Marine A is guilty of an appalling murder. But Friday’s sentencing should reflect the wider context of the crime

The circumstances in which this crime took place cannot be ignored

It is impossible not to be sickened by the actions of Marine A. In September 2011, in a field in the Helmand province of Afghanistan, this until-then-exemplary sergeant performed a “battlefield execution” on a helpless Taliban fighter who was already badly wounded from an attack by a helicopter gunship.

Footage from a helmet camera worn by one of the Royal Marine’s two comrades (against armed forces rules) recorded the sergeant deliberately discharging a bullet into the Afghan’s chest. “Obviously this doesn’t go anywhere, fellas,” the Marine could be heard remarking. “I’ve just broken the Geneva Convention.”

His two colleagues were acquitted, but last month Marine A was convicted of murder, the first such verdict handed down to a serving soldier since the Second World War. In the intervening weeks, there has been much controversy over whether the identities of the defendants should be revealed, but the focus now is on Friday’s sentencing. At the law’s most punitive, Marine A faces mandatory life imprisonment.

There is a compelling case for severity. After all, it is our moral values – including the creation of, and adherence to, halfway humane rules of engagement – that are the only justification for our judgment of the Taliban, let alone our enforcing it at the point of a sword. The suggestion that we do not practise what we preach, that the Geneva Convention is only binding in the corridors of The Hague, and that violations by our own meet with nothing more onerous than a complacent shrug, exposes us to charges of hypocrisy, at best. As no less a figure than General Sir Nick Houghton, the Chief of the Defence Staff, has put it: “Murder is murder”; pleading for clemency “erodes the moral ascendancy over our enemies”.

Yet clemency is still what The Independent would have. Marine A fought for his country for nearly a decade. Whether or not it was right for Britain to go to war in Iraq and Afghanistan, the soldiers who risked – and forfeited – their lives deserve the same limitless respect and gratitude from those of us who did not.

The realities of such a life must also be considered. Not for nothing did General Sherman remark that “war is hell”. Marine A and his comrades lived and worked in conditions of discomfort, threat and fear nigh unimaginable to those who have not experienced them. We ask these people to face risks that would terrify us and commit acts that would appal us, with only camaraderie and a sense of duty to support them. The horrific violence that they witness, not least the deliberate killing and maiming of their comrades, cannot but leave a mark. Professional as they most certainly are, no amount of training can stop them being human beings; indeed, we would not want it to.

This is no defence of Marine A. Battlefield or no battlefield, this was murder. And yet the context in which the events took place are sufficiently extraordinary that they cannot be ignored. The place to reflect that is not in the verdict but in the sentence. Marine A must, of course, go to prison. But not for life. While soldiers cannot be outside justice, the intolerable pressures we ask them to bear do not count for nothing either.