Magnifica Humanitas on War

The diagnosis: the culture of power and how it operates

Chapter 5 opens with a structural claim. Paragraph 182: “Peace is not simply one issue among others, but a prerequisite for the universal common good and a test of the moral maturity of peoples.” The chapter's argument is set up from the first paragraph: war is not a regrettable contingency that the encyclical must address in passing. War is the criterion by which the moral seriousness of the entire document will be measured.

Paragraph 183 names the AI connection directly. “AI acts as an accelerating factor in these processes, particularly within a context where many technologies are intrinsically ambivalent. Consequently, what is created for defense can be rapidly repurposed for offense, and the fine line between protection and aggression becomes blurred.” The argument is that the AI capabilities developed under the framing of safety, productivity, or beneficence will be repurposed for military applications, often by the same actors who developed them under the original framing. The dual-use problem is not a side concern; it is structural.

Paragraph 188 introduces the central term. “A culture of power is taking hold, in which the availability of resources and the ability to dominate tend to dictate the agenda and criteria for decision-making. In this way, the common good of humanity is relegated to the background and the concrete tragedy of peoples at war is reduced to a secondary consideration in relation to strategic interests.”

The culture of power, in the encyclical's framing, operates through four mechanisms. They are presented in sequence but they function together.

The normalization of war (¶189-192). The chapter notes that after World War II, “peace was made the focus of the international order” (¶189), with national constitutions restricting the use of force to extreme and strictly limited circumstances. Paragraph 190 then names what has changed: “We are witnessing a real paradigm shift in public discourse and in decisions regarding rearmament, with a troubling revival of war as an instrument of international politics, while the very ethical principles that had previously limited its use are being eroded.” Paragraph 191 adds the loss of historical memory: as the first-hand accounts of the World Wars disappear, the lessons disappear with them. Paragraph 192 contains the sharpest line in this section: “the 'just war' theory, which has all too often been used to justify any kind of war, is now outdated.” This is not a refusal of the just war tradition's underlying concerns about proportionality, discrimination, and last resort. It is a claim that the theory, as deployed in contemporary public discourse, has failed to constrain the wars it was supposed to evaluate.

Force without limits (¶193-196). Paragraph 193 names the military-industrial complex as “a defining feature of the current political landscape,” with “the close link between economic interests, the military apparatus and political decisions” producing an “armed nation” in which war becomes “a natural extension of politics.” Paragraph 194 addresses nuclear arsenals specifically, noting the 2021 Treaty on the Prohibition of Nuclear Weapons but also the “widespread yet erroneous belief that nuclear deterrence is an indispensable prerequisite for security” that has contributed to “a new arms race” including miniaturized weapons that make tactical use seem more viable. Paragraph 196 extends the analysis to non-state actors: jihadist groups, private militias, and criminal networks that mark “the end of the State's monopoly on the use of force” and that often transform war into “a way of life for entire generations of young people and children.”

The crisis of multilateralism (¶201-203). Paragraph 201 names what was supposed to constrain the culture of power: “The institutions established to safeguard the concept of a common future for all peoples and a global common good appear to have been weakened.” The post-1989 expectation that economic globalization would generate “unity and peace” produced the opposite: “fundamentalist, identity-based and nationalistic reactions.” The result is “not a far cry from genuine multilateralism; instead, what has appeared is a disorderly and conflict-ridden multipolarism with a prevailing sense of mistrust.” Paragraph 202 names the consequence: “the force of international law is thus replaced by the claim that 'might makes right.'” Tribunals are bypassed. Conflict prevention is neglected. The achievements of humanitarian law are being treated, in the encyclical's phrase, as “naive relics of the past.”

A supposed political realism (¶204-209). The fourth mechanism is the rhetorical one. Paragraph 205 names it directly: “a false realism, based not only on the prevailing mentality of force, but on the cultural and anthropological belief that war is an inevitable part of human nature.” The argument is that the position presenting itself as hard-headed realism is in fact a particular ideological position that “sows in consciences and in society an attitude of resignation to the inevitability of war.” The encyclical rejects this framing without claiming naivety: “peace is neither a naive hope nor merely the absence of war; instead, it is always possible as the fruit of justice and charity.”

These four mechanisms work together. The normalization of war reduces the cost of choosing it. The military-industrial complex provides the economic incentive to develop the capacities for it. The crisis of multilateralism removes the institutional constraints against it. The false realism legitimizes the resignation that prevents any of this from being challenged. The chapter's argument is that no single mechanism can be addressed in isolation, because each reinforces the others.

The demand: paragraphs 197 through 200 on lethal autonomous weapons

The encyclical's prose changes register in this section. The diagnosis is analytical; the demand is categorical.

Paragraph 197 frames the question. “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.”

The framing matters. The argument is not that autonomous weapons are technically risky or operationally premature. The argument is that their existence violates a principle: the use of armed force as a last resort. Autonomous weapons make war easier and less governed by human judgment, which transforms what was supposed to be exceptional into what becomes routine. The technical capability changes the moral landscape.

Paragraph 198 contains the document's sharpest single claim:

“Sometimes there is talk of 'artificial moral agents,' as if machines were able to distinguish between right and wrong with greater consistency than a human being. Yet moral judgment cannot be reduced to calculation, for it involves conscience, personal responsibility and the recognition of the other as a person. Therefore, it is not permissible to entrust lethal or otherwise irreversible decisions to artificial systems. No algorithm can make war morally acceptable. AI does not remove the intrinsic inhumanity of conflict; indeed it can only bring about conflict more quickly and render it more impersonal, lowering the threshold for resorting to violence, transforming defense into threat prediction and thus reducing victims to data.”

Magnifica Humanitas, n. 198

Read this paragraph slowly. Four moves are happening.

First, the rejection of the “artificial moral agents” framing. The encyclical refuses the premise that machines can outperform humans morally. The reason is not technical; it is anthropological. Moral judgment is not calculation. The capacities involved — conscience, personal responsibility, recognition of the other as a person — are not the kinds of things machines have or can have. The framing that suggests otherwise is dismissed.

Second, the categorical prohibition. “It is not permissible to entrust lethal or otherwise irreversible decisions to artificial systems.” The word “permissible” matters. The encyclical is not saying this is unwise or dangerous or premature. It is saying it is forbidden. The magisterial register of the claim places it inside the small category of things Catholic teaching names as categorically impermissible, alongside other absolute prohibitions in the tradition. The extension is from lethal decisions to “otherwise irreversible” ones, which extends the prohibition beyond weapons strictly speaking to other AI applications with permanent consequences.

Third, the magisterial declaration. “No algorithm can make war morally acceptable.” This sentence is doing rhetorical work that the surrounding analysis is not. It is the sentence that will appear in headlines. It is the sentence Catholic bishops will quote from pulpits. It is the sentence diplomatic delegations will cite in arms control negotiations. The encyclical knows this. The placement of the line within paragraph 198, in the middle of a section that is otherwise analytical, is deliberate.

Fourth, the consequentialist supplement. The categorical claim is followed by the practical consequences: AI in warfare makes conflict faster, more impersonal, more thresholds-lowered, more victim-as-data. This is not the basis of the prohibition — the prohibition is categorical regardless — but it answers the predictable response that the encyclical's position is too rigid. The encyclical is saying: even on consequentialist grounds, the case for autonomous lethal weapons fails. The categorical and consequentialist arguments converge.

Paragraph 199 then specifies the criteria for ethical discernment. Three are named. Personal responsibility, which must be “identifiable and verifiable” through a chain that does not collapse into “the machine.” The moral timeframe for judgment, which speed and efficiency must not override. And the identification and protection of civilians, which target selection and the use of force must respect.

Paragraph 200 closes the section with three non-negotiable requirements that operationalize the framework. First, all war-system decisions must be retraceable so that accountability cannot be collapsed into the machine. Second, the decision to use lethal force cannot be delegated to opaque or automated processes but must remain under “effective, self-aware and responsible human control.” Third, an international framework must be established to curb the technological arms race and ensure robust protection of civilians and the infrastructure necessary for their survival.

The third requirement is significant. The encyclical is not merely calling on individual states to refrain from developing autonomous weapons. It is calling for an international framework, which means a treaty regime, which means the kind of multilateral institution the chapter has just described as in crisis. The demand is operationally specific, and it is demanding in proportion to the magnitude of what is at stake.

The alternative: the civilization of love

Chapter 5 does not stop at the diagnosis and the demand. It develops an alternative. The civilization of love is a phrase the encyclical borrows from Paul VI's 1970 Regina Caeli address and expands at length in paragraphs 186-187 and 210-228.

Paragraph 186 names what the phrase is meant to do. “The civilization of love is no naive utopia, but a demanding project, which consists in translating charity into structures of justice, giving institutional form to fraternity and regarding others — whether individuals or peoples — as allies necessary for building the common good.” The civilization of love is not the absence of conflict. It is a particular way of structuring institutions, relationships, and discourse that gives charity practical form.

Paragraph 187 connects this to the AI question. “The project for a civilization of love, therefore, must undertake the task of transforming this imposed interdependence into a willed and chosen solidarity.” The digital networks and AI capabilities that have created global interdependence are the conditions within which the civilization of love must take shape. The argument is that the technology has produced the connection; the moral task is to make that connection something other than a vehicle for domination.

Paragraphs 213-227 then develop five practical contributions that the civilization of love asks for.

The need to disarm words (¶214). “Let us disarm words and we will help to disarm the world.” This is the phrase Pope Leo XIV used in his first address to journalists after his election. Paragraph 214 develops it. “Words have enormous power, something we experience in our daily interactions; for example, spoken words can change our mood for better or for worse.” The argument is that public discourse shapes the conditions under which violence becomes thinkable. The disarmament of language is the precondition for the disarmament of weapons. This is the kind of contribution the encyclical can ask of every reader: examine the words you use, the prejudices in them, the explicit or implicit aggression they encode.

Building peace through justice (¶215). Paragraph 215 cites Augustine's commentary on Psalm 84:11: “Justice and peace have embraced.” The argument is that peace cannot be achieved as the absence of conflict alone, because absences have no internal coherence. Peace must be the fruit of justice, which means that the conditions producing conflict must be addressed, not just the conflicts themselves.

Adopting the perspective of victims (¶216-217). Paragraph 216 names what this requires: “When we witness the bombing of civilians, attacks on hospitals, schools or vital infrastructure, and violence that affects children, we are confronted with scandals that wound humanity itself. For this reason, we cannot limit ourselves to the level of abstract analysis.” The encyclical is asking its readers, including its policy and academic readers, to engage the specific human reality of war rather than the abstract categories. Paragraph 217 specifies the Church's particular role: to be “a place of living memory for victims,” making their voices an appeal for peace rather than a prelude to new conflicts.

Cultivating a healthy realism (¶218). Paragraph 218 distinguishes the realism the encyclical commends from both idealism and cynicism. Idealism “tends to choose facts selectively, distorting and renaming them.” Cynicism “confuses observation with resignation.” The healthy realism the encyclical commends “does not give up on changing the world; indeed, it starts by clearly identifying interests, fears, constraints and power dynamics, precisely in order to determine what can be achieved.” The position is hard-headed without being defeatist.

Reviving dialogue and multilateralism (¶219-227). The longest of the five contributions. Paragraph 221 names the political task: “a shift from the 'culture of power' to a genuine 'culture of negotiation,' in which dialogue and diplomacy become the standard means of resolving conflicts.” Paragraph 222 returns to Pope Leo XIV's own words at the start of his pontificate: “The peoples of our world desire peace, and to their leaders I appeal with all my heart: Let us meet, let us talk, let us negotiate! War is never inevitable.” Paragraph 226 names the United Nations as the central instrument and acknowledges that “the current weaknesses of the UN and the international political system reveal the need for profound reforms.”

The final paragraph of the chapter, paragraph 228, closes in prayer. “For each of us, peace primarily comes from God, God who loves us all, unconditionally. It is a gift given by Jesus to his disciples on the day of Easter.” Pope Leo XIV then quotes his own first words as pope on the day of his election: “Peace be with you! It is the peace of the risen Christ. A peace that is unarmed and disarming, humble and persevering.” The chapter ends where his pontificate began.

What this chapter means for different readers

The war chapter reaches different audiences in different ways. Three matter most for the chapter's reception.

For diplomatic and humanitarian audiences. The chapter's center of gravity is closer to these audiences' concerns than pre-release coverage anticipated. The lethal autonomous weapons demand is operationally specific in a way magisterial documents rarely achieve. The call for an international framework gives diplomatic actors a magisterial reference point for arms control negotiations. The crisis of multilateralism is named in language compatible with the analyses developing inside multilateral institutions themselves. Diplomatic readers will find more of the encyclical's center of gravity here than they expected.

For AI developers and AI policy audiences. The chapter completes the argument Chapter 3 began. AI's most consequential effects, in the encyclical's reading, are not in the consumer applications that dominate industry discussion but in the military domain. For developers working on systems that could be adapted to lethal autonomous use, the paragraph 198 prohibition is the relevant magisterial position. The fact that Anthropic co-founder Christopher Olah was the AI lab representative at the Vatican launch is not coincidental: Anthropic's prior public position against lethal autonomous weapons aligns with what the encyclical now declares categorically impermissible. For the audience-scoped read of what the document asks of developers, see Magnifica Humanitas for Developers.

For Catholic readers and Catholic institutions. The chapter is among the encyclical's most pastorally urgent sections. Catholic teaching on war has a long and complicated history. The chapter's claim that the just war theory “is now outdated” will be contested inside Catholic theological discussion for years. The civilization of love framework gives Catholic readers an alternative magisterial vocabulary that does not require the just war framework to be repaired. The five practical contributions in paragraphs 213-227 are addressed to every Catholic, not only to specialists.

Where this sits in the encyclical's structure

Chapter 5 is the second-longest substantive chapter, after Chapter 4 by a margin of four paragraphs. Its placement at the document's structural climax is deliberate. Chapter 3 introduces the AI ethics framework. Chapter 4 applies the framework to truth, work, and freedom. Chapter 5 takes the same framework into the place where its stakes are highest. The conclusion that follows (paragraphs 229-245) returns to spiritual and theological themes, but the substantive argument of the document closes with the war chapter.

This placement has implications for how the document should be read. A reading that focuses primarily on Chapter 3 misses the document's center of gravity. A reading that treats Chapter 5 as a separate appendix on a different topic misreads the document's structure. The AI ethics core and the war analysis are one argument, developed across the document, culminating in Chapter 5 because that is where the argument has been going all along.

The connective tissue between Chapters 3 and 5 is most visible in two passages. Paragraph 110, with its introduction of “disarming AI,” uses a vocabulary that paragraph 228 echoes when it closes with “a peace that is unarmed and disarming.” The same word is doing structural work across forty paragraphs of intervening text. Paragraph 183 then explicitly connects AI capabilities to the war chapter: AI “acts as an accelerating factor” in the dynamics Chapter 5 will develop. Readers who notice these connections see the document's structure more clearly than readers who do not.

The day-after analysis identified the weight of Chapter 5 as one of six moves pre-release coverage did not anticipate. For the broader pattern of unanticipated moves, see Magnifica Humanitas: What Was Surprising. For the cornerstone reference on the concept that connects this chapter to Chapter 3, see Disarming AI.