Archbishop Wester at arms control conference: ‘There is no such thing as a just nuclear war’

Archbishop John Wester reiterated papal concerns about nuclear weapons and the use of artificial intelligence in weaponry during a keynote address.

Archbishop John Charles Wester urged continued international efforts toward nuclear disarmament in a speech Tuesday to a nonpartisan policy organization of arms control proponents.

“There is no such thing as a ‘just’ nuclear war,” Wester of Santa Fe, New Mexico, said in a live video address to those gathered for the annual meeting of the Arms Control Association on June 2 at the National Press Club in Washington, D.C.

The Arms Control Association, founded in 1971, encourages nonproliferation and disarmament efforts for nuclear, chemical, biological, and other weapons the organization says pose dangers to humanity. Wester has been one of the most outspoken bishops on this topic in recent years.

In his address, Wester quoted extensively from papal writings and speeches from recent popes, including Pope Leo XIV, who encouraged disarmament efforts from nuclear powers in his papal encyclical Magnifica Humanitas last month.

Leo called the 2021 Treaty on the Prohibition of Nuclear Weapons a step in the right direction but warned it’s “largely symbolic since the major nuclear powers have not agreed to it.” He also voiced concern for “a new arms race,” the development of miniaturized nuclear weapons, and the potential use of artificial intelligence (AI) to make combat decisions.

Wester quoted from the text in which Leo said it is erroneous to believe nuclear deterrence is an “indispensable prerequisite for security.” The archbishop noted “there had been progress” in the past with U.S. and Russian disarmament, but “whatever momentum we had is completely gone.”

“We’re now in a nuclear arms race that’s even more dangerous than the first,” Wester said in reference to efforts in the U.S., Russia, and China to modernize nuclear arsenals.

Wester said “we’ve got to take a sober look at what’s going on today” and take the “momentum of the past and harness it and move it forward” toward nuclear weapon abolition.

“We’ve done this in the past and we can do it again,” he said.

Wester also referenced Leo’s encyclical comments on fears that AI could be used in weapons of war, with the Holy Father urging leaders to “avoid a race to develop such arms.” The archbishop referenced research that found that AI models would choose to use nuclear weapons in 95% of the researchers’ simulated crisis situations.

The possibility that AI could hypothetically choose to “wipe out human civilization overnight is rather scary,” the archbishop said, echoing the Holy Father’s warnings.

In addition to citing Leo, Wester also cited Leoʼs predecessor Pope Francis, who also gave strong warnings against nuclear weapons, going so far as to say “the use of nuclear weapons, as well as their mere possession, is immoral.” Wester called this “a huge, huge statement” that goes further than other popes.

“The pope has said it’s immoral,” he said, and added that his question to Catholics who do not focus on the issue is: “What are you going to do about that?”

The archbishop penned a 51-page pastoral letter on nuclear weapons in 2022 and said most of the feedback he received from fellow bishops was favorable, but “there’s not a huge urgency” from most clergy because there are “so many other issues to deal with these days.”

“How do we get people to look at an issue that, for many, it just doesn’t seem that urgent?” he said.

Wester said he hopes for a stronger focus on nuclear disarmament from the U.S. bishops and intends to ask Leo to write an encyclical specifically about the threat.