Pope Leon XIV signs the preface of "Disarmed and Disarming": disarmament as the grammar of peace

Context

We had followed the Rome Declaration of July 16, 2026, signed at the Capitol after the World Assembly of Nobel Laureates on artificial intelligence and nuclear war held in Castel Gandolfo from July 14 to 16. Five days later, the Libreria Editrice Vaticana made public the preface that Leo XIV had signed to a collective work on peace and disarmament. Five editions of Vatican News (French, English, German, Portuguese, Arabic) broadcast the papal thesis on the same day: it is not atomic weapons that bring peace, but disarmament.

The Facts

The pope signs the foreword to a collection published by the Libreria Editrice Vaticana under the Italian title « Disarmata e disarmante. La pace è un dono » (« Disarmed and Disarming. Peace is a Gift »), in an edition directed by Alessandro Banfi. The volume gathers the speeches of Leo XIV on peace since his election on May 8, 2025. The German edition of Vatican News reports on the book under the title « Frieden, unbewaffnet und entwaffnend ». Leo XIV reiterates a programmatic formula: « May God guide us on the paths of non-violence. » The coordinated dissemination on the same day in five languages (French, English, German, Portuguese, Arabic) gives the event an editorial weight superior to the ordinarily discreet genre of the papal foreword.

Doctrinal Analysis

The thesis fits into a continuous magisterial lineage. Pacem in terris (John XXIII, April 11, 1963) affirms that true peace cannot be based on the balance of armaments but on truth, justice, love, and freedom. Gaudium et spes (Vatican II, December 7, 1965, § 81) qualifies the arms race as a « extremely grave wound of humanity » that « harms the poor in an intolerable manner ». The Catechism of the Catholic Church, in its number 2314, takes up Gaudium et spes § 80: « Any act of war directed indiscriminately to the destruction of entire cities or extensive regions with their inhabitants is a crime against God and man himself, which must be condemned with firmness and without hesitation. » Leo XIV places himself in this wake.

Stakes for the Church and the Faithful

The preface is not isolated. It constitutes the third act, in one week, of a coherent doctrine: the Nobel Assembly in Castel Gandolfo, the Rome Declaration at the Capitol (with its clause excluding AI from nuclear command systems), and then this anthology. The pope methodically builds a doctrine of integral disarmament that embraces the atomic weapon and lethal autonomous systems.

Critical Reading and Blind Spots

We must distinguish the registers. The preface falls under the ordinary magisterium of the Sovereign Pontiff, not the extraordinary magisterium. Second blind spot: nuclear deterrence. John Paul II, in his message to the Second Special Session of the UN on disarmament (June 11, 1982), had judged deterrence « morally acceptable » under the conditions of the time, but only as a « step on the road to progressive disarmament ». Leo XIV does not reopen this frontal debate.

To Meditate and Act

The faithful are called to receive this word not as a pacifist petition, but as a firm doctrinal reminder: just war (CCC § 2309) remains exceptional, and the nuclear arms race is already condemned by the magisterium. Pray for peace, refuse the media trivialization of nuclear weapons, obtain and read the book.