The military actions by the United States against Iran have been a recent point of tension between the Papacy and President Donald Trump. This has furthered discussion between more evangelical Christians and mainline denomination Christians as what constitutes a “just” war.

churches generally hold to what is called Just War Doctrine. This doctrine as it is today can be traced back to Saint Augustine in 400 A.D, he wrote on the subject of war after the Sack of Rome in 410 A.D, which was well before any split of the church into different denominations. This means that this teaching was widely accepted up until modern times.

The doctrine was further developed by Saint Thomas Aquinas, and even if you or your denomination doesn’t hold Aquinas to sainthood, both his and Augustine’s work set the historical and modern precedent for the Just War Doctrine.

So what does Just War Doctrine teach? It first teaches that all war is not inherently a good thing, but that it can be justified if it meets a certain criteria. There are three main ideas that both Augustine and Aquinas proposed for a war to be just: First, that the war was commanded by a rightful authority, second that it was done for a just cause, and third that it was done with the right intention.

The first idea, that of legitimate authority, says that for a war to be just, it must be declared by a rightful authority, meaning a King, President, or ruler. Aquinas says in Summa Theologica that  “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, because he can seek for redress of his rights from the tribunal of his superior,” which is saying that as individuals there is no reason to fight, nor go to war if we can reconcile disagreements through a legal system.

The second idea, that for a war to be just it must have a just cause, states that a war should only be waged if there is a reason. Augustine helps to clarify what constitutes as a reason: “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.” His quote is saying that a just war would be fought in order to correct the wrongs of another nation that refuses to right its wrongs itself in order to restore justice.

The third idea is that of a right intention. Aquinas says this: “That they intend the advancement of good, or the avoidance of evil. Hence Augustine says ‘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.’ For it may happen that the war is declared by the legitimate authority, and for a just cause, and yet be rendered unlawful through a wicked intention.” Aquinas is saying that if the war is declared to genuinely help those who are suffering, then it is just, but if it is done for a motive such as wealth or power then it is unjust.

So Just War Doctrine states that in order for a war to be morally justified it must be: Declared by a rightful authority and not an individual grievance: That the cause must be just, such as a restoring of justice, or the avoidance of evil; and that the true intention of the war must be for the good of the people. 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,” which supports the above three reasons.

That has been the historic doctrine of Christianity for a large portion of the religion’s history. Today it is still adhered to by many Christian denominations, and even if not explicitly taught as is the case with many US protestant denominations, they would still likely adhere to it.

So it can be seen that Just War doctrine has been the historical precedent for the Christian view on war, but does scripture back this doctrine? Absolutely it does, but some would say, “Does the Bible speak against violence?” to which I would say absolutely it does, which is the point of the Just War doctrine, that it lays out that violence is a negative thing. However, sometimes wars will have to be fought. That doesn’t make the act of killing any less of a grievance to God, but it does help us to know how wars should be conducted to prevent greater evil, and that prevention of greater evil is a Biblical theme.

First, the scriptural evidence for a legitimate authority. This can be found in Romans 13:1-4 which says that:

“Let everyone be subject to the governing authorities, for there  is no authority except that which God has established. The authorities that exist have been established by God. Consequently, whoever rebels against the authority is rebelling against what God has instituted, and those who do so will bring judgment on themselves. For rulers hold no terror for those who do right, but for those who do wrong. Do you want to be free from fear of the one in authority? Then do what is right and you will be commended. For the one in authority is God’s servant for your good. But if you do wrong, be afraid, for rulers do not bear the sword for no reason. They are God’s servants, agents of wrath to bring punishment on the wrongdoer.”

This passage establishes the fact that rulers of nations have the authority to enact justice against evil. This of course does not mean that every ruler’s actions are done for a just cause, but these verses establish that they have the authority to do so.

Second, the scriptural evidence for a just cause can be found in a multitude of places, but I will use two examples. First, Psalms 82:3-4 which says to:
“Defend the weak and the fatherless;

    uphold the cause of the poor and the oppressed. Rescue the weak and the needy;  deliver them from the hand of the wicked”
Second Proverbs 24:11-12 which says:
“Rescue those being led away to death; hold back those staggering toward slaughter.  If you say, ‘But we knew nothing about this,’ does not he who weighs the heart perceive it?”

These verses show there is a moral obligation to defend the innocent and to prevent innocent death, and therefore, that war for a just cause can be morally justified.

The need for a right intention is shown in Proverbs 6:16 which says:
“There are six things the Lord hates,

    seven that are detestable to him: haughty eyes, a lying tongue. hands that shed innocent blood”
And shown again in Psalm 11:5:
“The Lord examines the righteous,the wicked, those who love violence, he hates with a passion.”

When this scriptural evidence is put together, it tells the tenets of the Just War Doctrine that the ruler of a nation, with a just cause to protect the innocent, can with a right intention go to war. As part of that the war must also be waged to limit the harm to the innocent, for Isaiah 1:15 says: “When you spread out your hands in prayer, I hide my eyes from you;
even when you offer many prayers, I am not listening. Your hands are full of blood!”

To address criticisms of the Just War doctrine, starting with pacifism: Some would claim that the Bible never permits any kind of violence, despite the verses above. A common claim to support this would be Matthew 5:38-39 which says “You have heard that it was said, ‘Eye for eye, and tooth for tooth.’ But I tell you, do not resist an evil person. If anyone slaps you on the right cheek, turn to them the other cheek also.” To which I respond first with a quote from Augustine: “It is one thing to kill in self-defense, which is sometimes necessary, and another to kill in hatred or revenge.”

 It is seen in Exodus 22:2-3 that should you protect yourself from a thief you are not found guilty if your intent is self defense, so the call in Matthew is not to allow yourself to be killed nor in a flaw of pacifism to allow others to be killed, but instead forbidding personal revenge. This interpretation is backed by Ecclesiastes 3:1, 3, 8 which says that:
“There is a time for everything,

    and a season for every activity under the heavens:  a time to kill and a time to heal,

    a time to tear down and a time to build,  a time to love and a time to hate,

    a time for war and a time for peace.”
This verse supports the fact that while yes, you should turn the other cheek, occasionally there is a time to fight back. In a further argument against pacifism, Proverbs 24:11-12 may be used again, for if you have seen someone about to be harmed and you do not act you may be held accountable.

Now some may also say that because a war could be just, therefore war may be a first option. This is also a falsehood, for it is told in Matthew 5:9 that “Blessed are the peace makers.” War is a last option and should always be the last option, and should never be chosen for a personal or unjust reason. Some may claim violence to help the innocent, yet all the while may kill the innocent in the process, their intention is not right and as is told they will be judged for the blood on their hands. Now it could then be asked, are the soldiers and those who defend themselves murderers who are condemned? I first answer with a quote from Aquinas: “Nothing prevents one act from having two effects, only one of which is intended, the other being incidental.” He answered that in response to a question of self defense, and it can best be explained in an example: Two soldiers from warring nations come across each other, and in combat, one kills the other. That soldier is not a murderer if his intention is self defense in the war rather than the set purpose of killing and if he should be there for a just cause. The soldiers intended action was self defense which according to Exodus 22:2-3 is justified to the Lord; the incidental action is that he killed another. Because his intention was just, he is not condemned despite the fact that the killing, because it happened, is still a grievance to the Lord.

It is therefore written that war is not a good thing, nor should it ever be the first option. Though as seen in this world conflict may be unavoidable, not for the sake of violence but for the protection of the innocent and for the prevention of injustice. However the questions must be asked, is it from a legitimate authority or is it a personal agenda, is the cause just or is it for the glory of war, is the intention right or is it born of a selfish desire? And as Dostoevsky wrote “Above all, do not lie to yourself. The man who lies to himself and listens to his own lie comes to a point that he cannot distinguish the truth within him.”