Fighting Justly in the XXth century

This dissertation addresses the rarely examined issue of disqualification of weapons from the battlefields. Most literature in International Relations and War studies take for granted the fact that weapons disappear from the battlefield due to their lack of tactical/strategical utility or because of their relative cost/efficiency vis-à-vis available alternative. This study challenges the rational character of these answers, arguing that they do not fully capture what explains variations in states weapons utilization. It suggests that, contrary to what these common views assume, laws of war play a crucial role in states decisions to use or not a weapon. More specifically, the core principles of laws of war are deeply rooted in military culture and underpin common representations of war. Therefore, perceptions of what laws of war should ban or allow (conceptualized as the notion of “fighting justly”) constitute the normative framework which underpins tactical, strategic, cost effective decisions with regards to weapons utilization. As such, the laws of war range of effects are wider than what is suggested by the dichotomic notion of “compliance”. Moreover, because the key principles of laws of war are profoundly ambiguous, their effects have greatly varied depending on how they have been understood over time, actors and levels (national, international, transnational). Through a carefully crafted historical account combining tools borrowed to ethics, security studies, sociology, phenomenology and anthropology, this dissertation retraces the different conceptions of fighting justly that have prevailed over the twentieth century and demonstrates how they highlight the trajectory of three weapons: chemical weapons, incendiary weapons, unarmed aerial vehicles. It thus presents an innovative re-reading of the impact of laws of war in states weapons utilization, and a more nuanced understanding of why certain weapon disappear from the battlefield.