The Just War Theory

by Brother John Raymond


There is no doubt in the minds of many that the issue of war and the Christian conscience has been a long-standing problem. When asked about war some would allude to the Just War Theory. What is this theory and how did it come about? Is it still applicable with modern warfare? What are the arguments for and against a just war? These are the questions that we wish to investigate.

War Defined

Before talking about a just war, one must define what is meant by war. It is "defined as a state of conflict between two or more sovereign nations carried on by force of arms."(1) Looking into this definition more closely we see that war involves a state of conflict contrasted with passing conflicts such as border skirmishes or momentary conflicts. It involves sovereign nations, which rules out civil wars and riots. Also a nation fights a nation and not a particular individual or group in a nation. Force of arms excludes for example trade embargoes and blockades. These make up the basic components of a war.

Origin of the "Just War"

Most authors agree that "St. Augustine was the originator of the Just War Theory."(2) When it came to individual self-defense, St. Augustine contended that one's own life or property was never a justification for killing one's neighbor. Christian charity was the motivating force behind this statement. But when one speaks of rulers of nations they have the obligation to maintain peace. This obligation gives them the right to wage war. He says, "'The natural order conducive to peace among mortals demands that the power to declare and counsel war should be in the hands of those who hold the supreme authority.'"(3) Those subject to the rulers must obey unless they command something against a Divine Law. For St. Augustine the only reason for waging a war would be to defend the nation's peace against serious injury. He says, "'A just war is wont to be described as one that avenges wrongs, when a nation or state has to be punished, for refusing to make amends for the wrongs inflicted by its subjects, or to restore what it has seized unjustly.'"(4) The intention of the war is very important for St. Augustine. He says, "'The passion for inflicting harm, the cruel thirst for vengeance, an unpacific and relentless spirit, the fever of revolt, the lust of power, and such things, all these are rightly condemned in war.'"(5) St. Augustine emphasizes the idea of restoration of peace as the main motive of war. He says, "'We do not seek peace in order to be at war, but we go to war that we may have peace. Be peaceful, therefore, in warring, so that you may vanquish those whom you war against, and bring them to the prosperity of peace.'"(6) So in St. Augustine's thinking a war "was limited by its purpose, its authority and its conduct."(7)

Further Developments - St. Thomas Aquinas and the Middle Ages

A great impetus to the Just War Theory was St. Thomas Aquinas. He emphasized St. Augustine's statements about war and added a little to them. He followed a similar reasoning breaking up his argument into three necessary conditions for a just war: authorized authority, just cause and rightful intention. In speaking about who authorizes war St. Thomas emphasizes that the sovereign has the responsibility for the common good of those committed to his care. Only he can declare war. Moreover the sovereign has the lawful right of recourse to "the sword" to defend his people against internal strife by punishing those who do evil, justified by St. Paul in verse 4 of chapter 13 in the letter to the Romans. Therefore it is his duty to defend the common good against external enemies by having recourse to arms. A just cause is required to wage war. St. Thomas considers such a cause to be "that those who are attacked, should be attacked because they deserve it on account of some fault."(8) Finally St. Thomas discusses the right intention for waging war. Only two possibilities are presented: either the furthering of some good or an avoidance of some evil. The underpinnings of his arguments and most important contribution to St. Augustine's theory "would appear to consist in his stress on the natural law."(9)

The Middle Ages were occupied mostly with the right to wage war and restoring peace through mercy and justice. After St. Thomas other authors on a just war such as St. Ramon of Penafort just elaborated on his position. They mainly concentrated on specifying the proper authority, just causes and intentions of St. Thomas.

A Fully Developed Theory

Although St. Augustine introduced the idea of a just war and the Middle Ages furthered its cause, it was not until the 16th and 17th centuries that a complete theory, which included the proper waging of a war, was established. Two names of importance regarding this development are Vitoria and Suarez. Fr. Conway, S.J., has synthesized their teaching. Hostilities are divided into two classes: an armed attack against a peaceful society and injurious actions taken against the same (generally defined as an infringement of a right). The first class from which an armed response resulted would be considered as a defensive war. This type of war was distinguished from the second class hostility. An armed response to an injurious action was considered an offensive or aggressive war. According to Vitoria and Suarez a defensive war needed "no special moral justification."(10) They saw an armed response as an involuntary act forced upon a nation. On the other hand, the aggressive war needed to be justified. An injurious action done does not involve destruction and death so how was it possible for the Christian willfully to choose war as a response? The problem for them arose from the conflict between a Christian wanting love and peace but responding with death and destruction. So they proposed conditions under which a Christian could respond to injurious action while preserving Christian values. So for them the just war conditions only apply to aggressive wars. The three conditions of St. Thomas are retained by them in their theory. But they added two more: the war must be fought as a last resort and in a proper manner (without killing the innocent).

Following the conditions outlined above moral theologians have tried to define them more explicitly. Regarding an injurious act it was taught that "only an injury so grave that it outweighs the risks and losses of war is a justification for making war" following the principle of double effect.(11) If such a weighty injury does not exist then in charity one would have to tolerate the injustice. What are sufficient causes for war? "Grave injury to the honor of a nation. . .to the natural right of the nation. . .to the rights of the nation under positive law."(12) Examples of injury to honor would be insulting a ruler or ambassador. Natural right injuries would include a nation's existence, property or freedom within their own nation. Violations of positive law would include breaking international agreements or treaties. Injury done to another nation can be grounds for entering into a war especially if one is allied to them or out of charity to protect them from a stronger aggressive nation.

The idea of war being fought in a proper manner means that not all is fair to do in war. Three main areas of discussion here are violent acts done against things connected with religion, against people and against property.

Sacred places such as churches are not to be harmed unless there is a real military necessity. A church could be used for military purposes and thus becomes a target of attack. Also it may happen that a church is next to some military target and unintentionally is harmed by attacking it. Apart from these circumstances they cannot be attacked.

People during war can be divided into various categories. Combatants are "all those who are engaged in the actual promotion of war."(13) Direct combatants are the fighters themselves. Indirect combatants are the unarmed helpers of the soldiers in military ways such as transporters of supplies, weapons producers, etc. Noncombatants are those people who are members of the enemy nation that are chaplains, medical personnel and civilians. Also there are neutral people who are not part of either warring party and are not involved in the hostilities. The killing or wounding of enemy combatants falls under the natural law idea of self-defense. The indirect killing of non-combatants or neutrals is permissible according to the principle of double effect. But such killing must be unintentional and unavoidable. Direct killing of such people is murder, that is, when it is intentional and avoidable.

The military property of one's enemy can be confiscated or destroyed just as one can do so against an unjust aggressor. Public, non-military property may be occupied or movable goods can be appropriated. Private property both movable and immovable must be respected and only taken for some necessary purpose of war.

These are the main amplifications and developments of the conditions outlined for a just war. There are other considerations that moralists have made but it is not our purpose to give an exhaustive analysis of it.

Arguments For a Just War

As we have already seen St. Augustine argues from the natural order of peace to the right of rulers to declare war to maintain it. St. Thomas also sees the justification for war in the natural order but stresses more the common good of the people. Scriptural passages are used to defend the just war. St. Thomas cites another's commentary on the centurion that states, "'If the Christian Religion forbade war altogether, those who sought salutary advice in the Gospel would rather have been counselled to cast aside their arms, and to give up soldiering altogether. . .If he (St. John the Baptist) commanded them to be content with their pay, he did not forbid soldiering.'"(14) St. Thomas argues that St. Paul, as already mentioned, gives those in authority the right to punish by the sword disturbers of their commonwealth's internal peace. Therefore it is also their duty to use arms against a commonwealth's external enemies.

St. Thomas puts forward some counter arguments to war and refutes them. The first argument says that God only punishes the sinner. Therefore when Our Lord told St. Peter that he who takes the sword will perish by it all wars would be unlawful. To counter this argument St. Thomas quotes St. Augustine who says that taking the sword is to be understood as arming oneself to kill another without the permission of authority. In war the sword is taken with permission. The second argument refers to the Divine precept not to resist evil. St. Augustine is referred to as saying such a precept is to be always kept in mind and when necessary put into practice. On the other hand, sometimes it is necessary, St. Thomas says, to act differently for the sake of the common good or the good of those one is fighting. Quoting St. Augustine a reference is made to sometimes having to punish people with a kindly severity even against their will to strip them of their sins. Finally an argument is put forward that sin is contrary to virtue. Since peace is a virtue and war is contrary to it therefore it must be a sin. St. Thomas answers this similar to St. Augustine's thought that the purpose of war is to bring about peace. Therefore it is not contrary to it. (Click here for the full text of St. Thomas' Arguments in the Summa)

A more modern author cites Melchisedech blessing Abraham when he returns from a victorious war against four kings as an example that war is "under the law of nature".(15) (Gen. 15; 18-20) God in the Old Testament "many times ordered or approved of war, as can be seen from Exodus and following books in numerous places."(16) In the New Testament a centurion was praised by Our Lord. (Matt. 8,10) Our Lord used physical force against those doing evil. (Jn. 2,15) Cornelius a centurion is called a devout and God-fearing man. (Acts 10,2) St. Paul praises warriors in the Old Testament such as Gideon, Barac, Samson, etc. (Heb. 11; 32-34) All these passages are seen as examples of God condoning war.

Regarding the Church the same author says she has never condemned war. The Church has always promoted peace and tried to lessen the evils of war. Official declarations, Fathers and Doctors of the Church have recognized that war is not necessarily sinful. The Church from necessity has even promoted wars such as the Crusades and approved of military orders. Even soldiers such as Martin of Tours have been declared saints.

In discussing the natural law, this author argues from individual rights to those of the State. Since an individual can defend himself against unjust aggression so can the State. An individual is allowed to seek justice for an injury or loss therefore the State can use force to compel another nation to make reparation. These are some, although I'm sure not all, of the arguments for a just war.

Arguments Against a Just War

"The basic lines of objection to relying on just-war theory seem to me to come down to three points: first, the pacifist thesis that the theory is theologically unacceptable and is incompatible with basic Christian values; second, the view that the theory effectively leaves out of consideration some aspects of either the particular situation or the general character of modern warfare that need to be considered if a satisfactory and conclusive verdict on the morality of a given war is to be reached; third, the view that the theory contains so many indeterminate elements and potentially contradictory considerations that we should not be surprised that applying it does not yield a determinate result."(17)

First let us look at some of the pacifist arguments against all war. Starting with the Bible they make the case that in the days of Jesus the idea of loving one's neighbors but hating one's enemies seems to have been an accepted principle. Jesus clearly rejects and replaces this with loving one's enemies. (cf. Mt. 5:43,44) The Old Testament had established love between neighbors but according to Ronald Musto, "Christ establishes a New Law; he builds upon the old in a moral progression. Not only is one not to resist one's enemies, but one is to love them. This love applies not only to one's personal enemies but to public enemies and potential foes in battle. Ecthros, the Greek word for enemy, is used in the New Testament for both."(18) So those in favor of total pacifism undercut Old Testament argument for justifying war by seeing God as morally progressing His people toward the culminating point of the New Law. Also, they point out that is not so clear from the Greek whether Our Lord was addressing His statements to personal enemies or public one's .

Some promoters of war see much of the imagery in the New Testament as a support of war. Gerardo Zampaglione examined the "'imagery of violence in the New Testament and finds that in all cases it is used either allegorically or in parable form.'"(19) Violence in parables is never the main part of the story. The same author says that "'it is difficult to justify even the just, defensive war if one takes seriously the message of the Sermon on the Mount, which is the heart of the Gospel.'"(20)

Our Lord's driving out the money changers from the Temple is used to justify war by the righteous. Those against war claim that "there is no evidence of violence done to people. . . Christ's action does not show the force of war; rather the scourge is used to show His messianic role."(21) When Our Lord refers to no greater love than when one lays down one's life for a friend pro-war advocates use it to praise soldiers giving their life for their country. But to use the text in this way is to extract it from a call to love. "The purpose of the soldier is not to lay down his life, but to make the enemy lay down his."(22) The text of St. Paul that everyone must be subject to higher authorities is used to justify the State's right to require its citizens to kill in war. (cf. Rom. 13:1-7) This passage is seen by those against war to be pointing to the legitimate realm of police power in civil governments. Jean Lasserre and Richard McSorley, S.J., examine and explain the distinction between "indiscriminate violence of war and the legitimate function of the police who seek to contain violence and uphold the law."(23) The same authors "address the notion of violence done in the spirit of love and both reject it on scriptural grounds."(24) Jesus as our model rejected physical force and revenge that "led inevitably to His Passion and humiliating death on the Cross."(25)

St. Paul's writings reflect the spirit of the Gospel being lived by the Christian communities. He speaks of not rendering "evil for evil" but of overcoming it with good. (Rom. 12:17,21) The Martyrs of the pre-Constantine era are an example of Christian praxis in the face of violent opposition. It is "'the story of the successful Christian revolution against the Roman Empire,'" that is, nonviolence over violence.(26)

Regarding Christian military service "before the year 172 there was none. . .Evidence of Christians serving in the Roman army before the third century is suspect. . . A study of tombstone inscriptions reveals that only 7 Christians out of 4,700 extant inscriptions were members of the military."(27) This evidence shows few served in the military. Of the 7 military tombstone inscriptions it is not clear whether these people converted in the service or entered already converted. In 298 Marcellus, a centurion, refused to continue military service. In front of the Emperor he claimed he would only serve Jesus Christ. Brought to trial Marcellus argued that "he could not inflict wounds."(28) He was executed for defying the Emperor. In the third century "Christians certainly served in the army; but their numbers were small, their service peaceful, and their testimony one of peace and not of violence."(29)

When we arrive at St. Augustine his justifications for war "are based on Cicero and other Roman thinkers. . . (with) Manichaean and Neoplatonic influences."(30) There is a dualism in his writings over the possibility "to love an enemy internally and still to kill him."(31) St. Augustine "seems never to have satisfied himself as to how it (war) is fully compatible with Christian charity."(32)

During the Middle Ages while the Just War Theory was becoming more developed and Crusades were being preached peace movements among Christians flourished, also. St. Francis "may not have been a pacifist, but 'he lived as if he were.'"(33) A peace movement known as the "Great Alleluia" involving thousands of people took place in northern Italy in the 13th century. In 1233 the movement had grown to such proportions that 400,000 people gathered to demonstrate for peace and reconciliation. Another Italian peace movement known as the "Bianchi" moved about in thousands from city to city. Peacemaking was their major work. One chronicler notes that by the time one of these processions reached Rome its numbers had swelled to 200,000.

Another approach to condemnation of war that began to develop at this time was a distinction between war in the abstract and the reality of war. These thinkers say that while one can hold to war as justified in theory, in practice it cannot be justified. In the 16th century St. Thomas More was such a thinker. In his "Utopia," or ideal society, St. Thomas allowed for war only as a defensive measure. But "in reality no war that he knew in history, in the present, or in the foreseeable future was just."(34) So St. Thomas More used the Just War in theory to condemn all wars in reality.

Some modern authors use the same approach. Fr. Emmanuel McCarthy says that he has "found no war that has ever been fought according to the moral norms of the Just War Theory. . .(and) cannot imagine a war that could be conducted within its moral perimeters."(35)

To sum up what lies behind many Pacifist claims is this: "war's central action of inflicting suffering and death is directly opposed to the example of Christ in enduring these same realities. . .(it) conflicts with the essence of the Gospel."(36) The Just War Theory is looked upon by them as a compromise to Christian ethics introduced during the Constantine era when the Church became identified with the Roman Empire. These are some of the arguments presented by Pacifists but in no way is it an exhaustive list.

Modern Warfare

As we move into the modern age warfare of massive destruction capabilities Pacifists see Christian thought returning full circle to the absolute pacifism of the primitive Church. We begin with World War I and Pope Benedict XV. This Pope made very strong statements against war. "Benedict opposed war in any form and rejected the theory of the just war as historically outmoded and theologically inadequate."(37) Further he rejected the distinction made between public and private morality. "'The Gospel has not one law of charity for individuals and another for states and nations, for these are but collections of individuals.'"(38) Pope Benedict first statement could be placed under the argument against the Just War Theory on grounds of insufficiency in modern warfare.

World War II with its atomic capabilities changed the perspective on the just war. Pope Pius XII modified the traditional teaching of warfare by saying that, "the enormous violence of modern warfare means that it can no longer be regarded as a reasonable, proportionate means for settling conflicts."(39) Regarding a question posed to him about a self-defensive use of ABC (Atomic-Bacteriological-Chemical) warfare this Pope answered by referring to "the same principles which are today decisive for permitting war in general."(40) Notice that the Pope is here making a reference to the Just War Theory. Pope John XXIII's encyclical "Pacem in Terris" seems to have condemned aggressive or offensive war when he stated, "'Therefore in this age of ours, which prides itself on its atomic power, it is irrational to think that war is a proper way to obtain justice for violated rights.'"(41) This Pope says that a proportional injury does not exist anymore to justify war. If the Just War historical account is true, the Pope in condemning the offensive or aggressive war at the same time eliminated the Just War Theory, as it applies only to that type of war (not a defensive one), as set forth by Vitoria and Suarez!

It is interesting to follow Vatican II's teachings on this issue. In "Gaudium et Spes" the document stresses that modern weapons lead to atrocities in war far exceeding any known before. Also, the complexity of international relations can make an incipient war develop into full-scale war. Modern weapons "can inflict immense and indiscriminate havoc which goes far beyond the bounds of legitimate defense."(42) Because of this reality total warfare is most definitely condemned following Pope John XXIII's and Pope Paul VI's statements on this matter. Also, modern weapons are seen by the Council as not even justified in a defensive war with their indiscriminate destruction.

On the other hand, not all warfare is condemned. The Council justified "the right of a nation to defend itself by a discriminate and proportionate use of force as a last resort."(43) The Council does not mention the Just War Theory but uses some themes recognizable from it such as: 1. War is to be used only after all efforts for peace have failed. 2. Government leaders have the duty to protect their people's interests - the common good. 3. A right intention rules out force being used for political or military objectives. 4. Not all is fair during war. 5. Indiscriminate killing of the innocent is prohibited.

So after the Council the idea of war comes down to this: "war is not morally justifiable . . .to punish an offense or. . .to recover a thing, but is justifiable only. . .to repel injury and aggression."(44) Any strategy with the intention of attacking cities or large areas along with their populations cannot be morally tolerated, even as a last resort.

Further developments among Bishops and Popes to the present involve a Catholic policy where nuclear deterrence can only be a temporary solution. The Catholic goal is to de-nuclearize the world. Arms control, even as an important contribution to present day problems, is not enough. Only a strategy that tends toward disarmament is an acceptable strategy for the Church.

Two principles from the Just War Theory stand out in all of this modern day analysis. War is limited by the immunity of noncombatants and the general principle of proportionality. The former limits the widespread destruction of ABC warfare. The latter even limits legitimate self-defense.

The relatively recent Gulf War provided moralists with a modern day war example to analyze. Francis Winters claimed that "on balance the theory failed the test of providing wise judgment."(45) Another author thought the theory could be applied to it with some adaptations. Although at the same time he recognized a "serious problem in how we understand and apply the notion of noncombatant immunity. . .(and that) the principle of proportionality is all too likely to raise large questions that require political judgments and do not yield definite answers."(46) These problems of applying the theory would seem to point to the argument already mentioned that the Just War Theory cannot yield a determinate result.

The modern war debate is far from over. Some talk of a limited nuclear war. Others claim that the limitation of war is impossible. One thing is for sure - if the limited war people are wrong the destruction of the world will end the debate!


In this investigation we have tried to provide a general survey of the history of the Just War Theory with some of the arguments for and against it. As we have seen St. Augustine is considered the originator of the theory. St. Thomas Aquinas and other Middle Age authors further clarified its justification. The proper authority, just causes and intentions for waging a just war were further elaborated on at this time. Victoria and Suarez in the 16th and 17th centuries fully developed the Just War Theory. They distinguished between offensive and defensive wars. Also they added two more conditions to the theory: war as a last resort and the proper manner of fighting a war. From there we move into the modern age of warfare with its potential for massive destruction. The Popes of this World War century rule out aggressive wars leaving only defensive wars. The principles of proportionality and immunity of noncombatants are an important contribution of the Just War Theory to the modern situation. Whether or not the theory itself is still applicable to war at present is still being debated.

On the question of the justification of war different arguments are put forward. Both the Old and New Testament are used to show war is not against the will of God. Also of importance related with this is the special authority given to government leaders to safeguard the natural order and the common good. Another argument put forward is to reason from the rights of the individual to those of the State. Finally an appeal is made to the history, teaching and practice of the Church.

Those against war argue mainly from Sacred Scripture, especially the New Testament. The main claim made is that Jesus taught and lived a nonviolent position. St. Paul and the primitive Church continued this tradition. The Constantinian era compromised Christian thought by identifying the Church with the State. Nevertheless, examples of pacifist movements can be seen in later Church history. A different form of argument especially brought forward with St. Thomas More is the possibility of a just war in theory but impossible in reality. Others attack a Just War Theory as irrelevant in modern warfare. Still others claim the theory is useless in coming to conclusions.

Certainly this issue is relevant and important in our modern era. While we debate other moral questions the threat of the gravest moral evil constantly hangs over our heads - the suicide of mankind. Fortunately even if the war issue cannot be resolved at least the Just War Theory provides a limiting factor. Also, efforts are being made to eliminate ABC warfare and promote peace. Certainly more people need to see the urgency of this issue for our modern world.

Author's Note: For the latest word on the issue of war see the Catechism of the Catholic Church, paragraphs 2307 through 2317. Also, see the United States Conference of Catholic Bishops statement on Just War, "The Harvest of Justice Is Sown in Peace" and on the present Iraq War "Iraq: The Way to Peace: Resources for Diocese and Parishes."


1. John A. McHugh, O.P. and Charles J. Callan, O.P., Moral Theology: A Complete Course, vol. 1 (New York: Joseph F. Wagner, 1929), 545.

2. The New Catholic Encyclopedia (New York: McGraw-Hill, 1967) vol. 14. "Morality of War," by R. A. McCormick, 803.

3. Thomas Aquinas, Summa Theologica, vol. 3, IIaIIaeQQ. 1-148, trans. by the Fathers of the English Dominican Province (Westminster, Maryland: Christian Classics, 1981), 1354.

4. Ibid.

5. Ibid.

6. Ibid.

7. New Catholic Encyclopedia, 803.

8. Aquinas, 1354.

9. New Catholic Encyclopedia, 803.

10. Ibid.

11. McHugh, 549.

12. Ibid.

13. Ibid, 556.

14. Aquinas, 1353.

15. McHugh, 546.

16. Ibid.

17. Langan, John, S.J., "The Just War Theory After the Gulf War," Theological Studies, vol. 53, no. 1 (March, 1992): 99.

18. Musto, Ronald G., The Catholic Peace Tradition (Maryknoll, New York: Orbis Books, 1986), 24.

19. Ibid, 28.

20. Ibid.

21. Ibid, 29.

22. Ibid.

23. Ibid, 28.

24. Ibid.

25. Ibid, 26.

26. Ibid, 41.

27. Ibid, 41-42.

28. Ibid, 44.

29. Ibid.

30. Ibid, 48.

31. Ibid.

32. New Catholic Encyclopedia, 803.

33. Musto, 83.

34. Ibid, 132.

35. McCarthy, Rev. Emmanuel Charles, Just War Theory: The Lethal Mirage of Christian Morality (Baxter, Minnesota: Center for Christian Nonviolence, n.d.), 11-12.

36. Douglass, James W., The Non-Violent Cross: A Theology of Revolution and Peace (New York: The Macmillan Company, 1968), 177-178.

37. Musto, 171.

38. Ibid.

39. New Catholic Encyclopedia, 803.

40. Ibid, 804.

41. Flannery, Austin, O.P., ed., Gaudium et Spes, in Vatican Council II: The Conciliar and Post Conciliar Documents (Collegeville, Minnesota: The Liturgical Press, 1975), 989.

42. Ibid.

43. Wicker, Brian, War and the Nuclear Dilemma, in Modern Catholicism: Vatican II and After, ed. by Adrian Hastings (New York: Oxford University Press, 1991), 303.

44. New Catholic Encyclopedia, 804.

45. Langan, 99.

46. Ibid, 109-110.


The New Catholic Encyclopedia. New York: McGraw-Hill, 1967. Vol. 14. "Morality of War," by R. A. McCormick.

Aquinas, Thomas. Summa Theologica. Vol. 3, IIaIIaeQQ. 1-148. Translated by the Fathers of the English Dominican Province. Westminster, Maryland: Christian Classics, 1981.

Douglass, James W. The Non-Violent Cross: A Theology of Revolution and Peace. New York: The Macmillan Company, 1968.

Farrell, Walter, O.P. A Companion to the Summa. Vol. 3, The Fulness of Life. New York: Sheed & Ward, 1940.

Flannery, Austin, O.P., ed. Gaudium et Spes, In Vatican Council II: The Conciliar and Post Conciliar Documents. Collegeville, Minnesota: The Liturgical Press, 1975.

Glenn, Paul J. A Tour of the Summa. Rockford, Illinois: Tan Books and Publishers, 1978.

Langan, John, S.J. "The Just War Theory After the Gulf War." Theological Studies Vol. 53, No. 1 (March 1992): 95-112.

McCarthy, Rev. Emmanuel Charles. Just War Theory: The Lethal Mirage of Christian Morality. Baxter, Minnesota: Center for Christian Nonviolence, n.d.

McHugh, John A., O.P. and Charles J. Callan, O.P. Moral Theology: A Complete Course. Vol. 1. New York: Joseph F. Wagner, 1929.

Musto, Ronald G. The Catholic Peace Tradition. Maryknoll, New York: Orbis Books, 1986

U.S. Catholic Conference. A Report on The Challenge of Peace and Policy Developments 1983-1988. Washington, D.C., 1988.

Wicker, Brian. War and the Nuclear Dilemma. In Modern Catholicism: Vatican II and After. Edited by Adrian Hastings. New York: Oxford University Press, 1991.

Zahn, Gordon. "Total War and 'Absolute' Pacifism." Concilium Number 184, Year 19 (April 1983): 26-30.