Just War Theory & Terrorism
This article on just war and terrorism first appeared in the Summer 2016 issue of Providence’s print edition last August. To read the original in a PDF format, click here. To receive future issues of the print edition before some of their articles appear online, click here.
In a classic scene in Monty Python & The Holy Grail, King Arthur is attacked by the Black Knight, who takes it upon himself to oppose anyone attempting to cross a certain bridge. In the course of the battle that follows, Arthur cuts off the Black Knight’s appendages one by one while his opponent famously retorts, “Just a flesh wound…come back you pansy, I’ll bite your legs off!”
Significantly, the Black Knight is brazen in flouting the law. He is not sneaky, but rather openly challenges the rule of law–as do pirates, brigands, and those we today call “terrorists.” He is not simply a discrete danger to the citizen who wants to cross the bridge. Rather, he calls into question the foundation of civilized life: a social contract wherein security is guaranteed by the sword in the hands of agents of the state, and citizens do not engage in violence. The work of the Black Knight tears at the social fabric of community, endangering both individuals and institutions.
What does Arthur represent in this scene? He symbolizes, beyond the hilarity, the rule of law and the imperatives of political order. If Arthur did not deal with the Black Knight, who would? If the king, if the state, does not impose order in his realm, who else can? How else can justice be promoted? If no Arthur, what would happen to the next peasant who needed to use that bridge for commerce? Would the King of the Britons show more love of neighbor by ignoring the Black Knight (“he is not my problem”) or by promoting the rule of law?
The Christian just war tradition provides answers to these questions. Mainstream Christian thought, from St. Paul (Romans 13) to early church fathers like Ambrose and Augustine, and all major Christian traditions (Catholic, Orthodox, Lutheran, Reformed, Anglican, Baptist(s), and their progeny) take some form of just war thinking as the normal and normative position for Christians when considering these issues. This essay provides a brief overview of the just war tradition and then applies the framework to the problem of contemporary terrorism.
What is Just War Theory?
The classical just war framework provides the foundation for customary international law as well as the formal laws of armed conflict, in addition to ethical reflection. Just war thinking begins with three criteria for the just decision (jus ad bellum) to use military force: legitimate authority acting on a just cause with right intent. Practical, secondary jus ad bellum considerations include: likelihood of success, proportionality of ends, and last resort. Just war thinking also has criteria regarding how war is conducted (jus in bello): using means and tactics proportionate (proportionality) to battlefield objectives and which limit harm to civilians, other non-combatants, and property (discrimination).
More specifically, political actors should carefully examine the following principles when considering the implementation of military force:
Jus Ad Bellum
- Legitimate Authority: Supreme political authorities are morally responsible for the security of their constituents, and therefore are obligated to make decisions about war and peace.
- Just Cause: Self-defense of citizens’ lives, livelihoods, and way of life are typically just causes; more generally speaking, the cause is likely just if it rights a past wrong, punishes wrong-doers, or prevents further wrong.
- Right Intent: Political motivations are subject to ethical scrutiny; violence intended for the purpose of order, justice, and ultimate conciliation is just, whereas violence for the sake of hatred, revenge, and destruction is not just.
- Likelihood of Success: Political leaders should consider whether or not their action will make a difference in real-world outcomes. This principle is subject to context and judgment, because it may be appropriate to act despite a low likelihood of success (e.g. against local genocide). Conversely, it may be inappropriate to act due to low efficacy despite the compelling nature of the case.
- Proportionality of Ends: Does the preferred outcome justify, in terms of the cost in lives and material resources, this course of action?
- Last Resort: Have traditional diplomatic and other efforts been reasonably employed in order to avoid outright bloodshed?
Jus In Bello
- Proportionality: Are the battlefield tools and tactics employed proportionate to battlefield objectives?
- Discrimination: Has care been taken to reasonably protect the lives and property of legitimate non-combatants?
Classical just war thinkers, such as Cicero and Augustine, have long held that the end of a just war is peace. Over the past decade, some scholars have fleshed out a jus post bellum to give ethical and policy direction to this affirmation. In earlier books I articulate three principles of jus post bellum:
Jus Post Bellum
- Order: Beginning with existential security, a sovereign government extends its roots through the maturation of government capacity in the military (traditional security), governance (domestic politics), and international security dimensions.
- Justice: Getting one’s ‘just desserts,’ including consideration of individual punishment and restitution policies when appropriate for those who violated the law of armed conflict.
- Conciliation: Coming to terms with the past so that parties can imagine and move forward toward a shared future.
Excellent volumes have been written on the history of just war thinking, making a full recitation here unnecessary. Worth highlighting is a recent volume by Professor J. Daryl Charles and former U.S. Navy chaplain Timothy Demy answers hundreds of questions—citing dozens of historical Christian texts—about the ethics of war from a Christian perspective. In this volume the authors look carefully at the earliest extant Christian writers, such as Polycarp, Origen, Tertullian, and Eusebius on questions of government and the military. These thinkers have been wrongly identified as “pacifists.” As Charles and Demy demonstrate, the early Christian writers were more concerned with the pagan religious duties that Roman magistrates and soldiers had to perform as part of their everyday jobs, including kneeling to idols, acknowledging the deity of the emperor, participating in various sacral feasts and ceremonies, and the like. The second- and third-century church was deeply concerned about these activities as idol worship rather than questioning the efficacy of just magistrates, police, and security personnel.
Charles and Demy, and a fresh book by Nigel Biggar, are among the best reminders that Christianity has two millennia of teaching on government and the use of force, and today’s Christians should start their deliberations with modest and intent study on what the Bible and the great churchmen of the past have to say on these issues. The most important of such authors, one cited as an authority by not only Catholic and Orthodox political theorists and churchmen but also by Luther and Calvin as authoritative, is Augustine, Bishop of Hippo.
Augustine (354-430 A.D.) traveled across the Roman world and saw the glories and perversions of Imperial Rome. As a Christian faced with both Pax Romana as well as the cruelties of the arena, Augustine pondered the conditions for when it was just to employ violence in political life. Augustine’s formulation of the just use of force relied heavily on the notion of caritas, or charity: “love your neighbor as yourself.” In domestic society as well as international life, how does one go about loving one’s neighbor? Augustine argued that within society adherence to the rule of law, including punishment of lawbreakers, is a way of loving one’s neighbors. To love one’s neighbors includes refraining from harming them and supporting the authorities in their efforts to provide security to the citizenry. Moreover, Augustine noted, caritas means protecting one’s neighbor when they are attacked, even if one is forced to employ violence to protect that individual. Augustine used Romans 13:1-5 to argue that sovereign authorities have a responsibility to order and to promote justice, including the use of the sword:
Let every soul be subject unto the higher powers. For there is no power but of God: the powers that be are ordained of God. Whosoever therefore resists the power, resists the ordinance of God: and they that resist shall receive to themselves damnation. For rulers are not a terror to good works, but to evil. Wilt thou then not be afraid of the power? Do that which is good, and thou shalt have praise of the same. For he [the government official] is the minister of God to thee for good. But if thou do that which is evil, be afraid. For he beareth not the sword in vain: for he is the minister of God, a revenger to execute wrath upon him that doeth evil. Wherefore ye must needs be subject, not only for wrath, but also for conscience sake.
Augustine suggested that this is also true with regards to foreign threats: loving our neighbor can mean self-defense of the polity. Likewise, loving our foreign neighbors may mean using force to punish evildoers or right a wrong. He writes, “true 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.”
In addition to caritas, Augustine’s writings suggest a second reason for jus ad bellum: order. Augustine consistently privileged political order over disorder. The Augustinian conception of the universe is one in which God is the ultimate Creator, Judge, Arbiter, and End. Although God allows sin and imperfection in this world, he nonetheless sustains the universe with a divine order. This order is mirrored in society by the political order with its laws and hierarchy. Augustine argued that although the City of Man is a poor reflection of the City of God, nonetheless it is the political principle of temporal order which most approximates the eternal order. During his lifetime, Augustine witnessed the alternative: the looting of Rome and ultimately the sacking of his home in North Africa in the final days of his life. His fear of political disorder was more than a distaste for regime change; it was dread of losing civic order with all of its attendant moral duties and opportunities.
Today, many Christians want to focus on the law of love but neglect Augustine’s presupposition that political order is the foundation for society. Augustine’s argument is that the state has a responsibility to both domestic and international security—a responsibility that it must uphold, even if the state dirties its hands in the process of securing the realm.
Augustine’s intellectual heir was Thomas Aquinas (1225-1274), who similarly argued that a war was just when it met three requirements: sovereign authority, just cause, and right intent. It is noteworthy that Aquinas began not with just cause or right intent, but with a focus on sovereign authority:
In order for a war to be just, three things are necessary. First, the authority of the sovereign by whose command the war is to be waged. For it is not the business of a private individual to declare war…And as the care of the common weal is committed to those who are in authority, it is their business to watch over the common weal of the city, kingdom or province subject to them. And just as it is lawful for them to have recourse to the sword in defending that common weal against internal disturbances, when they punish evil-doers… so too, it is their business to have recourse to the sword of war in defending the common weal against external enemies.
Aquinas saw most violence as criminal and lawless. The fundamental purpose of the state was to provide a counterpoise to lawlessness. He also argued that states should be concerned with just cause. He writes: “Secondly, a just cause is required, namely that those who are attacked, should be attacked because they deserve it on account of some fault.” He quotes Augustine, “Wherefore Augustine 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.’” Aquinas’ conception of just cause is richer than the contemporary debate on self-defense because it includes punishing wrongdoing and restitution of some sort to victims. Indeed, it seems that Aquinas’ just cause would support the use of force to curb aggressive non-state actors, protect individual human life via humanitarian intervention, and punish rogue regimes that disrupt the international status quo.
Finally, Aquinas said that the just resort to force required just intent. Scholars and churchmen alike have long pointed out the dilemmas of ascertaining right intent. For the average soldier, the medievals solved this problem by providing absolution to their troops before battle and sometimes providing it again after the battle for the survivors. This did not completely solve the problem of rage and bloodlust on the battlefield, but rather sought a spiritual solution to a very human dynamic.
However, this says little about the sovereign’s motivation. Contemporary politics makes the situation even more complex because most state decisions are not made by a sovereign individual such as a king or empress. Western governments are pluralistic, representing multiple voices and acting based on a complicated set of interests and ideals. However, Aquinas’ focus on right intent did not necessarily call for agonizing over one’s ethical motivations. He writes, “It is necessary that the belligerents should have a rightful intention, so that they intend the advancement of good, or the avoidance of evil.” In other words, Aquinas’ idea of right intent is that states should seek to advance the security of their people and avoid wars based only on greed or vengeance. Aquinas again cites the Bishop of Hippo: “Hence Augustine 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 like things, all these are rightly condemned in war.’” Aquinas would likely agree that in contemporary international politics, the right intent of states is to seek their own security and then promote human flourishing around the world.
It is beyond the scope of this essay to deal with all of the great Christian thinkers and their views on the ethics of war, but nearly every question conceivable about the ethics of armed conflict and the responsibilities of the individual and the state can be found within the Christian intellectual tradition: Aquinas on self-defense against the Turks; Vitoria and Suarez criticizing Spanish treatment of native people in the New World; Hugo Grotius articulating an international law outside of ecclesiastical mandates; Martin Luther and John Calvin on the importance of a robust state and the ethics of self-defense; and others in our own time, most notably Paul Ramsey on just war in the nuclear age and Jean Bethke Elshtain’s recent work on gross human rights violations and the possibilities of justice and forgiveness. All of this work is the heritage of modern Christians, and is worthy of our reference.
At the same time, it is noteworthy that the development of all the great Christian denominations explicitly assert just war thinking in some form. For most of the past two millennia, the Roman Catholic Church has clearly supported just war. The Catechism of the Catholic Church (sections 2302-2317) begins with the distinction between “murder,” rooted in “unjust anger” and “hatred,” and “righteous anger” or what we might call “righteous indignation.” The Catholic Catechism emphasizes that the goal for political authorities must be peace, but that the “tranquility of order” described by Augustine often requires prevention of wrong, righting of past wrongs, and punishment of wrong-doers motivated by neighbor-love. These basic arguments are largely accepted within the autocephalous Orthodox churches, although their trajectory since the sixth century, A.D. has been somewhat different. Like the Roman Catholic Church, Orthodoxy has recognized a pacific vocation for a group of “professional” religious individuals (e.g. monks, priests) but recognized the importance of the state in protecting the public. This self-defensive posture was particularly important as Constantinople (Byzantium) faced assault after assault by Muslim armies over the centuries and was later taken up by national Orthodox churches.
Over the years, the just war tradition has become the classic statement of government responsibility for aspects of real-world neighbor love for Lutherans, all major Reformed churches, Anglicans and their descendants (e.g. Methodists), and the major Baptist denominations. Newcomers to the religious scene, such as twentieth-century Pentecostals and charismatics, typically follow the just war tradition if they have an organized statement on issues of war and peace.
Just War and Terrorism: The Fundamental Issues
From a just war perspective, there are at least two issues to be addressed at the outset when considering terrorism. The first is whether or not terroristic violence is moral. The second is what responsibility legitimate political authorities have with regards to terrorism. Later, the more consequential issue of actuating neighbor love in a fallen world will be addressed.
Just war thinking begins from the premise that legitimate political authorities can morally use force. By definition, terrorists do not meet this fundamental criteria. The terrorist employs violence outside the rule of law with political, theological, or philosophical purposes in mind. More specifically here, terrorism is the use of violence by non-state actors, usually against non-combatants and private property but also against state targets, intending, among other things, to terrorize the public and change government policy.
In fact, terrorism is not just outside rightful political authority—it is an assault upon it. Biblical teaching, including Romans 13 but also relevant examples from the Old Testament, reminds us that political order is a moral good. Terrorism undermines that order, limiting the reach of the rule of law and eroding public trust. It is not just unlawful: it is evil.
One need not go further in the just war criteria than the fundamental tenet of legitimate authority when considering terrorism immoral and unlawful. There is no “just cause” that can legitimize bombing malls, subways, and public buses. It is impossible to conceive an ethical “right intention” that deliberately targets houses of worship, grocery stores, and queues in front of public offices. There is no need to go further down the jus ad bellum checklist.
Some might object, “Isn’t it true that one man’s terrorist is another man’s freedom fighter?” It is important to note that this discussion is typically not a jus ad bellum conversation (the ethics of going to war) but a jus in bello one (the ethics of how war is fought). In other words, the debate is usually not about strategic claims (such as building a caliphate) but rather about tactics. To be direct, the answer to the question is, simply, “no.” True freedom fighters abide by the laws of armed conflict, even if they are insurgents or guerrillas. For instance, they may not have expensive, standardized uniforms, but legitimate freedom fighters wear a patch or insignia demonstrating their identity as an organized combatant organization. They make explicit, public political demands that correlate with justice, order, and peace. They have an organization and are under an authority. In just war terms, they accept at least two forms of authority. The first stems from customary international law and is now codified in the Geneva Conventions; the second is that they submit to some form of organized authority (i.e. “are under the command of a person responsible for his subordinates”).
One could fight an asymmetrical or unconventional war against a superior foe by attacking government agents and property without attempting to terrorize the general populace. We need look no further than the example of George Washington, who operated under civilian political authority (the Continental Congress). He enforced discipline on his un-professional troops. He forbade and punished theft, rape, and abuse of civilians. The Continental Army may have been many things, but it was clearly not terroristic.
Not only is terrorism morally illegitimate in terms of jus ad bellum criteria because it defies and destroys centers of political authority, but it is also repugnant in terms of jus in bello. Terrorism, as an operational strategy, typically attacks “soft” targets such as civilian population centers. In other words, terrorists follow a perverse form of reverse discrimination: they actively seek unprotected civilians, private property, and un-secured government locations upon which to wreak havoc. Furthermore, terrorists typically seek haven by hiding within the civilian population. By doing so, they not only violate the principles of ethical combat but they, wittingly or unwittingly, draw civilians into the battlespace. When civilians are killed because terrorists have gone underground among them, the moral responsibility for those deaths resides, at least in part, on the terrorist.
Few disagree that most terrorists have violated the basic rules of civilization and thus are war criminals and unlawful belligerents. What are governments to do? What are Christians serving the public good supposed to do?
Of course, one choice selected by a tiny minority of Christians over the centuries is the Anabaptist option—pray that secular authorities do a good job keeping the peace but avoid all other involvement so as to not dirty one’s hands. It is beyond the scope of this paper to go into the views of this minority within Christendom. Suffice it to say, most Christians for the past two millennia have felt this to be an irresponsible approach to Christian duty and vocation in the world and have chosen some form of just war thinking.
Conclusion: The Political Ethic of Neighbor Love
Enter here the fundamental Christian ethic, love. Christ made clear that the two greatest commandments were to love God and love one’s neighbor. How is the individual to actualize love? More importantly, in political and social relations, how are governments best able to employ love? Specifically, how do political authorities, how do law enforcement officials, how do soldiers, how do statesmen, how do leaders and public servants employ neighbor love in collective situations? How do you put love into practice in times of war and terror?
Crucially, the Just War tradition does not suggest that employing force is simply a lesser evil. It is popular to say that one cannot lead a nation and avoid dirty hands. Against this simplistic insistence, the just war tradition, takes a more profound, morally nuanced view. Just war moral analysis holds that there evil comes dirt comes in different kinds; it asserts that employing force, while tragic, can be a virtuous act that seeks the greatest possible good rather than lesser evils; and it recognizes that killing too comes in different kinds, as both common sense and common recognize in distinguishing murder from self-defense. It does all this, in part, by emphasizing the importance of intention, which allows it render distinctions between, say, righteous indignation and hatred as well as between justice and revenge. See Nigel Biggar’s essay in this issue for further elaboration on this.
Just War thinking also distinguishes between political authorities employing force and private citizens employing violence. These principles are rooted in both Old and New Testament models of governance that find expression in the Catholic Catechism and some Protestant theologies as “subsidiarity” or “sphere sovereignty” which hold that the government “sphere” has duties to law, security, and order. Thus, the use of force under certain conditions are an expression of sovereign responsibility. This leads another morally nuanced distinction: that between violence and force. A distinction with a difference, force is rightly caused, geared toward justified ends, and proportional, while violence is illegitimate, deployed toward unjustified ends, and employed by those without sovereign mandate. Force, in the context of military power, is employed by those responding to sufficiently grave evils with an eye toward the restoration of justice and the hope of peace and reconciliation.
What this amounts to is the claim that, in the end, just war thinking is really is about “neighbor love.” The best way, sometimes the only way, to operationalize neighbor love in the real world of limits, fallenness, and evil is by standing between the beast and their prey, employing force against those who intend the innocent harm, and by standing for justice in the face of its assault.
Eric Patterson, Ph.D. is Dean and Professor in the Robertson School of Government at Regent University in Virginia Beach, VA. He is the author or editor of 11 books, including Ending Wars Well, Ethics Beyond War’s End, and Debating the War of Ideas.
Photo Credit: Shapes of Fear by Maynard Dixon, 1930 – 1932. Source: Smithsonian American Art Museum. Through the deft collusion of imagery, color, and mood, this allegorical representation produces the uneasy suspense of unsettling expectation. Though an analogous collusion of repetition of atrocity, perpetual threat, and theatrical violence, terrorists use savagery as spectacle to instill fear, paranoia, hyper-vigilance, and continued unease.
 I have previously used this point in a chapter, from which some of this material derived. See Eric Patterson, “Just War Theory: Christian Thinking on Justice and Security” in David Gushee, ed., Evangelical Peacebuilding (Eugene, OR: Wipf and Stock, 2013).
 This formulation derives from Augustine, as recorded in Aquinas’ Summa Theologica. Question 40, Secunda Secundae (New York: Christian Classics, 1981).
Two of the best are Frederick H. Russell, The Just War in the Middle Ages (Cambridge: Cambridge University Press, 1975) and James Turner Johnson, The Just War Tradition and the Restraint of War (Princeton: Princeton University Press, 1981).
J. Daryl Charles and Timothy Demy, War, Peace, and Christianity (Crossway, Wheaton, 2010)
 Nigel Biggar, In Defence of War (Oxford, Oxford University Press, 2014).
 This famous quote from Augustine is referred to in Aquinas’ statement following Objection 4. Summa Theologica, Part II, II, Question 40.
 Roger Epp, “The Augustinian Moment in International Politics,” International Politics Research Papers, No. 10 (Aberystwyth, UK: Department of International Politics, University College of Wales, 1991).
 This debate—how to employ the law of love in a violent world—turned many Christian pacifists such as Reinhold Niebuhr away from pacifism and toward “Christian realism” in the 1930s and 1940s. The Christian realist argument reflects Augustine’s call for this-worldly policies to thwart evil, even if such policies dirty the hands of those engaged in fighting for justice and order. See Eric Patterson, ed., The Christian Realists (Lanham, MD: University of America Press, 2003), especially chap. 1.
 Aquinas, Summa Theologica, Part II, II, Question 40.
 This continues Augustine’s quote from above in Aquinas’ Question 4. Summa Theologica, Part II, II, Question 40.
 Aquinas, Summa Theologica, Part II, II, Question 40.
A good summary of the Catholic position can be found here: https://www.ewtn.com/expert/answers/just_war.htm.
 The Schleitheim Confession, the classic statement of the Anabaptist tradition can be found at: http://www.anabaptists.org/history/the-schleitheim-confession.html. Because it is so poorly understood, readers should familiarize themselves with, in particular, the section “On the Sword”. It is noteworthy that classical Baptists have not accepted this Anabaptist position. In fact, in 1524 the five Baptist churches of London publicly dismissed the Anabaptist view.