Are soldiers to blame for wars?

Wars are started by princes and fought by soldiers but who is to blame?

For hundreds of years, tradition has maintained that princes are responsible for deciding when to go to war (jus ad bellum in Latin) while soldiers worry about how to fight the war (or jus in bello)¹. This tradition has been questioned in recent years and some argue that soldiers fighting an unjust war are themselves unjust, however moral their behaviour. I will show that this argument is not merely wrong but that it has undesirable consequences. I’ll begin by explaining the Just War Tradition.

According to the Just War Tradition², princes and soldiers each have a different set of conditions to be met for their war to be considered just.

The prince has six conditions.

1. Only the legitimate authority can start a war.

2. There must be a just cause.

3. There must be a right intention — you can’t use just cause as an excuse to achieve other goals.

4. The war must be proportionate — you can’t invade half of Europe just because someone killed your Archduke.

5. You must have the prospect of success.

6. The war must be the last resort.

Soldiers only have two conditions.

1. proportionality — you can’t go nuking their cities if a simple blockade would do the job.

2. non-combatant immunity — you can’t be killing civilians.

Those last two rules get a little complicated if, for example, civilians live next door to a dockyard or when they work in a bomb factory — but you get the gist.

The Just War Tradition was straightforward back when war involved marching your army into another country to fight their army but it’s a bit more complicated now that you can fire missiles from the comfort of your own home and when the other guys don’t even wear a uniform. But most countries still agree with its principles and its conditions have been adopted into international law.

---

Just War Tradition says the responsibility for starting a war lies entirely with the prince. If the prince follows the jus ad bellum rules, the war is just. If he does not, the war is unjust. Also, soldiers cannot be blamed for starting a war. As long as they fight fairly, they are blameless.

Jus in Bello

Philosopher Michael Walzer took this idea further and argued that soldiers on both sides are morally equivalent whatever the justice of their cause as long as they follow the jus in bello rules. According to Walzer, when a soldier puts on a uniform he has chosen to fight and given up his right to not be killed. Soldiers from both sides are entitled to kill their opponents without dishonour. Walzer called this the moral equality of soldiers.³

When soldiers fight freely […] their war is not a crime.
— Michael Walzer

To illustrate this idea, consider Erwin Rommel during the North African Campaign in World War Two. We all agree that the Nazis’ war was unjust but Rommel gets praise and admiration from soldiers on both sides anyway because he fought with honour. He even upheld his jus in bello obligations by refusing an order from Hitler to execute prisoners. The moral equality of soldiers says that Rommel is morally blameless despite fighting for an unjust cause.

This separation of responsibilities has been challenged in recent years and one philosopher, Jeff McMahan, claims that soldiers fighting an unjust war cannot be considered just whatever their behaviour on the battlefield.⁴ Conversely, the soldiers on the defending side should be considered innocent and to kill them would be as much a violation of the jus in bello conditions as killing civilians. McMahan uses a pair of analogies to explain why.

When they put on their uniform, soldiers in Walzer’s model are like two boxers who put on their gloves and step into the ring. They have both consented to punch and be punched. But McMahan claims that real wars are more like a mugger on the street who wants to steal your wallet. The victim has not consented to fight and should be considered morally innocent while everything the mugger does should be considered unjust because the mugging is unjust. In the same way, everything Rommel does in North Africa should be considered unjust because he is fighting in an unjust war. According to McMahan, this shows that the attacker and defender cannot be considered morally equivalent and the doctrine of the moral equality of soldiers should be rejected. But McMahan assumes what he sets out to prove.

Just War Tradition says that princes and soldiers have separate responsibilities but in the mugging example, the same person who decided to commit the crime (ad bellum), also carried out the crime (in bello). McMahan’s analogy combines the prince and soldier into a single person responsible for both and is not a useful comparison with war. McMahan may have a point though when he notes that the mugging victim is morally innocent.

The jus in bello conditions require that soldiers should not target innocent non-combatants. This is usually interpreted to refer to civilians but McMahan claims that soldiers on the defending side should also be considered innocent because, like the victim of a mugging, they have done no wrong and therefore to attack them is a violation of jus in bello. According to McMahan, this demonstrates that the moral equality of soldiers is mistaken because just defenders are entitled to kill their attackers while unjust attackers are violating jus in bello by killing innocent soldiers. However, McMahan’s argument assumes that the soldiers on both sides know who is fighting a just war and who is not. But this is rarely the case as I will show.

In the early 1980s, I joined the Royal Navy to defend against an unjust and illegal invasion of the Falkland Islands in the South Atlantic.⁵ While at sea, I had no access to the news and no reason to doubt my country’s jus ad bellum motivations. By McMahan’s standard, my actions as a sailor were just — though I had no way of knowing this while on patrol.

I was later drafted against my will to serve on a ballistic missile submarine with no right to refuse.⁶ Again, while at sea, I had no knowledge of the political situation, whether or not we were at war or who we were fighting. McMahan would argue that my ignorance was no excuse and that if we were to fire our missiles, I would be morally responsible if my country was fighting an unjust war. Worse, the target and therefore the justness of our cause — and therefore my moral responsibility — could change at any time. It would be strange to hold someone morally responsible for an action when he has no knowledge of his enemy, his cause or control over the result. One moment his action could be just and the next it could be unjust and he would have no way of knowing which. In more extreme cases such as the First World War, it may take decades of study to determine whether a war was just and, during this time, the soldiers are in moral darkness until the experts decide on the justice of their cause.

To address this enigma, McMahan proposes a distinction between moral responsibility and blame: a sailor who fires his missiles without knowing the justice of his cause is morally responsible but not blameworthy and a soldier who fights for an unjust cause can be excused. But this merely deepens the mystery. Now we must ask, ‘Should we convict a soldier who is morally responsible for their actions or not?’ If not, then what is the purpose of moral responsibility if it has no consequences?

---

McMahan also makes a consequential argument for holding soldiers morally responsible for fighting an unjust war. Using the example of America’s immoral war in Vietnam, McMahan argues that once they understood that the war was unjust, soldiers should have quit the army, refused to serve or run away to Canada. If soldiers were to refuse to fight in unjust wars, the princes would no longer have the resources to fight them. But this argument also runs into the problem that soldiers often don’t have the information to decide whether a war is unjust and governments are rarely forthcoming. Should soldiers run away from every war just in case? A pacifist might say yes but McMahan is not a pacifist.

One might also wonder whether holding a soldier morally responsible for fighting an unjust war — whatever their behaviour — might diminish their incentive to behave morally while fighting. Would Rommel have fought with honour if he was going to be condemned anyway? Or would he decide that he may as well be hung for a sheep as for a lamb? By upholding the moral equality of soldiers and the principles of the Just War Tradition, we encourage moral behaviour; tearing them down would result in wars that are all the more brutal.

---

McMahan begins with the idea that soldiers fighting for a just cause are innocent and should not be killed while soldiers fighting for an unjust cause are morally unjust regardless of their behaviour in battle. McMahan’s argument leads to confusion over whether soldiers are morally responsible. Traditional War Theory’s distinction between jus ad bellum and jus in bello provides clarity to ordinary soldiers and the moral equality of soldiers provides a reason for soldiers to fight with honour whether or not their cause is just. When soldiers adhere to the conditions of jus in bello their behaviour should not be considered unjust.

---

☕️ Buy me a coffee? ☕️
It won’t make me rich but it’ll make me happy.
(I promise I won’t spend it on beer!)

1. Traditional War Theory uses the Latin terms jus ad bellum and jus in bello in a callback to its mediaeval origins.

2. Stanford Encyclopedia of Philosophy. ‘War’.

3. Walzer, M. ‘Just and Unjust Wars: A Moral Argument with Historical Illustrations’.

4. McMahan, J. ‘On the moral equality of combatants’.

5. Ragged Clown. ‘A life in the Falklands’.

6. Ragged Clown. ‘Run Silent. Run Deep.’