https://www.vatican.va/content/leo-xiv/en/encyclicals/documents/20260515-magnifica-humanitas.html
[§192] ... Communication networks, fragmented information environments and algorithms that reward conflict can magnify polarization and resentment, increase propaganda and make shared discernment more difficult. Thus, war is not only fought, but also culturally conditioned through simplistic narratives, a friend-or-foe mentality, disinformation and fear. When historical memory fades and the ethical principles that protect civilians and the most vulnerable are weakened, it becomes easier to justify violence as necessary, inevitable or even “sanitized.” It is in this context that humanity is slipping into a violent culture of power, where peace no longer appears as a responsibility to be taken on, but as a fragile interval between conflicts. Today, more than ever, without prejudice to the right to self-defense in the strictest sense, it is important to reaffirm that the “just war” theory, which has all too often been used to justify any kind of war, is now outdated.182 Humanity possesses far more effective and capable tools for promoting human life and resolving conflicts, such as dialogue, diplomacy and forgiveness. The use of force, violence and weapons reflects a relational poverty that always has disastrous consequences for civilian populations.
[§195] ... Military force, weak diplomatic initiatives and the complexity of the interests at stake contribute to conflicts that tend to become protracted, with extremely high human and environmental costs. It is much easier to start a war than to stop it, and yet, discussion on conflict prevention remains tragically marginal.
[§196] The situation is further destabilized by the presence of new armed operatives, such as jihadist groups, private militias and criminal networks that mark the end of the State’s monopoly on the use of force. Often these groups intertwine vague ideological motivations with concrete economic interests, transforming war into a “way of life” for entire generations of young people and children. Here, the objective is no longer a definitive victory, but the perpetuation of conflict as a source of power and income.
[§197] The above-mentioned scenario is linked to the unceasing development of weapons systems, particularly those involving AI. The Holy See has recently observed that the growing ease with which autonomous weapons systems can be deployed makes war more “feasible” and less subject to human control. This violates the principle that armed force should be used only as a last resort in cases of legitimate self-defense. For this reason, the development and use of AI in warfare must be subject to the most rigorous ethical constraints, to guarantee respect for human dignity and the sanctity of life and to avoid a race to develop such arms.
182 Cf. Francis, Encyclical Letter Fratelli Tutti (3 October 2020), 258: AAS 112 (2020), 1061: “In recent decades, every single war has been ostensibly ‘justified.’” The Catechism of the Catholic Church speaks of the possibility of legitimate defense by means of military force, which involves demonstrating that certain ‘rigorous conditions of moral legitimacy’ have been met. Yet it is easy to fall into an overly broad interpretation of this potential right. In this way, some would also wrongly justify even ‘preventive’ attacks or acts of war that can hardly avoid entailing ‘evils and disorders graver than the evil to be eliminated.’”
