The United Nation’s Convention on Certain Conventional Weapons (CCW), also known as the Inhumane Weapons Convention, is about to take the first small step toward an international ban on killer robots. Activists have been agitating for years for a preliminary ban on fully autonomous lethal weapons, which the US Defense Department defines as weapons that \once activated, can select and engage targets without further intervention by a human operator.\ That includes, say, drones that drop bombs automatically when they reach their targets. But the technology for killer robots arguably already exists. The CCW has convened a four-day informal meeting of experts in Geneva to discuss how much autonomy is conscionable in robots that have the capacity to kill humans.