Research on rebel movements associates group fragmentation with infighting, spoiling, and defection as victory against a common enemy nears. In contrast, we show that pro-government militias (PGMs) face unique incentives which lead them to emulate government behavior. When confronting a common enemy, PGMs highlight their value by signaling their comparative advantage vis-a-vis the central government. As victory nears, however, PGMs act to ensure their survival beyond the conflict by emulating the rhetoric and behavior of state security forces. We illustrate these patterns through a case study of the Iraqi coalition against the Islamic State (IS). We collect a large corpus of social media messages from accounts associated with the Iraqi government, the Kurdish Regional Government, and the Popular Mobilization Forces (PMF), a collection of pro-government militias mobilized to defeat IS. We find that the content of PMF messages shifts as conflict progresses. At the height of the IS threat, PMF messages played to the group's base and emphasized its distinctiveness from government forces. As victory over IS became more likely, PMF messages converged with government messages, increasingly emphasizing professionalism and eschewing sectarianism. This behavior sheds light on the changing incentives and constraints confronting PGMs as conflict processes evolve.