Catholic Teaching On Just War In A Dangerous Moment

The story of Father George Zabelka, the military chaplain who blessed the Enola Gay crew before Hiroshima, and who spent the rest of his life wrestling publicly with it, is a story that I only recently came across.

Father George Zabelka was a Catholic chaplain with the U.S. Air Force and served as a priest for the airmen who dropped the atomic bombs on Hiroshima and Nagasaki. In August of 1945, he was called upon to give the crew of the Enola Gay, the aircraft that dropped the first atomic bomb on Hiroshima, a blessing for their safety. This was an action that he had routinely performed hundreds of times, if not thousands. In fact, priests are called upon to bestow blessings for a variety of reasons. Blessing people is one of the gifts we priests are privileged to perform.

Just days later, Father Zabelka counseled an airman who had flown a low-level reconnaissance flight over the city of Nagasaki shortly after the detonation of “Fat Man.” The man described how thousands of scorched, twisted bodies writhed on the ground in the final throes of death, while those still on their feet wandered aimlessly in shock – flesh seared, melted, and falling off. The crewman’s description raised a stifled cry from the depths of Zabelka’s soul: “My God, what have we done?”

Over the next 20 years, Father Zabelka gradually came to believe that he had been terribly wrong, that he had denied the very foundations of his faith by lending moral and religious support to the bombing of Hiroshima and Nagasaki.

The moral weight of war falls on human beings precisely because humans bear moral responsibility, and this is as it should be. Reading about a brother priest who wrestled with his conscience and eventually had the courage to speak out against the actions of his country, was a moment of prophetic grace and moral righteousness.

As a bishop of the Catholic Church, and the proud son of a World War II veteran who served as a gunner on an aircraft carrier in the Pacific theater, it is important for me to discern carefully whether today is an historical moment and a key time when I should speak out clearly as a representative of the Catholic Church. And while it is sometimes difficult to know whether one is in an historical moment as it unfolds, it certainly feels that way right now, especially given the confluence of what I take to be two events with dramatic and long-standing implications. And I feel a special responsibility to speak up clearly for the Church’s teaching and vision at this moment.

The first is the Iran military conflict. This last January, the best news reports suggested that Iranian security forces in that country recently killed tens of thousands of peaceful protesters in the largest revolt since the Islamic revolution. On Feb. 28, Israel and the United States attacked Iran with a series of airstrikes from planes, missiles and drones. Though Iran has been a really horrific bad actor in the Middle East for decades, sponsoring terrorism by proxy which has killed many people (including U.S. soldiers), was there a clear, imminent threat posed by Iran in February, particularly considering that last June the U.S. had already destroyed a great deal of Iran’s war-machine infrastructure? Debatable. Were they starting to rebuild their nuclear facilities that we bombed last June? Probably. Were they currently capable of firing nuclear weapons on American soil or on U.S. bases in the region? Probably not. Do we have to wait until an enemy is on the brink of attacking us before we can act? Certainly not.

In addition, the goals of the conflict—from the perspective of the United States—remain unclear and sometimes switch day-to-day, based on who is speaking to the media: we’ve heard “unconditional surrender,” “regime change,” and targeting of nuclear and ballistic missile programs. Like many situations in war, the conflict is dynamic and threatens to involve many other countries. Indeed, the U.S. has called on our allies to help us open the Strait of Hormuz—currently being blocked by threats from Iran to destroy ships that are passing through—not least because it is driving up oil prices and inflation across the globe.

The second situation is the legal/ethical conflict between Anthropic (developer of the popular “Claude” AI system) and the Department of War. The U.S. military has been using Claude in many of its operations, very likely the extraction of Venezuela’s head of state, but Anthropic has been worried about Claude being put to use for two purposes it considers unethical: (1) AI-directed autonomous weapons (which kill without human oversight) and (2) mass surveillance of U.S. Americans (especially by de-anonymizing data, such as re-identifying individuals in data that were intended to be anonymous). The Department of War tried to change the contract to force Anthropic to allow for this, and when the company refused, they tried to destroy the company by designating it a “supply chain risk,” the first such designation leveled at any U.S. company.

In thinking about how a Catholic moral vision would address these two topics, let’s do a little “Just War Theory 101,” especially by focusing on the teaching we find in the Catechism of the Catholic Church.

Our Church is not inherently pacifist and does not mandate the renunciation of all violence. The Catholic Church teaches one has a right to self-defense against an unjust aggressor, even to use lethal defense if necessary. This right to self-defense also applies to nations when faced with an unjust aggressor-nation, but the Church is adamantly skeptical of war. CCC 2307 says: “The fifth commandment forbids the intentional destruction of human life. Because of the evils and injustices that all war brings with it, we must do everything reasonably possible to avoid it.” Our current Holy Father, Pope Leo XIV has recently and repeatedly emphasized this teaching.

The Catholic Church has a long history of developing Just War Theory, going back to the writings of St. Augustine in the 4th century, and further developed by St. Thomas Aquinas in the 13th century. The framework for a just war requires that war be a last resort, declared by a proper authority, have a just cause, and be proportional. The Latin term for this is jus ad bellum, the justification or reason for waging war.

According to CCC 2309, the following conditions must be met in order for war to be just:

(1) The damage inflicted by the aggressor must be lasting, grave, and certain
(2) All other means of putting an end to it must have shown to be impractical or ineffective
(3) There must be serious prospects of success
(4) The use of arms must not produce evils and disorders graver than the evil to be eliminated (the principle of proportionality)

When taken seriously, these are very strict and imposing regulations—ones which, again, reflect a deep Catholic aversion to war. There remain serious moral questions about several aspects of the Iran conflict, especially when it comes to whether it was really the last resort (2) and whether we have serious prospects of success (3), and even whether we have a clear sense of what success looks like.

The second dimension of Catholic Just War Theory is sometimes called jus in bello—the law that governs the way in which warfare is conducted. Even if the conflict in Iran is considered just jus ad bellum—a question that is still very much debated by Catholic moral theologians—we still need to make sure the war itself uses just means. CCC 2312–2314 gives us two core requirements:

(1) Discrimination: Non-combatants and civilians must not be deliberately targeted.
(2) Proportionality: The harm inflicted must be proportionate to the legitimate military objective.

The Department of War is understandably secretive about much of the technology it is using to fight wars, but its reaction to Anthropic suggests that it at least wants to make space to use autonomous weapons, which kill without direct human decisions being made about whether an innocent person is being targeted and whether the force being used is proportionate with the military objective.

But the Church is clear that such weapons could not be used justly, even in a just war, and Anthropic is right to resist here. As Catholic moral theologian Charlie Camosy put it recently, deadly actions in war “require human beings to be the ones morally responsible—and to take moral responsibility—in order for actions in a war to be just.” Camosy was quoted in a story about a group of Catholic moral theologians who submitted an amicus brief in support of Anthropic’s moral position here. They wrote that use of AI-directed autonomous weapons, by definition, fails to meet the conditions for jus ad bello required for acts of war to be morally licit in Catholic thought. Human involvement is crucial, because judgements of proportionality and discrimination are prudential and require human judgement, not the mere pattern matching of AI. Autonomous weapons do not possess a moral conscience. They cite the Vatican, popes, and the United States Council of Catholic Bishops in support of their position against autonomous weapons.

It is good to see Catholic scholars and Church institutions stand up at this moment, as, again, it does seem like a pivot point in history. Will the U.S. once again get bogged down in a terrible war in the Middle East, one with an uncertain objective and non-violent options on the table? Will that war, and other wars hereafter, be fought with drone swarms and other autonomous weapons which kill without human moral oversight?

One could make the consequentialist, utilitarian argument that—without moving in these directions—bad things will happen. Iran will continue to sponsor terrorism around the world. China and other countries will use autonomous weapons and outpace us on the battlefield. But Catholics cannot accept such arguments. There are certain standards for which we stand, regardless of consequences. Period.

Father George Zabelka died in1992, but his message, in a speech given on the 40th anniversary of the Japan bombings, still rings true today: “War is now, always has been, and always will be bad, bad news. I was there. I saw real war. Those who have seen real war will bear me out. I assure you, it is not of Christ. It is not Christ’s way.”

As I have said recently, I stand in solidarity with Pope Leo and Archbishop Paul Coakley, president of the United States Conference of Catholic Bishops, in urging Catholics and all people of good will to pray for a peaceful solution to the conflict in Iran. More destruction will only lead to more innocent lives being killed in the crossfire. Please pray that those in leadership positions can find a way forward without more destruction and bloodshed.

Bishop James D. Conley presides over the Catholic Diocese of Lincoln, Nebraska.