WARNING! It is to be noted that some of the sources used in this series, as well as direct quotations, display or describe in graphic detail acts of terror, rape, murder, torture, and other crimes against humanity. Extreme discretion and sensitivity are to be advised when reading such supporting material. The sources have been chosen to highlight and document the severity of these crimes and should be treated as such, as well as with the utmost sensitivity and dignity to the victims of such inhuman brutality.

An Overview

‘Those who wage war justly aim at peace, and so they are not opposed to peace, except the evil peace, which Our Lord “came not to send upon earth”’ [1]

The contemporary world is torn with conflict, and as such, in fidelity to Our Lord, Holy Mother Church must respond to such tragedy with a call for peace, while providing humanitarian and diplomatic aid where appropriate. This response must be firmly grounded in Catholic tradition and charity, reflecting the understanding of the tradition of just war, and must not ‘condemn every possible form of social conflict,’ especially when a conflict has arisen out of ‘militarism and exaggerated nationalism, and from related forms of totalitarianism.’ [2] Not all war is sinful; only unjust war, as ““[t]rue religion looks upon as peaceful those wars that are waged not for motives of aggrandizement, or cruelty, but with the object of securing peace, of punishing evil-doers, and of uplifting the good.”’ [3] A response to the conflicts that plague our lands cannot therefore be one of indifference to evil.

This series intends to apply the Catholic tradition of just war to a number of contemporary conflicts, in order to better inform the laity and recommend a reform in the current position of Catholic aid agencies’ responses to such humanitarian crises as well as to the papacy of Leo XIV. The present article establishes the theological and doctrinal foundation upon which each subsequent part of the series will rest. Readers are encouraged to consult this article before engaging with the applied analyses in future parts.

Definitions

A brief definition of what is meant by the term ‘just war’ is warranted before providing a detailed analysis of the term in relation to Catholic tradition, as well as a definition of what ‘tradition’ is, as both are key to understanding that the Church has not changed, nor can she, her teaching on such matters, and that those who suggest otherwise are delving into error. Just war, defined in the Catechism of the Catholic Church as requiring the four following criteria, is ‘military force [that] is morally justified’ and therefore not a sin: namely, ‘the suffering inflicted by the aggressor must be lasting, grave and certain; all other peaceful means must have been shown to be ineffective; there are well-founded prospects of success; [and that] the use of arms […] must not produce evils greater than the evil to be eliminated.’ [4] Catholic tradition is made up from Sacred Scripture, the writings and works of the Church Fathers when they are in agreement, plus later theologians such as Thomas Aquinas, as well as the Magisterial teaching of the Church. [5] Particularly relevant for the tradition of just war are the works of Augustine and Aquinas; the books of Deuteronomy and Numbers in the Old Testament, as well as Luke in the New Testament; and Conciliar legislation such as Gaudium et Spes and other encyclicals such as Pacem in Terris and Fratelli Tutti. Combined, these set forth conditions and theological backing for why, in some circumstances, war is necessary and morally justified.

The writings of the Aquinas further these prerequisites with three additional principles. Firstly, that ‘the authority of the sovereign by whose command the war is to be waged’ must be authoritative. Secondly, that ‘a just cause is required, namely that those who are attacked, should be attacked because they deserve it on account of some fault.’ And finally, ‘that the belligerents should have a rightful intention, so that they intend the advancement of good, or the avoidance of evil.’ [6] These prerequisites, which form Catholic tradition on the matter of just war, will be used as the basis for the analysis of each conflict treated in this series. It is important also to note that ‘a war of aggression is intrinsically immoral’ and, therefore, one can never legitimately claim the doctrine of just war in such circumstances. [7]

Holy Scripture

First, one should turn to what Sacred Scripture says about the concept of a just war. While many well-meaning people often use Sacred Scripture as ‘evidence’ for the pacifism of Christianity, such a simplistic and one-dimensional view is against the teaching of the Church. [8] Consequently, when it is repeated, it leads to further scandal and error for both the laity and the preacher. ‘If thou go out to war against thy enemies, and see […] the numbers of the enemy’s army greater than thine, thou shalt not fear them: because the Lord thy God is with thee.’ [9] Far from condemning war, God calls us to trust in Him, that He ‘is in the midst of you, and will fight for you against your enemies’ when the war is just and conformed to His will, the will of the Just Judge. [10] Furthermore, in doing ‘all things which the Lord had commanded Moses’ to do, God calls ‘all that are able to go forth to war’ to mobilize. [11] Therefore, as the law of the Old Covenant, of which we as Christians are inheritors, as Our Lord did ‘not come to destroy, but to fulfill,’ does not outright condemn war, and calls us to it in certain circumstances, just war theory has an Old Testament scriptural basis. [12]

What then does Our Lord say when He was ‘made flesh, and dwelt amongst us?’  [13] How can one go to war when one must ‘[l]ove your enemies: [and] do good to them that hate you?’ [14] War, when fought for justice, and the hatred therefore involved when fighting an enemy, is not necessarily a sin if it is directed toward correction of the sin of the other, rather than his nature, as Aquinas says. [15] Due to the nature of man, one must hate what is contrary to oneself, so if we are in friendship with God then we must hate evil. [16] However, this should be done corporately, and with no malice toward the individual person; as they may be ‘contrary to us,’ and therefore our enemies, ‘[t]hey are not, however, contrary to us, as men and capable of happiness: and it is as such that we are bound to love them.’ [17] As Our Lord says ‘[b]ut as for those my enemies, who would not have me reign over them, bring them hither, and kill them before me.’ [18] Therefore, it would seem that God allows for war if it is not done out of malice; and that certain types of war, such as defense against evil, are not done so out of hatred that is itself evil, rather out of love, and therefore do not violate charity. As Augustine states, ‘[t]he real evils in war are love of violence, revengeful cruelty, fierce and implacable enmity, wild resistance, and the lust of power,’ as such a defensive war, conformed to the will of God, against evil itself, is not a ‘real evil,’ merely a necessary act. [19]

The Church Theologians

Secondly, one should look at what the Church Fathers have to say on just war. The two of importance here are Augustine and Aquinas. The works of Aquinas will be quoted throughout this series, and therefore to avoid repetition, Augustine alone will be treated in this section, as he provides a primary source of inspiration for Aquinas. Augustine, in his correction of the heretics, the Manichees, in his Contra Faustum, argues that there is clearly a continuity between the Old Testament and the New, especially on the topic of war and its divine allowance. [20] He also emphasises that the ‘motivations and justifications’ for a war are important in this regard. [21] Augustine’s understanding of when a war is to be called just or not is therefore based upon the continuity of the Old Testament and shows that ‘when [a] war is undertaken in obedience to God, who would rebuke, or humble, or crush the pride of man, it must be allowed to be a righteous war.’ [22] Wherefore the violence against evil ‘is not a bodily action, but an inward disposition,’ and therefore a fulfillment of the commands of the New Testament to ‘[l]ove your enemies,’ ‘for we must serve God not for temporal happiness in this life, but for eternal felicity’ in the next. [23] This cannot happen if we, in our idleness, let evil go unchallenged, especially in cases that warrant the harsh correction that can only come through the violence of war, as ‘we often have to act with a sort of kindly harshness, when we are trying to make unwilling souls yield, because we have to consider their welfare rather than their inclination.’ [24] Peace and justice can therefore at times only be obtained by waging war, even if that noblest of aspirations, peace, should be our goal, as Augustine states: ‘but war is waged in order that peace may be obtained.’ [25] Therefore, according to Augustine, war at times can be a necessity, and therefore can be just.

Ecumenical Councils and Recent Magisterial Teaching

Finally, one should look at what the Magisterium of the Church has had to say on the matter of just war. Rather than survey the entire history of the Church, and as the twentieth century was witness to the horrors of two world wars, let us look at what the Second Vatican Council and recent teaching have to articulate. Gaudium et Spes reaffirms Sacred Scripture when it ‘declares that the artisans of peace are blessed.’ [26] And as shown, a military force kept for defensive purposes is a legitimate way of keeping peace, and therefore its members are also ‘artisans of peace.’ ‘Those too who devote themselves to the military service of their country should regard themselves as the agents of security and freedom of peoples.’ [27] Gaudium et Spes does not deviate from Sacred Scripture and the Church Fathers; it reiterates that peace should always be our goal, but that there are circumstances when war becomes unavoidable. For ‘we should not let false hope deceive us. For unless enmities and hatred are put away,’ we are doomed to continue the tragedy of war until our destruction. [28]

Perpetual peace can only be achieved with complete disarmament of the world, it seems, an idea found in the earlier encyclical Pacem in Terris, which states that ‘justice, right reason, and the recognition of man’s dignity cry out insistently for a cessation to the arms race.’ [29] However, we do not yet live in such a world, and therefore logically we must be prepared to wage a war in defense to preserve justice and peace, until such a day dawns. Fratelli Tutti follows in this same tradition, lamenting the tragedy of war and conflict and calling for peace and disarmament in the world, whilst still acknowledging that the peace and harmony that will come from unity cannot happen until ‘the end of time, when peace will gloriously achieve completion […] [and all] will be gathered together with the Father.’ [30] As ‘loving an oppressor does not mean allowing him to keep oppressing,’ the tradition of the Church is clear: peace is the supreme goal, but justice is its necessary precondition. [31]

Conclusion

The foregoing survey of Sacred Scripture, the Church Fathers, and the Magisterium establishes a coherent and consistent Catholic tradition on just war. This tradition neither glorifies war nor naively dismisses it; it applies reason and charity to the gravest of human actions. The four criteria of the Catechism – grave and certain suffering, exhaustion of peaceful means, well-founded prospects of success, and proportionality of means – together with the Thomistic prerequisites of legitimate authority, just cause, and right intention, will serve as the evaluative framework for the conflicts examined in the following parts of this series. Readers are encouraged to return to this article as a reference point throughout.