The origins lie with ancient thinkers. The origins of just war can be traced back to Cicero, who defined "just" war as warfare based on respect for an alliance, defence against aggression, and with the aim of establishing a lasting peace. Saint Augustine extended and imposed this concept. In an empire that was becoming Christian and had to be defended, although war was still considered an evil in itself, it could be used as a means of avoiding an even greater evil. So there are bad wars and good battles. The just war is based on a triptych: defence of the homeland, its citizens and property. It is a war of defence, undertaken to punish the wicked, and a war to protect and restore individual rights that have been threatened or violated. In the thirteenth century, Saint Thomas Aquinas theorised: "For a war to be just, it must be declared by a competent public authority, the cause must be just, and the intention of those who wage it must be upright". Christianity therefore only accepted war as an evil to be reckoned with, seeking to control it in every possible way.
With the birth of modern states and the Westphalian order, just war did not disappear, but was integrated into the law of war (jus ad bellum), which more or less took up the major guidelines defined by the Church, and even into the Charter of the United Nations. The Vatican is also actively engaged in diplomacy, advocating - even in the darkest times - a form of dialogue between the parties. Since the Second Vatican Council, the popes have been advocating disarmament by calling on leaders to reject the risk of nuclear holocaust. Is there a new development with Pope Francis? In his encyclical Fratelli tutti (3 October 2020), he calls for a return to universal brotherhood and an open world (without walls, borders, excluded people or foreigners). Emphasising that war cannot be a solution, the Pope states that "[w]ar is not a solution. the risks [in war] will probably always be greater than the hypothetical utility attributed to it. Faced with this reality, it is very difficult today to defend the rational criteria, matured in other times, for talking about a possible "just war". Never again war "1.
However, this encyclical deserves to be reread in the light of the war in Ukraine and the way in which Francis and the Church have committed themselves to this dialogue: during the Urbi et orbi blessing for Easter 2022, he exhorted people not to get used to war: "... we must not become accustomed to war. May those who are responsible for the Nations hear the cry for peace from the people "2 and more recently, against a backdrop of escalation and nuclear threat, on 2 October this year, calling on the President of the Russian Federation to " to stop this spiral of violence and death", including "for the good of his people", and for the President of Ukraine to be "open to serious peace proposals "3.
To speak of a just war is also to support the construction of peace; and the military, on a daily basis, in our open and democratic societies, are builders of peace, preventing the unleashing of violence and guaranteeing, to the best of their ability, the protection of populations. Need we emphasise how, in providing support to Ukraine, in giving soldiers under attack the means to defend themselves and their bombed infrastructure, there is always this desire to serve and protect the weakest?
1 Pope Francis, Fratelli tutti, 3 October 2020, https://www.vatican.va/content/francesco/fr/encyclicals/documents/papa-francesco_20201003_enciclica-fratelli-tutti.pdf
2 https://www.france24.com/fr/europe/20220417-le-pape-fran%C3%A7ois-appelle-%C3%A0-entendre-le-cri-de-paix-en-cette-p%C3%A2ques-de-guerre 17 April 2022.
3 https://www.lavie.fr/actualite/geopolitique/lappel-exceptionnel-du-pape-francois-pour-la-paix-en-ukraine-84545.php 2 October 2022.
