Since September 11, 2001, legal experts have focused significant attention on the lethal targeting of individuals by both the George W. Bush and Obama administrations. An equally significant legacy of the post-9/11 administrations, however, may be the decisions to target specific kinds of objects. Those decisions greatly affect the success of U.S. efforts to win ongoing conflicts, such as the conflict with the Islamic State of Iraq and the Levant (ISIL). These decisions may also become precedents for military attacks that states consider lawful, whether carried out by cyber or kinetic means, in future armed conflicts.To achieve the goal of destroying ISIL, President Obama embraced what many in the international law community long regarded as off-limits: targeting war-sustaining capabilities, such as the economic infrastructure used to generate revenue for an enemy's armed forces. Although the weight of scholarly opinion has for years maintained that such objects are not legitimate military targets, the existing literature on this topic is highly deficient. Academic discussion has yet to grapple with some of the strongest and clearest evidence in support of the U.S. view on the legality of such targeting decisions. Indeed, intellectual resources may be better spent not on the question of whether such objects are legitimate military targets under the law of armed conflict, but on second-order questions, such as how to apply proportionality analysis and how to identify limiting principles to guard against unintentional slippery slopes. In this article, I discuss the legal pedigree for war-sustaining targeting. I then turn to identify some of the most significant second-order questions and how we might begin to address them.
3 The Self-declared Islamic State (Da‘esh) and Ius ad Bellum under Islamic International Law