K Chunjuanlung Rongmei

An ethical framework for assessing the morality of warfare that strikes a balance between realism and pacifism is provided by Just War Theory or tradition, which has its roots in ancient civilizations, and was developed as a systematic and coherent doctrine of military ethics by medieval theologians such as St. Augustine and Thomas Aquinas. The idea of waging a war for a just cause was first articulated in non-Western ancient literature, such as Hindu and Chinese philosophical writings, despite the fact that Just War Theory is typically thought of as being exclusively Western. The Theory has provided foundational ethical and legal frameworks that have regulated warfare for millennia. However, it faces challenges from modern hybrid and asymmetric warfare, particularly cyberattacks and non-state actors, which complicate traditional war-peace distinctions. This study reviews Just War Theory's historical development and its relevance and applicability to grey-zone warfare, analysing how its principles, such as just cause and non-combatant immunity, apply to non-kinetic threats. Through conceptual analysis and case study, it also examines the challenges posed by non-state actors like terrorists, private military companies (PMC), militias, etc., which complicate self-defence under international law. The breakdown of non-combatant immunity in urban warfare leads to significant civilian casualties, disproving claims that the tradition is outdated or inapplicable. Just War Theory remains a critical moral guide, adaptable to contemporary conflicts, necessitating revisions to address new challenges and uphold ethical accountability amidst evolving warfare dynamics.