The just war criteria can be grouped into two sets of criteria: Those that govern the decision to go to war (jus ad bellum) and those that govern the conduct of war (jus in bello). More recently, some, such as Michael Walzer ("Introduction,” Arguing About War) and Mark J. Allman and Tobias L. Winright (“When the Shooting Stops”) have argued for a third set of criteria, jus post bellum (justice after the war), that address the theory and practice of peacemaking, military occupation and political reconstruction. I only discuss the first two below since there is little consensus over whether the third set of criteria should be included, and, if so, what they should be. I will probably return to this third set of criteria in a later post, however.
Jus ad bellum
1. Legitimate Authority – This criterion asserts that only legitimate authorities may wage war. The Christian just war tradition has tended to understand legitimate authority rather broadly. It argues that authority over matters of life and death belongs to God, and God has shared this authority with the governing powers, which is why governing authorities may wage war. Examples of legitimate authorities include individuals who rule through “dynastic dissent” (e.g., kings, queens, etc.) and democratically elected officials. An exception to this general rule is that officials who have gained their authority through legitimate means but are “bad” rulers (e.g., tyrants), forfeit their claim to legitimacy. Examples of illegitimate authorities include wars waged by private citizens (e.g., militia groups), bandits and privateers and rebellion against one’s own sovereign. An exception to this rule is that rebellion is permitted when the sovereign has lost claim to his or her legitimacy because they are tyrants or they lie. Furthermore, only soldiers under oath and under control of a sovereign can fight. Similarly, mercenaries are not allowed to participate in war unless it is for a cause they know is just. Clergy, the religious, and penitents are excluded from fighting, except individuals who are members of military religious orders (it used to be that a man who killed another, even in a just war, was not allowed to become a priest).
2. Just Cause – This criterion holds that a war may be fought for only a just cause, that is a justifiable, defensible and morally necessary cause (given the alternatives). To be just the offense must be actual and verifiable, intentional and of substantial importance (i.e., it cannot be a trivial cause). Furthermore, an offense cannot be provoked; that is, a queen or president can’t goad someone into committing an offense so that they can then declare war. The offense may be an aggression necessitating defense, a threat demanding deterrence (e.g., WMD’s), or an injustice demanding reparation (e.g., the Holocaust). It can be committed against a third nation, against either an ally or innocent subjects on whose behalf a legitimate authority intervenes. Just war theorists often disagree about when intervention on behalf of an oppressed population is legitimate. Walzer believes that the presumption must be against intervention, but he admits that there are times when the evil being committed is so great (e.g., the Holocaust) that intervention is necessary.
3. Right Intention, Right Motivation – This criterion states that in order for a war to be just it must be fought with a right intention. The ultimate goal must be the restoration of a just peace. Wars can’t be fought for national honor or territorial, economic aggrandizement and so on. It also must be fought with the right motivation. There needs to be genuine concern for the victims of the offense as well as love for the enemy, which is why demonstrating mercy after victory is sometimes listed by some as a criterion. Examples of inadmissible motivation include hatred, revenge, cruelty, love of violence or material gain. In other words, a cause may be justified, but participation in it may still be sinful if the intention or motivation is wrong in any one of these ways.
4. Last Resort – The just-war tradition contends that war must be the last resort, only after everything else has been tried or considered. Of course, how one defines “everything else” is somewhat problematic and subject to much debate since there is almost always something else that can be tried. Generally, what theorists have in mind is that the government needs to make a good faith effort to avoid war through negotiation, mediation, arbitration, appeals to international tribunals, cooling off period(s), and formal declaration of war, preceded by a warning and followed by time for the “offending party” to sue for peace. If all of these are sincerely tried (and fail), then most just war theorists would say that a good faith effort has been made.
5. Probability of Success – Finally, in order for a war to be just, success must be probable. If the wrong can’t be righted by going to war, there is no point in going to war. Of course, it is not always that straightforward when it comes to estimating the probability of succeeding. Sometimes, wars that look easy to win turn out to be much more difficult than anticipated.
Jus in bello
1. Proportionality – Once war begins the punishment must be proportionate to the offense (an eye for an eye…). Thus, the means used must be indispensable and necessary. Any intended destruction inflicted on the enemy must serve the stated ends of the just cause. We cannot destroy an enemy battalion simply because we can or because we seek a postwar advantage in further weakening the enemy. In short, unnecessary combat must be avoided even in a just cause. Put simply, there should be no unnecessary death or wanton destruction. We can’t poison wells or rivers, plant land mines, and/or bomb or profane places of worship or sanctuary. Furthermore, the enemy must always be allowed to sue for peace. We can’t kill an enemy who has surrendered. Other considerations often included under this criterion are that cease-fire agreements must be respected, occupied populations should be governed justly, and we can’t improperly use truce flags, enemy uniforms, or distinctive badges of groups such as the Red Cross, in order to lull the enemy into an ambush.
2. Non-Combatant Immunity/Dignity of Life – This criterion argues that the means used in war must protect the innocent (non-combatants). Armies must not intentionally or directly kill non-combatants. During a just war, they have an obligation to distinguish combatants from non-combatants and seek to minimize noncombatant death. This criterion, of course, essentially rules out obliteration bombing or the dropping of atomic bombs. Noncombatants include all who are not considered a threat: (1) women (traditionally), children (traditionally), the elderly and the infirm, (2) clergy, the religious and foreigners, (3) unarmed individuals pursuing ordinary vocations, and (4) soldiers who are on leave or have become prisoners of war. Noncombatants include all of the above not just those who oppose their country’s participation in the war (e.g., German women and children who supported Germany during WW II would still be considered non-combatants who should be protected from the waging of war).
It is important to note that in order for a war to be just, all of the criteria must be met, a point that is often lost in debates over whether a particular war is just or unjust. Students of mine at Santa Clara often fell into this trap. Anxious to prove that a particular war was unjust, they would attempt to argue that it was unjust on all counts (i.e.., in terms of all seven of the criteria). This led them to sometimes make poor arguments concerning one criterion that took away from the force of their arguments concerning the other criteria.
The fight against terrorism raises its own issues, in particular to the notion of noncombatant immunity since terrorists tend not to make such a distinction and often hide in places that makes targeting them without incurring collateral damage impossible. I will need to take this issue up in a later post since it deserves an extended discussion.
Three books worth considering if you are interested in exploring this topic further are (1) John Howard Yoder’s, When War is Unjust (Yoder was a pacifist but held the just-war tradition in high regard and taught a class on it for ROTC students when he was at Notre Dame), (2) Darrel Cole’s, When God Says War is Right (a somewhat more conservative take on the just war tradition), Michael Walzer’s, Just and Just Wars (considered a classic by many).