Two Americans are facing off on the world stage. One leads the most powerful empire on the planet. The other leads the West’s oldest moral institution. The first thinks he is God. The second tells him that God, today, does not bless wars. This confrontation is not trivial. It is a symptom of a deep rift within Western civilization and, more broadly, within human society.
After Leo XIV declared: “Enough of the idolatry of the self and of money! Enough of the display of force! Enough of war!” And after he quoted Isaiah: God “does not listen to the prayers of those who wage war.” He added, in that unadorned evangelical style that is his hallmark, that “true strength is manifested in serving life.”
The next day, Trump responded that he is “not a big fan of Pope Leo,” who “plays games with a country that wants nuclear weapons” and who is “WEAK on crime, and disastrous on foreign policy.” Adding with an arrogance that leaves one speechless: “Leo wouldn’t be in the Vatican if I weren’t in the White House.” And sharing an AI-generated image in which he depicts himself as Christ the miracle-worker, surrounded by eagles and fighter jets, healing a sick person in the name of America.
In fact, by acting this way, and by subliminally reviving the justification of war in the name of God, Donald Trump embraces the thesis that the Church defended for a very long time, before changing its mind.
For the Church, like all proselytizing or conquering religions, long considered that certain wars could be just when they served its interests; before falling silent when wars became secular.
It was first Augustine of Hippo, in the 5th century, who held that war could be morally acceptable if it redressed an injustice, if it was decided by a legitimate authority, and if it was conducted with a righteous intention (thus in accordance with the interests of the Church); this was confirmed by the popes of the Crusades in the 11th century and systematized by Thomas Aquinas in the 13th century. A little later, the conquistadors invoked the civilizing mission of conversion that accompanied the conquest; and the English colonists in North America massacred the Indians in the name of divine Providence.
Then the Papacy ceased to proclaim the righteousness of wars, first by maintaining a tragic silence during the massacres of World War I and World War II.
Only then did the Church begin to timidly speak out against all wars. John XXIII first set limits in the encyclical *Pace in Terris*; the Vatican then protested when both Bush Sr. and Bush Jr. claimed their wars were just; and Pope Francis spoke out against the “militarization of minds.”
And today, it is Leo XIV who protests when Trump takes up the theme of just war for himself.
What is at stake between these two Americans is therefore not a personal feud. It is a clash of paradigms. On one side, a normative vision of the international order, which the Church embraced by aligning itself with the post-World War II world order (institutions and rules superior to states, inalienable rights, a moral responsibility that transcends the raison d’état): and on the other, a cynical view of the world (force legitimizes the actions of states when the cause is just, and when negotiations fail, using, if necessary, a religious cover to legitimize their struggle). And this is also what is at stake when governments and political movements use many other religions to justify their desires for conquest or power.
Trump’s diatribe against the Pope is therefore not a communication blunder. It is a deliberate political act. Trump scoffs at international law. He couldn’t care less about the Vatican, the UN, or the European Union. His legitimacy lies in himself and, incidentally, in the American popular vote, which elected him “by a landslide,” as he puts it. In this system of thought, the leader’s interests take precedence over any supranational norm. And anyone who dares to challenge this logic—even if they are the Pope—automatically becomes a political enemy. By attacking Leo XIV, Trump is in reality targeting all those (Europeans, Japanese, Africans, Indians, international organizations, civil societies) who would dare to protest against his wars in the name of a so-called universal morality. All those who would seek to defend the rule of law and supranational institutions.
If most so-called “just” wars throughout history have caused greater suffering than they claimed to remedy, if they were just only in the eyes of one side, we can consider just, in the name of values that have become universal, the resistance of the Native Americans against European colonizers, the struggle of peoples against the Nazis, the revolt of colonized peoples for their independence, the defense of Ukraine against the Russian invasion, and many others.
International morality, grounded in values that have become universal and free from any religious pretext, can therefore consider a war just when it is a response to an attack; when it is a preventive action against a vital threat; when it is the last resort to protect the innocent, to prevent a declared enemy from attacking or acquiring lethal weapons.
However, this requires that all avenues of negotiation have been explored, that the threat is real and immediate, and that the war is conducted within the framework of the law, limited in its means, and carried out with a keen awareness of its tragic nature.