Despite the common reference to international humanitarian law (IHL) in the discourse and practice of international politics, international relations (IR) scholarship has yet to consistently engage in an analysis of IHL that extends beyond the relatively narrow specifications of its regulative and strategic effects. In this theory note, we argue that this prevailing focus leaves the discipline with an impoverished understanding of IHL and its operation in international politics. We propose that the study of IHL should be expanded through a deeper engagement with the law's historical development, the politics informing its codification and interpretation, and its multiple potential effects beyond compliance. This accomplishes three things. First, it corrects for IR's predominantly ahistorical approach to evaluating both IHL and compliance, revealing the complicated, contested, and productive construction of some of IHL's core legal concepts and rules. Second, our approach illuminates how IR's privileging of civilian targeting requires analytical connection to other rules such as proportionality and military necessity, none of which can be individually assessed and each of which remain open to debate. Third, we provide new resources for analyzing and understanding IHL and its contribution to "world making and world ordering."