It’s the Middle Ages and you’re an ordained monk. You’ve just said Mass and are heading down the cloister to the library where you do your best work. You take a seat and consider picking up your quill. But you’ve got a lot to do. Volumes and volumes, to be honest. You sigh and dip your quill in the ink. You’re on your next volume of the Summa Theologicae.

Thomas Aquinas (c. 1225-1323) is best known for being incredibly thorough. So thorough was Thomas, a Dominican friar and priest, that he penned the five volume work more popularly known as the Summa Theologica, in which he discusses everything from the seven deadly sins to the purpose of marriage to how to conduct war. His work was so foundational to the Catholic Church that he earned the title “The Angelic Doctor” and scholars spend their lives studying the Summa.

One of Thomas’s projects that got carried through time and is still used in philosophical and theological discourse is just war theory. This theory predates Thomas, but you could say the friar perfected it. Just war theory posits that, in order for a nation to declare war, it must meet several qualifications or the war must not be waged. For Thomas, and for others before him, this gave an out for Christians to wage war, making some wars ethical and even necessary.

Today, we’re going to talk about just war theory, given its prominence in current events in the United States, and the way it pops up again and again as people debate whether or not to pick up the sword or the gun.

A Time to Wage War?

What exactly is just war theory? Just war theory is a philosophical blueprint for whether countries should take up arms against each other. Think about it like one of those flow charts that asks questions, and the answers you give lead to the next part of the flow chart. Thomas gives us three qualifications that must be met in order to get your war up and going. 

1. The Wager of the War

The first of these qualifications is that the person declaring the war must be a sovereign of a state. In modern times, this would just be the government. You can’t have randos from Florida waging a whole war with Italy because they feel like it. They have no authority to do so. This criteria is meant to prevent all and sundry going out to war against each other, and leave this decision up to a (theoretically) more intelligent governing body.

2. Just Cause

Secondly, if we want to get our war started, we need to have a just cause for the war. According to Thomas (and Augustine of Hippo before him), you need to have a reason for going to war. You can’t bring out the big guns just because. The state you’re waging war against has to have done something to you that deserves this, for instance. 

3. Intention

Finally, joined with cause is intention. Intention is the reason why you decided to wage the war in the first place. Did you do it because you wanted to help stop something bad from happening? Or did you do it because you wanted to get some goodies from another country? Did you do it to help advance good or to perpetrate evil?

These all sound simple until you put them into practice and start playing the games of politics and war with nations and civilians. The reality of war is more complex and visceral than the theoretical toyings of monks and saints.

A panel from the enormous Bayeux Tapestry, c. 1066-1082, courtesy of Wiki Commons

Issues with Just War

There are a few issues with this theory of warfare, some of which some of us have seen play out a number of times. Of course a government needs to be there to wage the war. What happens when the government is not a good government? What happens when the morality of the leaders in the government is more than questionable? This suggests that there are no stops in place for when an unjust government wages a war.

Secondly, just cause is deliciously vague. If there are perceived harms that are done to a nation, they are allowed to conduct a war. What if, for instance, the nation wages war because it needs someone to blame for something that happened to it?

We see just cause come up over and over. After the 9/11 attacks in 2001, philosophers and government officials scrambled to write reasons why the United States should lash out at Afghanistan and Iraq. I remember the debates about why the government should send young people out to fight against a shadowy “terror,” and die or return with terrible wounds and mental health conditions. 

During my time in high school, recruiters for every branch in the military were out in full force.

Looking back over 25 years, many in the United States would sigh and shake their heads about the justness of the wars waged in Iraq and Afghanistan. It didn’t take long for certain atrocities to be revealed to the public in the waging of this war, and of course, troops were jetted out of Afghanistan after 20 years of a fruitless and seemingly pointless war. 

The obvious question here is, what did specifically Iraq and Afghanistan do to the United States to merit an invasion? For what were the two nations being punished? 

Additionally, intention can be even more unclear than just cause. What if the nation suggests a pretty intention that makes everyone feel better but this is not the real intention behind the scenes? The memes going around of oil in the pan and the United States military showing up, while sarcastic, are not entirely inaccurate. Resources have been a reason the government decides to wage war, whether it is being truthful about it or not.

It’s important to note here that there are those who have added to Thomas’s just war theory, discussing what should happen within war, and what should happen after. These are the rules for conducting warfare, but they are open for much interpretation, which can be a good thing, but also a very bad thing.

Just War: Does Any Exist?

We have to ask ourselves if there is any war that can be considered just. It is essential to remember that when you are conducting a war, you are not simply throwing a bunch of Warhammer pieces on a table for a very long game. If that were the case, you’d just pack up your plastic dudes at the end of the day and shake hands with your buddies, probably more than slightly inebriated. You’d then sober up or order a rideshare and head home.

The truth of the matter is that the cost of war is, most importantly, human lives. And not just combatants. Even if warfare isn’t conducted with pillaging and rape (which, frankly, it almost always is), noncombatants are very, very frequently casualties, as collateral damage from a bomb, for instance. Or from drone strikes.

Additionally, warfare wreaks havoc on the environment. In order for the people of a country to recover from being bombed, they may have to employ small animals to discover landmines, or build up from nothing. Rotterdam in the Netherlands was bombed to hell during World War II. Its skyline lacks much of the charm of the rest of the country because the older buildings were simply demolished.

And this is not to mention what happens if those who waged the war start to occupy the country, if other nations get involved, or what happens to food supplies and water. The people of Ukraine, Palestine, or the Democratic Republic of the Congo might be able to answer some of these hypotheticals if you were to ask them.

Just war theory was created during a time when war was waged in somewhat neat lines on horseback and with swords and spears. Thomas, to his credit, could not possibly know the extent of the technological surge in the 20th century alone, that would make cities of people disappear with the drop of one bomb. 

Could we say that the technology has overridden the theory? When warfare doesn’t require face to face interactions, is it easier to destroy the humanity as well as everything else?

Christianity and the Permission to Wage War

A note here, as a currently nonpracticing Catholic who dabbles in Thomas Aquinas for academic purposes, and as a person who studied just war theory fairly extensively as an undergrad after the 9/11 attacks.

The Summa changed things for Christians, in many ways. We can talk about this another time. What the Summa gave us, though, was permission to wage war as a Christian. Thomas figured that rulers gonna rule, so what if they conscript Christian soldiers? By that time, of course, most of Europe was doing the Christianity thing. So, basically, Thomas decided to make sure that monarchs could get on with the war and not feel bad about it, and that people who were soldiers could do that, and not feel bad.

There is a heck of a lot of debate about whether early Christians were pacifists, but pacifism runs through various branches of Christianity, from the Quakers and Mennonites to the Baptists of the American Civil Rights movement. Just war theory is a theory that is embraced by the Catholic Church, currently, as well as secular places.

What Thomas (and Augustine, really) did was hand the sword to followers of a Son who was tortured to death. I will never claim that I am a theologian, but that doesn’t seem quite right. In fact, it seems like Christianity saw what everyone else was doing and just wanted to fit in, or sometimes do it bigger. It’s a cop out.

During a time when, in the States, the gas prices are surging, it seems more than a little ridiculous to wage yet another war. Especially when the people of Iran and Palestine have more to contend with than just high gas prices for their fancy vehicles.