Humanitarian diplomacy typically relies on principled engagement to promote compliance with International Humanitarian Law. Yet, many non-state armed groups operate outside formal legal frameworks and lack incentives to align with them. This post argues for a more pragmatic approach: engaging armed groups through the drivers that already resonate with their operational logic. Drawing on concrete examples, it explores five strategic rationales for restraint—such as legitimacy, efficiency, and internal control—and discusses how these can be leveraged to reduce violence and limit human suffering in armed conflict.