<p>The key representatives of the bellicist approach in historical sociology argue that the wars between states have been the central catalyst of state formation. Furthermore, they insist that, unlike inter-state wars, civil wars generally do not engender state formation. Civil wars are usually understood to be highly destructive to the process of state-building. In this article, I question the view that civil wars are always harmful to the development of state apparatuses. Instead, I argue that civil wars, just as inter-state wars, can make or break states. I identify four main factors that can make civil wars into successful state builders: a conclusive and total war victory, the political neutralisation of the hostile opposition, the successful curbing of ethnic factionalism, and the presence of continuous economic growth. I illustrate my argument with the numerous historical examples of civil wars throughout the world.</p>