The future of "killer drones" is one in which, instead of being operated by remote control, the drones themselves make the decision to attack. If (and when) that happens, who will be held responsible–the machine or the military that launched it?
The First World War was launched with a single assassination. In the March 17th edition of the New York Times, Bill Keller quotes Stephen of Human Rights Watch as saying, "This is something people seem to feel at a very gut level is wrong. The ugh factor comes through really strong."