Thomas Aquinas Between Just War and Pacifism

Some recent authors have argued that Aquinas deliberately integrated a pacifist outlook into his just war theory. Others, by contrast, have maintained that his rejection of pacifism was unequivocal. The present article attempts to set the historical record straight by an examination of Aquinas's writings on this topic. In addition to Q. 40, A. 1 of Summa theologiae II–II, the text usually cited in this connection, this article considers the biblical commentaries where Aquinas explains how the Gospel "precepts of patience," especially Matthew 5:39, "Do not resist evil," should be interpreted in light of the doctrine of just war. The article concludes that Aquinas formulated a two-stage theory whereby pacifism was rejected as a suitable form of agency for the state (respublica), while it was affirmed as the appropriate response to evil for the agency of the church (ecclesia).