on rolls of Tri X 400.”

Events so profoundly horrific as the massacres in Rwanda (Miller’s disclaimer that the massacre at N— is based on the well-documented atrocity in Rwanda in 1994, but is not about the Rwandan genocide, is pretty transparent. At least once N— is referred to as R— in the uncorrected proof copy) set up expectations in the reader for revelation, for some delivery of the “evidence”. But we already know the evidence in this case; we’ve had our own encounter with the massacre of Tutsis by Hutus from reading journalists’ accounts. So when Glass makes ruefully inadequate statements about the genocide — such as: “she returned the camera’s stare with a gaze of the quietest imaginable outrage” — we can’t help but compare notes with what we already know.

The novelist has to mediate a political event more skilfully than a journalist and the tension between subject and mediator is what should be driving the story. In The Optimists there is more awkwardness than tension.

Yet forcing the political story through a psychological aperture does produce some disquieting moments, from Glass’s depressed sister’s fear of the dark and his own fear that his eyesight may have been damaged by the horror of what he’s witnessed. Several characters seem products of a frenzied state of mind, such as Ruzindana, the butcher of N— (President Habyarimana of Rwanda? How could you ever make him up?), whom Glass encounters in Brussels. While Simon Truelove (founder of a religious community), Pauline Diamond (the good carer in the psychiatric hospital), Dr Boswell (a composite of Dr Johnson and Boswell?) are evocative in different ways. And Clem Glass . . . is this a nod to the war correspondent and Beirut hostage, Charles Glass?

Silverman, organising food drops to the homeless in Canada, inspires Glass to replicate something similar. His wanderings end for a while when he takes his sister out of a psychiatric hospital to Somerset, and becomes her principal carer in their aunt’s cottage. Glass’s self-conscious move to “do good” after seeing so much evil is the most effective and at times moving part of what is essentially a story about unhappy families looking after one another. Hinging a massacre on to the story attempts to give it unearned gravitas.

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