the U.S. seems to be struggling to adapt its 20th century moral code of warfare to the 21st century practice of sending flying robots into other countries to kill people. It appears that drones are evolving faster than Americans’ ability to understand how, legally and ethically, to use them. […] In a way, drones represent the much delayed coming of age of a field that has experienced a prolonged adolescence, namely robotics. For decades robots stumbled along on the ground, slowly and clumsily, rarely achieving even bipedal locomotion. Right now the apex of consumer robotics is that humble domestic trilobite, the Roomba. But it turns out that the earth’s surface is simply not the robot’s natural domain. When robots take to the air, they’re faster and nimbler and more graceful than humans will ever be. All along, robots just wanted to be drones. […] Drones bring that asymmetrical dynamic out into the real world: a drone is the physical avatar of the virtual presence of a real person. They provoke a new kind of anxiety, quite unlike the nuclear terror of the 1980s or the conspiracy-theory paranoia of the 1990s. They’re a swarming, persistent presence, low-level but ubiquitous and above all anonymous. They could be al-Qaeda or your government or your friends and neighbors.