[A recent] successful exercise in autonomous robotics could presage the future of the American way of war: a day when drones hunt, identify and kill the enemy based on calculations made by software, not decisions made by humans. The demonstration laid the groundwork for scientific advances that would allow drones to search for a human target and then make an identification based on facial-recognition or other software. Once a match was made, a drone could launch a missile to kill the target. The prospect of machines able to perceive, reason and act in unscripted environments presents a challenge to the current understanding of international humanitarian law. The deployment of such systems would reflect a paradigm shift and a major qualitative change in the conduct of hostilities," Jakob Kellenberger, president of the International Committee of the Red Cross, said at a conference in Italy this month. Drones flying over Afghanistan, Pakistan and Yemen can already move automatically from point to point, and it is unclear what surveillance or other tasks, if any, they perform while in autonomous mode.