Just War Theory - Then and Now

A series of debates in the Middle Ages gave rise to what we call “Just War Theory”: an attempt answer the question about when, if ever, a nation is morally justified in engaging in warfare. The debate was between the pacific half of Christianity, which claimed that violence was never permissible, even in defense of self or others, and the moderate half of Christianity, which argued that combat would be morally permissible if it were purely defensive. The debates were not abstract: the pressing politics of the day were shaped by the Islamic invasion of Spain in 711 A.D., of France in 732 A.D., and of southern Italy in the early 800’s. (The Crusades, originally envisioned as a defensive counter-attack against the home base of these Muslim armies, would being around 1095 A.D.)

The debates went into great detail about what might or might not be considered ethical conduct in warlike situations. Jonathan Barnes, at Oxford University, writes that

the question of what part the clergy might play in warfare looms large in medieval discussions; but its interest is purely antiquarian and theological.

The details of what a priest in Europe in the middle ages might be allowed to do in the military could easily appear as an irrelevant discussion to the modern reader, at until Alfred Freddoso writes that

the medievals generally argued that clerics are forbidden to bear arms or to kill even in a just war. Given the powerful pacifist tendencies in current Christian thought, it would hardly be shocking if someone were to ask why these medieval arguments might not apply to all Christians, nonclerics as wells as clerics, with the result that Christian pacifism could be viewed as a natural development of just-war theory. The topic is thus far from antiquarian.

It seems that medieval debates about pacifism and just war theory will always be relevant to this world; wars will always bring cause philosophers to pose these questions.