By Andrea Tornielli, Vatican News.
Faced with the destructive power of modern weapons, it is very difficult to speak, as was done in past centuries, of the possibility of a ‘just war.’ As early as 1963, Pope John XXIII, in ‘Pacem in Terris,’ wrote that in the atomic age it becomes almost impossible to think that war can be considered an instrument of justice. In this same spirit stands Pope Leo XIV, who is making peace one of the central themes of his pontificate.
As people return to speaking about a “just war,” it is worth recalling the teaching on peace of the Popes who have succeeded one another on the Chair of Peter over the past hundred years. This teaching has gradually been enriched and deepened, to the point of recognizing how increasingly difficult it is to claim that a “just war” exists. Reflections based on the theology of past centuries and possible justifications for war fail to take into account that when theologians of earlier times wrote about these issues, wars were fought with swords and clubs—not with deadly weapons and machine-guided drones, a reality that raises moral questions of dramatic intensity. There has been a growing awareness that war is not a path to be followed.
From the 1917 letter to the belligerent nations by Pope Benedict XV, which described the First World War as an “useless slaughter,” to the efforts of Pope Pius XII to prevent the outbreak of the Second World War; from the words of Pope John XXIII in Pacem in Terris (1963), who wrote that “it is almost impossible to think that in the atomic era war could be used as an instrument of justice,” to the cry of Pope Paul VI at the United Nations,“No more war!”—and the often unheard appeals of Pope John Paul II to prevent disastrous conflicts in the Middle East: the Successors of Peter have consistently raised their voices with both prophetic insight and realism, though sadly they have often gone unheard.
The primary reference text is the Catechism of the Catholic Church, which acknowledges the right to legitimate self-defense but places “strict conditions” even on defensive war:
“the damage inflicted by the aggressor on the nation or community of nations must be lasting, grave, and certain; all other means of putting an end to it must have been shown to be impractical or ineffective; there must be serious prospects of success; the use of arms must not produce evils and disorders graver than the evil to be eliminated. The power of moderm means of destruction weighs very heavily in evaluating this condition.”