Who may be killed in accordance with moral justice

When it is just to kill – for this must be our starting point – in a lawful war in accordance with moral justice (iustitia interna) and when it is not just to do so, may be understood from the explanations which were given by us in the first chapter of this book. Now a person is killed either intentionally or unintentionally. No one can justly be killed intentionally, except as a just penalty or in case we are able in no other way to protect our life and property; although the killing of a man on account of transitory things, even if it is not at variance with justice in a strict sense, nevertheless is not in harmony with the law of love. However that punishment may be just, it is necessary that he who is killed shall himself have done wrong, and in a matter punishable with the penalty of death on the decision of a fair judge. But we shall here say less on this point, because we think that what needs to be known has been sufficiently set forth in the chapter on punishments.

On killing for a fault that is intermediate between ill-fortune and deceit

But it must be observed that, between absolute wrong and unmitigated ill-fortune, a mean may often intervene which is composed, as it were, of both elements. In such a case, the action cannot be called purely that of a man having knowledge and intent, nor purely that of a man not having knowledge or acting against his will. To this class of actions,…[the Latin label] culpa [may be applied].