A new article from Nathan Wood titled 'Proportionality and combat trauma' from Nathan Wood was recently published in Philosophical Studies journal.

The principle of proportionality demands that a war (or action in war) achieve more goods than bads. In the philosophical literature there has been a wealth of work examining precisely which goods and bads may count toward this evaluation. However, in all of these discussions there is no mention of one of the most certain bads of war, namely the psychological harm(s) likely to be suffered by the combatants who ultimately must fight and kill for the purposes of winning in conflict. This paper argues that harms to one’s own soldiers must be included in proportionality judgments, and goes on to argue that one of the most significant harms one’s soldiers face are the psychological stresses and traumas associated with combat. The arguments draw on a growing wealth of psychological literature exploring the connections between combatancy and psychological trauma, and highlight, in particular, the uniquely negative impact which killing has on a combatant’s mental well-being. The paper concludes that these factors place an almost certain and rather weighty negative weight in any proportionality calculations concerning wars with ground combatants who must fight “up close and personal”, and that for more remote warfighters, there is also evidence to show that they may suffer deep psychological harm as a result of their combat roles as well. The argument, however, does not attempt to demonstrate that these factors render war impermissible. Rather, it merely shows that these harms, or bads, which can be quite significant, must be factored into our considerations of proportionality. The arguments themselves are rather uncontroversial, but they bring to light an element in the moral calculus which is sadly overlooked in most discussions of the ethics of war.