It is a fantasy that just will not die. Another Kremlin security scare, another flash of speculation online, another round of breathless commentary. Maybe someone is finally trying to kill Vladimir Putin. Maybe that is what it will take to end the war. One clean shot. One collapsing regime. Peace at last. But if that idea is serious – if we are not just indulging a lurid Western daydream – then we need to ask a much harder question.