Although militias have received increasing scholarly attention, the concept itself remains contested by those who study it. Why? And how does this impact contemporary scholarship on political violence? To answer these questions, we can focus on the field of militia studies in post–Cold War sub-Saharan Africa, an area where militia studies have flourished in the past several decades. Virtually all scholars of militias in post–Cold War Africa describe militias as fluid and changing such that they defy easy definition. As a result, scholars offer complex descriptors that incorporate both descriptive and analytic elements, thereby offering nuanced explanations for the role of militias in violent conflict. Yet the ongoing tension between accurate description and analytic definition has also produced a body of literature that is diffuse and internally inconsistent, in which scholars employ conflicting definitions of militias, different data sources, and often incompatible methods of analysis. As a result, militia studies yield few externally valid comparative insights and have limited analytic power. The cumulative effect is a schizophrenic field in which one scholar’s militia is another’s rebel group, local police force, or common criminal. The resulting incoherence fragments scholarship on political violence and can have real-world policy implications. This is particularly true in high-stakes environments of armed conflict, where being labeled a “militia” can lead to financial support and backing in some circumstances or make one a target to be eliminated in others. To understand how militia studies has been sustained as a fragmented field, this article offers a new typology of definitional approaches. The typology shows that scholars use two main tools: offering a substantive claim as to what militias are or a negative claim based on what militias are not and piggy-backing on other concepts to either claim that militias are derivative of or distinct from them. These approaches illustrate how scholars combine descriptive and analytic approaches to produce definitions that sustain the field as fragmented and internally contradictory. Yet despite the contradictions that characterize the field, scholarship reveals a common commitment to using militias to understand the organization of (legitimate) violence. This article sketches a possible approach to organize the field of militia studies around the institutionalization of violence, such that militias would be understood as a product of the arrangement of violence. Such an approach would both allow studies of militias to place their ambiguity and fluidity at the center of analyses while offering a pathway forward for comparative studies.