A "No Nukes" Patron Saint
Is there a patron saint against nuclear war? I know there is an Eastern Orthodox patron saint for this cause, but I wanted to know if there is also a Catholic patron saint.
I don't know of a Catholic saint who has been formally assigned this patronage, but you could pray to St. John XXIII for this intention. One of the best known and most widely praised papal encyclicals of modern times was John XXIII's Pacem in Terris ("Peace on Earth"), in which he called for an end to the nuclear arms race:
Justice, right reason, and the recognition of man's dignity cry out insistently for a cessation to the arms race. The stockpiles of armaments which have been built up in various countries must be reduced all around and simultaneously by the parties concerned. Nuclear weapons must be banned. A general agreement must be reached on a suitable disarmament program, with an effective system of mutual control. In the words of Pope Pius XII: "The calamity of a world war—with the economic and social ruin, and the moral excesses and dissolution that accompany it—must not on any account be permitted to engulf the human race for a third time" (112).