On August 6th and 9th, we remember the horrific atomic bombing of Hiroshima and Nagasaki in 1945. Every day we cringe knowing that, today, nine countries have nuclear weapons. The number should be zero.
Every pope since before the bombing of these two cities (excepting Pope John Paul, whose reign lasted only 33 days) has decried the existence of nuclear weapons. Now is an ideal time to remind ourselves of what the Church teaches.
Pope Pius XII (February 1943): "It is essential to ensure the nuclear technology is used only for peaceful purposes, 'because otherwise the consequence could be catastrophic, not only in itself but for the whole planet.'"
St. John XXIII (Pacem in Terris, 1963): "Nuclear weapons must be banned. A general agreement must be reached on a suitable disarmament program, with an effective system of mutual control."
Blessed Paul VI (June 6, 1968): “Nuclear weapons … are the most fearsome menace with which mankind is burdened. …We must encourage all countries, particularly those which have the chief responsibility for it, to continue and to develop these initiatives, with the final goal of completely eliminating the atomic arsenal.”
St. John Paul II (January 1, 2001): “The alarming increase of arms, together with the halting progress of commitment to nuclear non-proliferation, runs the risk of feeding and expanding a culture of competition and conflict, a culture involving not only States but also non-institutional entities, such as paramilitary groups and terrorist organizations.”
Pope Benedict XVI (January 1, 2010): "... I firmly hope that, during the Nuclear Non-Proliferation Treaty Review Conference to be held this May in New York, concrete decisions will be made towards progressive disarmament, with a view to freeing our planet from nuclear arms."
Pope Francis (UN Conference to Prohibit Nuclear Weapons, March 2017): “An ethics and a law based on the threat of mutual destruction – and possibly the destruction of all mankind – are contradictory to the very spirit of the United Nations. We must therefore commit ourselves to a world without nuclear weapons, by fully implementing the Non-Proliferation Treaty, both in letter and spirit.”