By Phil Lawler ( bio - articles - email ) | May 26, 2026 Although I generally admired Pope Leo’s first encyclical, I was dismayed to read, in paragraph 192: Today, more than ever, without prejudice to the right to self-defense in the strictest sense, it is important to reaffirm that the “just war” theory, which has all too often been used to justify any kind of war, is now outdated. Pope Leo is not the first Pontiff to say that just-war theory is outdated. Pope Francis said the same thing. Even Pope Pius XII, who cannot be classified as a pacifist, said in his Christmas message of 1948: “The theory of war as an apt and proportionate means of solving international conflicts is now out of date.” But Pius XII, speaking in the aftermath of World War II, did not jettison just-war theory—even with the advent of The Bomb threatening new levels of mass destruction. No one short of Dr. Strangelove would think that nuclear war is “an apt and proportionate means” of resolving conflicts. A …