As an undergraduate, I studied Political Science at Houghton College with aspirations to become a lawyer in the Marine Corps. Midway through my time in college, I shifted my career path towards ministry but kept the major, adding a minor in Bible and Theology. My senior thesis combined my minor and major, political science and theology. I studied and wrote on just war theory from a Christian perspective, particularly focused on just war in a world with weapons of mass destruction (nuclear weapons). I’ve lost the paper, but retained much of the knowledge and interest, and the topic seems to be pressing itself into our consciences recently.

Unfortunately, we live in a sinful world, full of evils. In such a world, war is sometimes warranted, maybe even required. Reinhold Niebuhr wrote, “The sad duty of politics is to establish justice in a sinful world,” and “It is not possible to disavow war absolutely without disavowing the task of establishing justice.” That justice may require force, even violent force, is a sad reality, but a reality nonetheless. Augustine reflects, “People say a wise person will fight in wars that are just. But if someone remembers they are human, they will grieve that they must fight at all—even in a just war. Anyone who feels joy at even a just war has lost touch with their humanity.”

When necessitated, force must operate within legal and moral constraints. There are two key elements of a just war – jus ad bellum and jus in bello – the rightness of the war and the just execution of the war. A military action must meet both to be legal, just, and ethical.

Jus ad Bellum

St. Augustine and St. Aquinas contributed significantly to the development of a theology of just war, particularly jus ad bellum. Jus ad bellum (“right to war”) is concerned with the cause of war. For a war to be just, there must be:

1. A just cause. Just causes might be the protection of innocent lives (i.e., preventing a genocide) or self-defense. A war to claim the mineral rights to a land that you want is not a just war. A war fought because of a perceived slight to a king’s honor is not a just war. A war against a people because they are a different kind of Christian, or not a Christian, is not a just war. War to distract the nation from a scandal is not a just war. War for the sake of war is no a just war.
2. Lawful authority. War must be declared by those with the proper authority. A Texas rancher cannot declare war on Mexico over water rights to the Rio Grande River. Chevy cannot go to war with Japan because Toyota is stealing market share. Facebook can’t go to war with China because its site is blocked.
3. Just intent. The goal must be just: to establish justice and peace, to punish evil doers, to prevent the loss of innocent life, etc. Augustine wrote, “We do not seek peace in order to be at war, but we go to war that we may have peace.” Unjust goals would include vengeance or greed, or because ‘we need an enemy to build esprit de corps at home’.
4. Last Resort. War cannot be, must not be, the first resort. Only after other means have been exhausted can a nation justly go to war.
5. Reasonable Chance of Success. This criterion is often included in just war theory, but interpreted liberally. In my opinion, it is problematic.

A Christian perspective on war precludes out-of-hand wars of conquest, imperialism, or holy wars. So does international law. They do not meet the jus ad bellum requirements.

Preemptive strikes and preventive wars are much debated by just war theorists. A preemptive strike is justified when it is taken against an imminent threat. Attacking a force amassing on the border and preparing for an incursion, or shooting down a plane flying aggressively into one’s airspace, are examples of preemptive strikes and are usually deemed just. One power is justified in preempting an impending aggressive act by another power.

A preventive war is usually waged against a rising power, where delay is likely to lower the probability of victory or raise the cost of victory. Preventive wars look further into the future and rely on less certainty; not imminent aggression, but possible future aggression. By international law, preventive wars are not typically deemed legal. By ethical standards, they are unjust as they fail to meet the requirement of being a last resort.

Jus in bello

Jus in bello (“rightness in war”) dictates how wars are to be fought justly. A nation may have just cause to go to war, but that war must still be fought justly & morally. I’ll focus on three key principles: discrimination, humane treatment, and proportionality.

Discrimination in this context means that those fighting the war must distinguish between combatants and noncombatants. Paul Ramsey, a Protestant Just War theorist, argued for the principle of discrimination based on Christ’s commandment to love one’s neighbors. This love justifies warfare in defense of innocent neighbors, but also the way the war is prosecuted, striving to protect the enemy’s innocent neighbors. As weapons have evolved, discrimination is increasingly difficult. It was easier to steer the blade of the swords towards soldiers and away from maidens and children; it is much more challenging in times of bombs and missiles. Cardinal Ratzinger (later Pope Benedict XVI) wrote, “We must begin asking ourselves whether, as things stand, with new weapons that cause destruction that goes well beyond the groups involved in the fight, it is still licit to allow that a ‘just war’ might exist.” But, in principle, a distinction between soldier and civilian is still absolutely necessary.

This principle extends to civilian property, infrastructure, or necessities of life. Military personnel and equipment are just targets. Civilians and civilian infrastructure are not. It’s legal to target tanks, planes, troops, bases, depots, etc. It is illegal and unethical to target population centers, hospitals, schools, power grids, dams, etc. Additionally, it is illegal and unethical to target cultural artifacts – museums, religious sites, art. So, it is illegal and unethical to gun down an entire village because they aided enemy troops. Using anti-personnel land mines is illegal and unethical, too, because they are indiscriminate; they may kill or maim a soldier or a child playing soccer. Salting fields to kill crops and make the land unusable is unjust and unethical. Poisoning wells or destroying desalination plants that civilians need to live is unjust and unethical.

Some exceptions to the targeting of infrastructure are allowable when a resource, i.e., a power plant, serves a dual-use. If a power plant serves a missile battery and a school, it is a legitimate target, but only while it’s performing its military function. If the missile battery is eliminated, the power plant is no longer a legitimate target. Even when deemed legitimate, impact on civilian life, living, and livelihood should be carefully avoided.

In war, especially modern warfare, civilians are often injured even when legitimate targets are hit. Civilians are never permissible targets of war, and every effort must be taken to avoid harming them. Yet, the deaths of civilians do not necessarily mean the war or the action is unjustifiable. As German tanks roamed Europe during WW2, it was justified to attack them even if the likelihood was that civilians would be harmed by stray bullets, off-target bombs, or crashing planes. Civilians were not the target, but were unfortunate collateral damage, justified given that a greater evil would have been unleashed if they had not resisted.

Humane. Even enemy combatants must be engaged justly. The use of weapons intended to maximize suffering is deemed illegal and unethical (i.e., hollow point rounds, poison gas). Once a soldier is disarmed and captured, they become non-combatants and must be treated humanely. Attacking persons who are hors de combat (out of the fight) is grievously illegal and immoral. Refusing to take prisoners, i.e., offering “No Quarter”, is the tactic of pirates, not of soldiers. It is highly illegal and unethical. Once in custody, failure to treat prisoners humanely violates just war principles. Torture, use in propaganda, etc., are prohibited.

Lastly, proportionality dictates that the response rise to the level of offense but not significantly higher. In the schoolyard, I can’t justifiably punch a kid because he laughed at me falling off the merry-go-round. On the global front, Canada cannot bomb Caracas because Venezuela raised the price of coffee exports. A nation cannot respond to a conventional battle with strategic high-yield nuclear weapons. And no matter how grievous the offense, one nation cannot end an entire civilization, never to return again.

Jesus said of the poor, “You will always have the poor among you.” Sadly, I believe that is true of war also. As long as sinful men are leading every nation, and evil men are leading some nations, wars will happen. Even just wars are cause to lament. And plenty of wars do not meet the criteria of being just. In City of God, Augustine asks, “Why must an empire be unquiet in order to be great? Consider the human body. Is it not enough to have moderate stature with good health?” Too many wars are fought to build an empire, to stroke egos, or for a thousand other sinful reasons.

This post may seemingly apply to few – I don’t live in a military town like Norfolk, VA or Fayetteville, NC. But in a way, it applies to us all. Our leaders represent us. Our leaders and our military should be held to high legal and ethical standards.