In a recent book, Adil Ahmad Haque attempts to reconcile between jus in bello and 'deep morality', by constructing international humanitarian law (IHL) as a prohibitive system, the constitutive aim of which is non-consequentialist: to 'serve' combatants by providing them with rules that if followed would allow them to better conform to their moral obligations. After situating Haque's approach within the current debate between traditional and revisionist just war theorists, this review essay asks whether constructing IHL as a prohibitive set of norms is indeed sufficient to reconcile it with morality. By utilizing insights from legal realism, I argue that when determining whether law prohibits or permits, it is not sufficient to analyse pure legal concepts but, rather, we have to ask how law functions. This analysis reveals that IHL can be facilitative of action - meaning, of war - even if it is construed as formally prohibitive. This, in turn, calls for two conclusions: on the ethical level, when considering the morality of IHL, its facilitative function should be taken into account. On the legal level, recognizing the facilitative nature of IHL might assist us in answering key unresolved questions - namely, whether the material, spatial, and temporal thresholds for the application of IHL should be high or low.