America’s so called “war on terror” did not end when George W Bush left office. Under Barack Obama, the covert war entered a new phase, one of increasing reliance on missile strikes from aerial drones, with these assassinations approved by the US president himself.

Drone strikes tend to happen where journalists cannot safely verify the damage they inflict; mountainous tribal corners of Pakistan; the Yemeni desert; lawless Somalia. Last year I sat next to a pilot in the cockpit of a passenger plane flying across northern Somalia. The Somali pilot told me the skies around him were constantly busy with American military activity, including unmanned drones.

One recent death ascribed to a drone attack was that of Saad al-Shehri, a senior al-Qaeda figure in Yemen, a country which is home to probably the most active branch of the al-Qaeda franchise anywhere.

Mr al-Shehri had fought in Afghanistan, where he was captured by the Americans. He was released from six years in Guantanamo Bay to custody in Saudi Arabia. The Saudis tried to “rehabilitate” him and persuade him to give up his jihadist ways. It didn’t work and he ended up across the border in Yemen.

The Americans haven’t confirmed Mr al-Shehri’s death from a Hellfire missile, but they haven’t denied it either. And from Washington’s point of view, the al-Qaeda figure was so far beyond the norms of justice in the wilds of southern Yemen that a drone strike was the most convenient method of dealing with him once and for all.

Yet for every story like this one, in this case leaked by Yemeni officials, there are many other stories which go untold; the deaths of innocent bystanders including children, the “collateral damage” which occurs because drone strikes are not as clinical a method of warfare as its advocates would have us believe.

More from Channel 4 News: ‘Terror and stress’ in the shadow of the drones

President Obama himself has set out his criteria for the deployment of drones. He has said the target must be authorised under US law, that the threat must be serious rather than speculative, that the target must be beyond capture, that care must be taken to avoid civilian casualties and that American citizens plotting terror should still be afforded their constitutional rights.

This report by Stanford and New York Universities makes a mockery of the president’s criteria as they apply to drone strikes in Waziristan, along the Pakistan-Afghanistan border. The president is a Harvard-educated lawyer, and would no doubt prefer his assassination policy operated within legal norms. Yet there is surely very little that can be described as normal about drone warfare.

Does any of this matter with a presidential election approaching? Only in that it helps Mr Obama win a second term. He has pledged to bring American troops home from Afghanistan, as he has from Iraq. He is increasingly reliant on US Special Forces and drone technology to fight America’s wars for him.

And this means far fewer body bags being flown home containing the remains of American servicemen and women. Couple this with the killing of Osama bin Laden by US Navy Seals, and Obama seems to be giving America what it wants: if not war without cost, then war without visible consequences.

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