In Japan, visiting Hiroshima and Nagasaki, Pope Francis made three key points regarding nuclear weapons and nuclear energy. He declared the use of nuclear weapons immoral; the possession of nuclear weapons immoral; and endorsed the call of the Japanese bishops to eliminate the use of nuclear energy.

The three points were not a surprise, especially the first. But the implementation of the second and third raise issues that challenge the history of non-proliferation efforts.

The first point, that the use of nuclear weapons is immoral, is a long-standing application of Catholic just-war doctrine. Mass bombardment that does not discriminate between combatants and civilians has never met the criteria for conduct of a just war. The same would apply to certain techniques of conventional bombing, but nuclear weapons offend more obviously against the traditional just-war teaching.

The second point, that possessing nuclear weapons is itself immoral, was first made by the Holy Father two years ago. His argument follows two lines. The one that appears more prominent is that the cost of nuclear weapons cannot be justified when there is poverty to be ameliorated. The same arguments could also be made about expensive conventional weapons; indeed, arguments have been made that the presence of nuclear weapons in Europe during the Cold War was less costly than the conventional forces that would otherwise have been needed.

The second line of argument holds that if nuclear weapons are immoral to use, then the only reason to hold them is for deterrence, the concept known as “mutually assured destruction” (MAD). MAD is morally untenable, Pope Francis argues, as it depends upon having the power to visit destruction to the enemy that is itself immoral.

Interestingly, the only leader who actually controlled nuclear weapons to make that kind of argument about the “madness” of MAD was Ronald Reagan. He wanted the abolition of all nuclear weapons and proposed as such at Reykjavik in 1986. Soviet leader Mikhail Gorbachev refused him then, and the NATO alliance was horrified that Reagan would consider removing the “nuclear umbrella” that protected Europe against the threat of Soviet aggression.

After the end of the Cold War, it seemed that the time to tolerate grudgingly the madness of MAD had perhaps passed. In 2010, the Holy See under Benedict XVI argued that “the conditions that prevailed during the Cold War, which gave a basis for the Church’s limited toleration of nuclear deterrence, no longer apply.” The Cold War offered a certain stability in which MAD had a certain perverse logic. Does the same apply today?

Nuclear proliferation has been largely contained, with only North Korea recently acquiring nuclear weapons. The other current membership of the nuclear-weapons club — the United States, Russia, United Kingdom, France, China, India, Pakistan and (presumably) Israel — has been stable for many years.

Yet non-proliferation took a serious blow with the Russian invasion of Ukraine in 2014 and its annexation of Crimea. After the dissolution of the Soviet Union in 1991, Ukraine had the third-largest stockpile of nuclear weapons on its territory. It had physical control, even if Moscow retained operational control.
What should newly-independent Ukraine do with its nuclear weapons? It was persuaded to give them up, to have them removed from Ukraine or destroyed. The Bucharest Memorandum of 1994 was the instrument by which Ukraine, Belarus and Kazakhstan all gave up their Soviet-era nuclear weapons, the only time a nuclear power has gone non-nuclear.

In exchange, the other nuclear powers guaranteed their territorial integrity and promised non-aggression. The deal was this: You can give up your nuclear weapons because we promise that you won’t need them to defend yourselves. It was a diplomatic triumph, not of non-proliferation, but de-proliferation.

All that lies in tatters now, after Russian broke its solemn commitments in the Bucharest Memorandum and its aggression was meekly accepted by the other nuclear powers. The Holy See’s diplomacy was muted, too, on the Russian aggression, and, despite the priority given by Pope Francis to nuclear non-proliferation, the significance of the violation of the Bucharest Memorandum was not given any emphasis at all.

Thus the Russian annexation of Crimea and invasion of eastern Ukraine has put an end to any question of any state giving up its nuclear weapons in favor of international guarantees of security. Those guarantees have proven not to be of any value. The idea that any nuclear power would give up its arsenal is a dead letter now that the Bucharest Memorandum has utterly failed.

The third point the Holy Father made in Japan was that nuclear energy itself should be phased out. The argument was not that it was immoral, but bad for the environment in light of the Japanese nuclear disaster of 2011.

That’s a straightforward argument if you are concerned about nuclear accidents and waste. It’s more complicated if you think it imperative to reduce carbon emissions in order to fight climate change. Nuclear power does not produce carbon emissions as fossil fuels do. Thus it is not practically possible to be in favor of reducing carbon emissions and against nuclear energy in the short or medium term. It is this practical contradiction that the Holy See’s energy policy runs up against.

There is also a connection between nuclear energy and the non-proliferation of nuclear weapons. The Non-Proliferation Treaty (NPT) explicitly offers a trade: Don’t develop nuclear weapons and the nuclear powers will help you develop nuclear energy. Article IV is far-reaching:

“Nothing in this treaty shall be interpreted as affecting the inalienable right of all the parties to the treaty to develop research, production and use of nuclear energy for peaceful purposes without discrimination and in conformity with Articles I and II of this treaty.”

To abolish nuclear energy would mean setting aside the “inalienable right” of the NPT, which is the keystone of international law on nuclear weapons. Indeed, the nuclear deal negotiated by the Obama administration with Iran made the trade-off clear: Iran could develop nuclear energy but not nuclear weapons.

It is imaginable to have a world without nuclear weapons or nuclear energy, but it would require the replacement of the entire postwar diplomacy on nuclear proliferation and energy. And it would exacerbate the much-declared urgency of doing something about climate change.

The visit to Hiroshima and Nagasaki was symbolic and a powerful call for peace. But its effect on nuclear policy around the world will be limited.

Father Raymond J. de Souza is the editor in chief of Convivium magazine.