Going Medieval: Targeted Killing, Self-Defense, and the Jus ad Bellum Regime

The U.S. targeted killing policy employs drone-launched missiles to kill suspected terrorists and insurgents in countries in which the U.S. is not clearly involved in an armed conflict. It has justified the program on two bases: that the U.S. is in an armed conflict with Al Qaeda and associated organizations; and that the U.S. can engage in the strikes as an exercise of self-defence. These strikes constitute a use of force against the states in which the targets are located, in jus ad bellum terms, and the claim to the right of self-defence is similarly reliance upon a jus ad bellum justification. This chapter examines the validity of this self-defence claim, and assesses the potential impact that the policy might have on the future development of the jus ad bellum regime. Some of the implications and rationales for the policy reflect a return to older ideas about war, some dating to the medieval period, which were deliberately rejected in the design of the modern jus ad bellum regime in the U.N. system.The broad claim of self-defence cannot be sustained without identifying the specific armed attacks to which the use of force is responding, explaining exactly how the non-state actors (NSAs) targeted are connected to such attacks, and establishing how the states against which the use of force is ultimately employed are sufficiently responsible for those actions of the NSA. Blanket assertions of self-defence with reference to 9/11 cannot justify strikes against groups and states that had no involvement in 9/11. The core argument, that self-defence claims can justify the use of force against NSAs as such, regardless of the degree to which the states in which they are located are implicated in the NSAs’ operations, is inconsistent with current treaty law, customary international law, judicial decisions, and predominant scholarly opinion. Moreover, there are good reasons for rejecting arguments in favor of expanding the doctrine of self-defence to include preventative strikes, and collapsing the gap between the thresholds for justifying the use of force against states on the one hand, and establishing state responsibility on the other. A continuation of the targeted killing policy, together with acceptance of the rationales advanced in its defence, could significantly weaken the jus ad bellum constraints on the use of force against states. The expansion of the self-defence doctrine and weakening of its core principles would not be limited to targeted killing, but would apply generally to the use of force against states. Moreover, the policy implies a significant alteration to the relationship between the jus ad bellum and jus in bello regimes. The idea that one state could use force against another on the sole ground that it is engaged in an armed conflict with an NSA, would circumvent the jus ad bellum prohibition on the use of force altogether. All of this runs the risk of undermining the coherence of the overall system of laws that govern the use of force and armed conflict. While trying to adapt to meet the threat of terrorism, we run the risk of rejecting crucial parts of a system designed to reduce the incidence of armed conflict among states – ultimately a far more serious threat than transnational terrorism.