Quite apart from ethics and law, I find it impossible to see what contribution these weapons make to winning wars. The killing of officers merely sees others replace them, eager for revenge. The original Predator was intended for surveillance but was adapted for bombing specifically to kill Osama bin Laden. When he was finally found, the drone was considered too inaccurate a device to risk, and old-fashioned boots-with-guns had to be sent instead.
As for the inevitable killing of civilians, however few or many, this is not just "collateral damage" but critical to victory or defeat. It does not occupy or hold territory and it devastates hearts and minds. Aerial bombardment has long been a questionable weapon of war. It induces not defeat but retaliation.
Yet each week Obama apparently sits down and goes through a "kill list" of Muslims he intends to eliminate, with no judicial process and no more identification than the word of a dodgy spy on the ground. At least Britain's drones in Helmand, we are told, are used only in close air support for ground troops.
Since the drone war began in earnest in 2008, there has been no decline in Taliban or al-Qaida performance attributable to it. Any let-up in recruitment is merely awaiting Nato's departure. The Afghan president, Hamid Karzai, has called the attacks "in no way justifiable". The Pakistan government, at whose territory they are increasingly directed, has withdrawn all permission.