This chapter covers targeting law, which governs the ways in which weapons may be used in armed conflict. As integration of autonomous control into weapon systems necessarily affects the procedures to be followed in operating those weapons, it must be assessed with respect to the rules of targeting law. Specifically, autonomy in weapons relates to the ‘procedural’ side of targeting: questions of how the legal status of a potential target is to be assessed, what precautions must be taken in planning and conducting an attack, who is responsible for those tasks, and so forth. Accordingly, the first part of the chapter discusses the necessity for and general form of human involvement in planning and conducting autonomous attacks. It refutes the view that human involvement would or could be entirely missing from operations involving autonomous weapons. The second part steps through a model 6-step targeting process to explain the respective contributions of humans and autonomous systems at each stage.

This chapter links the distinguishing technological features of autonomous machines, identified in the previous chapter, to matters which are the subject of legal regulation: the decisions and actions of combatants, and the behaviour of weapon systems. It outlines the effects that weapon autonomy I likely to have on military decision-making processes and discusses the novel sources of risk and modes of failure associated with operating complex autonomous machines in combat. The problem of how to categorise autonomous weapons for legal purposes is addressed, as a response to suggestions by some commentators that weapon systems which are able to ‘step into the shoes’ of soldiers in some respects should perhaps be considered to be something more than just weapons when assessing their legal compliance. Finally, the conditions under which use of autonomous weapons may transgress the law are identified, as preparation for the detailed legal analysis to follow in the remainder of the book.