From: FirstThings.com by GEORGE WEIGEL

Pope Leo XIV’s spiritual lodestar is St. Augustine. In his first months in office, the Holy Father summoned the Church to pray, fast, and work for an end to the twenty-first century’s wars. That spiritual orientation and that summons invite us to consider what “peace” is possible in this world.
In his masterpiece, The City of God, the great Augustine defined “peace” as tranquillitas ordinis, the “tranquility of order.” This is not the peace of Isaiah 11:6, in which predators and prey co-exist (think of Edward Hicks’s sixty-two “Peaceable Kingdom” paintings). That, the bishop of Hippo knew, is the “peace” of the Kingdom of God, in the time beyond time when the redemption wrought by Christ will be completed and God will be “all in all” (1 Cor. 15:28). Nor is it the “peace” that Christians wish each other before approaching the Lord’s table, which is the “peace” of communion with Christ the Lord and, through him, with each other.
The peace of “order” is a more modest thing. The peace of order is built from just political and legal structures through which peoples can live in security and freedom. Conflicts continue, but conflicts are adjudicated and resolved by law and politics, not by mass violence. This is the “peace” that exists within properly functioning cities, states, and countries. Building a similar peace in world affairs is a more difficult task. But it is not impossible, at least in pieces: The example of the twenty-first-century peace that exists between France and Germany after two catastrophically destructive twentieth-century wars (and centuries of bloodletting before that) is worth considering.
What does this Augustinian approach to war and peace suggest about peace in Ukraine?
A historical vignette, possibly apocryphal, helps sharpen that reflection.
In the first volume of The Second World War, Winston Churchill quotes Marshal Ferdinand Foch, commander of the victorious Allied armies in World War I, on the Versailles Peace Treaty: “This is not peace. It is an armistice for twenty years.” Whether Foch actually said that is irrelevant. The point is that “peace” is not merely the cessation of hostilities, important as that can be as a step toward a just future. For unless a halt in the killing is followed by adequate measures to build the peace of order, there will be neither security nor freedom, only a temporary pause before the killing begins again.