The Catholic Church and the Concept of Just War

The Catholic Church's teaching on just war can be divided into two parts: 1) when it is permissible to go to war; and 2) how the war must be conducted. One may talk of a third part, securing a just peace in the aftermath of war, but I do not address that issue here.

The Church's teaching on war is particularly coherent and traces its roots back to St. Augustine of Hippo (AD 354-430). Before Augustine, Christian writers who addressed war and military ethics included Tertullian, Origen, and St. Ambrose. But Augustine is the first to articulate the foundational principles around the question of war. St. Thomas Aquinas (AD 1225-1274) later developed these principles into a structured framework in terms of moral theology.

This teaching can be summed up in the following sentence: War is to be avoided whenever possible, but when it must be fought, it must be fought morally. That is to say, war, in itself, is not something to be desired, but sometimes it is unavoidable, and when it is, there are limits to what is morally permissible.

Thus, it is clear that throughout most of its history, the Catholic Church has recognized the distinct moral realities of just and unjust war, and it is dishonest for those responsible for teaching the Catholic faith to conflate them both into simply "war" and to make moral statements about them as if they are the same thing.

Individuals and nations possess a natural right to defend themselves from unjust aggression. This should be obvious, even without the light of the Gospel. It is written on the human heart. It is natural law.

But Jesus gave us a new supernatural law, by which we are to love our enemies and do good to those who persecute us. We are to turn the other cheek. And if we are pressed into service for a mile, we are to go for two miles.

What does this new law mean?! If we want to follow Jesus, are we required to let unjust aggressors kill us without resistance? If we may resist, how? Only passively? With violence? Must we watch helplessly as an unjust aggressor rapes and kills our children, or threatens us or others with nuclear annihilation? How are we to live this new law without being simply led to the slaughter?

The answer is that the new supernatural law of Jesus Christ does not cancel the natural law. It perfects the natural law by imbuing it with the virtues. Particularly the virtues of prudence, justice, temperance, fortitude, moral clarity, and above all, with charity.

The Catholic Church's teaching about war is clear, and it doesn't require a doctorate in theology to be able to understand or apply. But it seems that most people have no understanding of it. And worse, judging from statements of bishops and priests whenever a new war breaks out, it seems most of them have conflated just and unjust war into simply "war." And war is bad. There rarely seems to be even a nod to the notion of a just war, and when there is, it is clear the principles of just war are not truly understood with any depth or nuance.

Given the grave nature of war, the failure of priests and bishops to accurately proclaim the fullness of the Church's teaching on war represents a staggering moral failure. There is no shortage of examples of clearly just wars they can use to teach. For example, no credible Christian theologian—true pacifists excepted— holds that the Allies in World War II should have let the Axis powers have their way, or that the only moral option the Allies had was to continue trying to negotiate with them. Negotiations had failed. There was no point in continuing them. As regrettable as it was, the only option left was war.

The Catholic Church, while continuing to plead for both sides to come to terms of peace, recognized this reality, and once the war started, even sent priests to accompany the troops, to minister to them, to bless them, to pray for their safety, and yes, to pray for their victory over evil as well.

WHEN IT IS PERMISSIBLE TO GO TO WAR

While the conditions for determining when it is permissible to go to war can be stated in various ways, they all include the following, which must all be simultaneously met:

1. It must be a just cause. There must be a true, grave, certain, and lasting danger or offense. This does not mean mathematically certain. It means that there must be sufficient certainty as would be required to take moral action in a grave matter.

2. It must be declared by a legitimate authority. Only duly constituted public authorities may declare war. In cases of revolution against an unjust government or tyrant, this requirement could broadly be interpreted to mean that there is some plausible alternative government, such as a government-in-exile.

3. There must be a right intention. The aim must be to secure a just peace, not revenge, conquest, or domination. The right intention can include the nation's own defense against an unjust aggressor, a credible threat of grave harm from an unjust aggressor, the defense of another nation, or the defense of a group of people being oppressed by a tyrannical government.

4. It must be a last resort. All peaceful alternatives that have a realistic chance of success must have been seriously tried and failed. This does not mean that negotiations must drag on indefinitely, but it does mean that they must have been conducted in sincerity and truth.  If the aggressor is clearly insincere in their negotiations, it is moral to break them off and proceed to military action.

5. Probability of success. There must be a reasonable chance of achieving the just objective. This does not need to be a mathematical certainty, or even a mathematical probability. There just needs to be a reasonable chance of success.

6. Proportionality (macro level). There must be proportionality between the expected and hoped for good, as compared to the anticipated harm and destruction. It is not permissible to go to war over a minor grievance.

HOW WAR MUST BE CONDUCTED

Even in a just war there are moral limits. The following criteria define how the war must be conducted.

1. Discrimination (noncombatant immunity). Direct attacks on civilians are always immoral. That doesn't mean that the person being attacked must be a formal member of the military. But they must be directly involved in the war effort. It also doesn't mean that there can be no civilian casualties. While civilian casualties can never be intended, they may be tolerated under the Principle of Double Effect.

2. Proportionality (tactical level). The force used must not exceed what is necessary to ensure legitimate military objectives are achieved. This does not mean that the other side must be given a "fighting chance". But to use an extreme example, it does mean that it is not permissible to use a nuclear weapon to bomb a bridge.

3. No intrinsically evil acts. Actions such as genocide or intentionally targeting civilians are always forbidden. This means that using civilians as shields for legitimate military targets, such as building a military command center inside a hospital, is not permitted.

CLARIFICATIONS

Note the following:

1. Given human frailty, it is almost inevitable that unjust means will be used in an otherwise just war. If this is kept to a minimum, this does not mean that the war overall has become unjust. Assuming the war is just, one may continue to wage it even if there have been instances of unjust means being used.

2. There is no prohibition against attacking civilian infrastructure, such as bridges or fuel depots, if necessary to attain a legitimate military objective. However, civilian infrastructure cannot be targeted as a means of terrorizing the civilian population or weakening their resolve.

3. There is no prohibition against being the first to declare war, especially when a grave threat is imminent, or negotiations are clearly being used as a stalling tactic by a belligerent nation to gain time to strengthen their forces. Thus, the term "imminent" can have a different interpretation, depending on the nature and gravity of the threat and the time required to prevent it from happening. For example, if a belligerent power is developing a nuclear weapon they clearly intend to use against another nation, "imminent" might be longer than it would be if the belligerent power were amassing troops on the border for a conventional invasion.

4. It is the responsibility of the civil authorities, not Church authorities, to determine if the conditions exist to justly go to war. It is the civil authorities who have the information necessary to make that determination, and the moral authority to do so. The Church's role is to educate civil authorities on the principles of just war. Not simply what the principles are, but how to apply them in concrete circumstances. To avoid any intrusion into the role of civil authorities, this education can be done using historical examples, rather than the circumstances of the present moment. This would be appropriate because civil authorities often have information that cannot be publicly shared, and using the present circumstances to teach would effectively usurp their authority.

5. Individual members of the military are morally obligated to follow orders unless they are clearly immoral or illegal. Orders are presumed to be both moral and legal in the absence of clear information to the contrary, and without such information it is neither a soldier's right nor responsibility to question the morality or legality of the orders they have received.

APPLICATION

It should not be hard for anyone to see that these principles make sense. They allow for grave, certain, and lasting injustices to be prevented or redressed. They follow the natural law. They serve as a framework for practicing the virtues of prudence, justice, temperance, fortitude, and charity, even in the context of war. They provide moral clarity.

It is essential that all civilian and military authorities with the responsibility to decide whether and how to wage war be adequately instructed in these principles, and to hold them to account when they fail to do so. They do not need to be Catholic to understand them, much less a moral theologian. These principles are accessible to anyone with an elementary school education.

There can be disagreement among good and faithful Catholics about whether these conditions are met in any given situation. Legitimate disagreement may arise from an invincible ignorance of the situation (e.g., classified information that cannot be made public), experience, or simply judgement. There is ambiguity in every situation, and we can't expect everyone to come to the same conclusion.

What is clear is that the Church's hierarchy is charged with proclaiming these principles to all people. Given the gravity of the matter, they have the responsibility to ensure that all students at every level of Catholic education can both articulate them and rightly apply them. Priests, bishops, and popes must proclaim them forcefully and clearly whenever war threatens or erupts.

But it is not the role of priests, bishops, and popes to declare this or that war to be just or unjust. To do so would be to usurp the role of civil authorities. Further, it would have the effect of causing unnecessary conflicts of conscience among ordinary citizens and members of the military.

American priests and bishops, along with the pope, have failed conspicuously in this task. In a world filled with war, they have neglected to adequately articulate, proclaim, and teach the principles of just war, even as they simultaneously speak as though they possess the prudential authority of civil authorities when conflicts begin. Rather than fulfill their solemn responsibility to form their flocks on a grave moral matter, they have settled for banal, tedious, and wishy-washy statements that blur the distinction between just and unjust war, placing both moral realities into a single category of "war," and treating them as if they are the same thing. It's easy to say "war is bad"; that is all they have done.

They have squandered their teaching authority, and the American people—instinctively recognizing the moral difference between just and unjust war—largely ignore them. In doing so, they have increased the likelihood of war.

Conflation leads to conflagration.