Just war
A long tradition of working out the conditions under which killing in war can be morally permissible. It is usually split into the grounds for going to war at all and the rules for how fighting may be conducted once it has begun, with a later part on how a war should be ended. Its purpose is to mark a line between war that can be justified and war that cannot.
The Christian doctrinal tradition — running from Augustine's City of God (early fifth century) through the high medieval scholastics (Aquinas, Vitoria, Suárez) to the modern international-legal version (Grotius onwards) — that articulates the conditions under which Christians may permissibly engage in killing in war. The traditional structure has two parts: jus ad bellum (the conditions for going to war justly) and jus in bello (the conditions for fighting justly once at war), with a later addition of jus post bellum (the conditions for concluding war justly).
Etymology§
Bellum justum in classical Latin; the technical Christian doctrinal use is medieval-scholastic. Augustine's quaestiones in Heptateuchum and City of God are the patristic foundations; Aquinas's Summa Theologiae II-II q.40 is the high medieval consolidation; Francisco de Vitoria's De jure belli (1539) and Hugo Grotius's De jure belli ac pacis (1625) are the early-modern bridges into modern international legal theory.
For the moral-injury corpus, just-war theory is the doctrinal framework that contemporary critics — most explicitly Robert Emmet Meagher in Killing from the Inside Out — read as having functioned not to constrain Christian killing but to authorise it under specified conditions. The argument turns on the empirical fact of moral injury: if the contemporary clinical literature is right that combatants suffer lasting moral wounds from acts they performed under just-war authorisation, then the tradition's claim to be morally protective of combatants is empirically refuted. The wound happens whether or not the war was just by the tradition's own criteria.
The position is contested inside Christian ethics. Defenders of the just-war tradition (Nigel Biggar, Daniel M. Bell, James Turner Johnson) argue that the existence of moral injury does not show the tradition is vacuous — it shows that even just killing causes moral damage, and the tradition was never claiming otherwise. Pacifist critics (Hauerwas, John Howard Yoder, Meagher) read the same evidence as showing the tradition has functioned as moral cover and that the appropriate Christian response is the rejection of permissible Christian killing, not its constrained authorisation. The disagreement is not new — it runs through the entire history of Christian engagement with state violence — and the contemporary moral-injury literature has given it new empirical material to work with rather than resolving it.
For the corpus, just-war is the doctrinal background against which most of the theological moral-injury literature is positioning itself, with the position varying by author. The construct appears in Meagher as the polemical target, in Kinghorn as part of the inherited theological framework being reworked, and in Soul Repair as a context the book engages without making a single definite position the central argument.