Pope Leo XIV calls just war theory outdated in first encyclical

In short: Pope Leo XIV’s first encyclical says the Catholic “just war” framework is now outdated because it is too often used as a moral cover for going to war.

What happened

Pope Leo XIV released his first encyclical, Magnifica Humanitas. An encyclical is a formal teaching letter from the Pope to the Catholic Church.

In the document, Leo criticizes how “just war” thinking has worked in real life. He says it has “all too often been used to justify any kind of war” and calls the framework “now outdated,” according to reports quoting section 192. He still affirms a right to self-defense, but only “in the strictest sense.”

“Just war theory” is a long-standing Catholic approach linked to thinkers like Augustine and Aquinas. It sets tests for when war might be morally allowed, like having a just cause, being a last resort, using force in proportion to the threat, and protecting civilians.

Leo argues that modern warfare makes those tests hard to meet and easy to twist. He links this to artificial intelligence, which he says can speed up decisions and make enemies feel distant, like targets on a screen rather than people. He also warns that no algorithm (a step by step computer rule, like a recipe) can replace human moral responsibility in war.

Why it matters

Religious language is often used in public debates about military action. By saying “just war” talk can function like a fig leaf (a small cover used to hide something bigger), Leo is warning leaders and citizens to be skeptical when wars are presented as morally clean, especially as AI-driven weapons spread.

Source: NYTimes