This article develops wartime repertoires as institutional blueprints as an analytical lens for understanding rebel governance and post-conflict state formation: the splm as a political organisation, 1983–2023. It argues that the governance routines created by insurgent movements during war become durable organisational repertoires that shape how pos t-conflict states tax, adjudicate, command, and distribute authority. Drawing on within-case process tracing drawing on splm archives, new sudan council of churches documentation, oral histories with nasir and torit faction commanders, and ethnographic fie ldwork in juba, malakal, and yei., the paper links the theoretical debates identified in rebel governance theory (mampilly; arjona; kasfir); historical institutionalism on path dependence; migdal's 'state-in-society' framework. argues that the governance r epertoires developed by armed movements during insurgency are constitutive of not merely antecedent to post-conflict state institutions. to a comparative and historically grounded reading of South Sudan and the related cases assembled in the research d esign. The article advances three core claims. First, the SPLM/As wartime practices of taxation, military command, local justice, and movement discipline supplied both personnel and institutional habits to the post-2005 state. Second, personalized command and factional brokerage, while effective for insurgent survival, translated into fragmented chains of accountability once embedded inside state ministries and security institutions. Third, rebel governance legacies can be adaptive when they routinize local service delivery and negotiation, but they become pathological when coercive extraction is normalised as the primary technique of rule. The contribution is twofold: it