On Aug. 9, 2025, I attended a Memorial Mass at Nagasaki’s Urakami Cathedral, which was destroyed by the atomic bomb of 1945 dropped only 500 meters away. At 11:02 a.m. – the same time the bomb nearly leveled the cathedral 80 years prior – both bells in the rebuilt cathedral’s twin towers rang for the first time, marking an event that killed most of the community in this historic center of Japanese Catholicism.
I was privileged to be there with a Notre Dame delegation, led by Rev. Robert A. Dowd, C.S.C, the university’s president, as part of a larger Catholic pilgrimage to commemorate the 80th anniversary of the atomic bombings. The pilgrimage was organized by the Partnership for a World Without Nuclear Weapons. It was a moving week of looking back in order to envision a different nuclear future. The visit underscored the imperative to reengage and update ethical frameworks to constrain nuclear weapons. The Catholic Church, which helped bring morality into the nuclear debate in the 1980s, can lead the way again.
During the commemorations, the common appeal of the hibakusha (atomic bomb survivors) and the political, civic, and religious leaders was the same: the atomic bombings were immoral and nuclear disarmament is the only way to ensure that “never again!” is not just an empty slogan. Today, the risk of nuclear use is greater than at any time since the Cuban Missile Crisis, and perhaps since Nagasaki. The post-Cold War progress on arms control and disarmament has given way to a new nuclear arms race.
During the Cold War, the religious and moral debate on nuclear weapons focused mostly on the ethics of use and deterrence, and the need for progress on arms control to address both. Since then, the moral debate has focused on the imperative of nuclear disarmament and the ethics of international order. Pope Francis rejected even the possession of nuclear weapons, and the Holy See was among the first states to ratify the Treaty on the Prohibition of Nuclear Weapons.
The Church will and should continue to insist that nuclear disarmament is a moral imperative and call for a new international order of cooperative security. But such appeals are insufficient to address the world’s current nuclear predicament. It is necessary to revisit and update old debates on the ethics of use and deterrence to address the new nuclear arms race.
In 1982, Pope John Paul II concluded that nuclear deterrence could be morally acceptable, as an interim ethic, if it was used as a step toward progressive disarmament. Pope Francis did not reject deterrence, in principle, but made a prudential moral judgment that existing nuclear deterrents are unacceptable because they are not being used as steps toward disarmament. An interim ethic is still needed to guide how to move from the immoral status quo to the long-term goal of nuclear disarmament.
In his address in Hiroshima on Aug. 5, Cardinal Robert McElroy of Washington, D.C., one of the leaders of the pilgrimage, provided an updated ethical framework for deterrence. Cardinal McElroy argued that the pope’s condemnation of possession means that “nuclear powers stand in a prima facie judgment of illegitimacy in their nuclear policies.” “That does not mean,” he noted, “that all elements of deterrence must be abandoned…. [but] demands that every decision by nuclear powers regarding modernization, targeting, deployment and alliance structures must be made within the context of whether specific decisions will advance materially the goal of limiting and ultimately eliminating the existence of nuclear weapons.”
Elsewhere, I have discussed the ethical dimensions of some of the specific policy decisions being considered by world leaders that need further evaluation. For example, is “modernization” of every leg of the triad, including land-based intercontinental ballistic missiles, really necessary to maintain a minimal deterrent whose sole purpose is to deter the use of nuclear weapons? Are the opportunity costs, human and financial, of each element of the modernization program justifiable in light of other existential threats, including climate change and pressing human needs?
In a statement released in Hiroshima, Fr. Dowd urged universities to “help bring about the moral about-face that is necessary if the world is to have any hope of escaping the nuclear predicament.” This requires us to reengage and update the ethics regarding nuclear use, deterrence, and arms control. While the long-term imperative will remain nuclear disarmament, we should imagine and elucidate the steps needed in the short- and medium-term to move toward that goal. The attention we continue to pay to Hiroshima and Nagasaki is not just about coming to terms with the past. It is also about the present and the future, and recommitting ourselves to the moral work of not repeating evil.
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Gerard F. Powers is the coordinator of the Catholic Peacebuilding Network, a faculty member at the University of Notre Dame’s Keough School of Global Affairs, and the director of Catholic Peacebuilding Studies at the Keough School’s Kroc Institute for International Peace Studies.
