This article discusses the future potential of a norm that emerged recently from the academic literature surrounding the ethics of war, and that echoes a number of political and moral viewpoints around the necessity of terminating ongoing and bloody wars that otherwise are unnecessarily prolonged: the norm of 'jus ex bello'. While it argues in favor of a possibilistic approach to normsin order to argue why norms should develop, it is necessary to analyze whether they could developthis article finds that jus ex bello might be an appropriate response to some of the arguments in favor of the need for normative change in warfare. However, four major obstacles to this potential innovation are identified, grounded in cultural history, politics, morality and cognition. Based on the further examination of these, the article goes on to make suggestions for institutional design initiatives, in themselves dependent on possible significant social and cultural evolution, that would favor normative change and the development of jus ex bello.
Policy Implications• It is important to find institutional responses to the unnecessary prolongation of conflicts. Jus ex bello, a new norm complementary to the existing set of rules on the ethics of war, could meet these expectations and provide guidelines to assist the decision to end a war. This vision is based on a future-oriented approach to the ethics of war and international justice.