Lethal military robots: who is responsible when things go wrong?

Although most unmanned systems that militaries use today are still unarmed and predominantly used for surveillance, it is especially the proliferation of armed military robots that raises some serious ethical questions. One of the most pressing concerns the moral responsibility in case a military robot uses violence in a way that would normally qualify as a war crime. In this chapter, the authors critically assess the chain of responsibility with respect to the deployment of both semi-autonomous and (learning) autonomous lethal military robots. They start by looking at military commanders because they are the ones with whom responsibility normally lies. The authors argue that this is typically still the case when lethal robots kill wrongly - even if these robots act autonomously. Nonetheless, they next look into the possible moral responsibility of the actors at the beginning and the end of the causal chain: those who design and manufacture armed military robots, and those who, far from the battlefield, remotely control them.