Pope Leo this week upended a long-standing Catholic teaching used since at least the fifth century to assess when war may be considered justified, a move experts say could have far-reaching implications for global powers.
The shift came in his first major document, issued Monday, which also called for global regulation of artificial intelligence and included what is seen as the church’s clearest apology yet for its historic support of transatlantic slavery.
In the encyclical, titled Magnifica Humanitas (Magnificent Humanity), Leo wrote: “The ‘just war’ theory, which has all too often been used to justify any kind of war, is now outdated.”
He added that humanity now has more effective tools for resolving conflict, including dialogue, diplomacy and forgiveness.
Chicago Cardinal Blase Cupich, a close ally of Leo who attended the Vatican presentation of the document Monday, told Reuters the pope is concerned about how the doctrine has been used by world leaders to justify war.
