This chapter introduces the theoretical framework of state-building as lawfare. The chapter starts by outlining the building blocks of peripheral state-building: legal pluralism, nested sovereignty, gender cleavage, and armed conflict. Legal pluralism is an issue of fragmented social control. State–society struggles for social control are complicated because both the state and society are internally divided. The concept of nested sovereignty captures how the state is divided in imperial and federal settings. The central societal cleavage of state-building lawfare is gender. Both political and societal cleavages that drive state-building lawfare in the periphery are actualized and intensified by armed conflict. Building on this foundation, the chapter then theorizes state-building lawfare from above. In particular, it outlines when and why central and peripheral authorities promote non-state legal systems, as well as how conflict changes the political rationale of promoting legal pluralism. After that, the chapter interrogates state-building lawfare from below – focusing on individual choices between state and non-state legal systems. It also speculates about how conflict transforms the driving forces behind these choices – in identities and social norms – as well as resources, interests, and hierarchies, with a special focus on gender relations.