Pope Francis is making a key shift in church doctrine on nuclear weapons, and some people are not going to like it.

The Catholic Church has long held that nuclear weapons must be eliminated from the face of the Earth.

Pope John XXIII, now a saint, wrote in 1963, “Nuclear weapons must be banned. A general agreement must be reached on a suitable disarmament program.” The church and the U.S. Conference of Catholic Bishops have worked actively in support of arms control and disarmament agreements, including the 2015 Iran nuclear agreement, the 2010 New START treaty between the United States and Russia and the 1996 nuclear test ban treaty.

When the pontiff speaks in Washington and New York this week, he will likely take the church position a step further. He may declare that any possession of nuclear weapons is immoral. No one should have them, at any time, for any reason.

Up to now, the church has abhorred the inhumanity of these weapons that indiscriminately target innocent civilians and would kill them in massive numbers. But—until now—it has recognized a need for states to have nuclear weapons to deter other countries from launching a nuclear attack on them.

No longer.

In a December message to a conference on the humanitarian impact of nuclear weapons, the pope wrote: “Nuclear deterrence and the threat of mutually assured destruction cannot be the basis for an ethics of fraternity and peaceful coexistence among peoples and states.”

Last week, the church was more direct. Reading a statement from the Holy See, the pope’s spokesperson said:

The world’s nuclear arsenals are much reduced since the height of the Cold War, but they remain excessive. Moreover, the dubious strategic rationales for maintaining and even strengthening these still bloated arsenals are morally problematic. Nuclear deterrence can hardly be the basis for peaceful coexistence among peoples and states in the 21st century, since it is unable to be broadly responsive and tailored to the security challenges of our times; furthermore, it risks being used in a way that would cause severe humanitarian consequences. Instead of being a step toward nuclear disarmament, nuclear deterrence has become an end in itself, and risks compromising the non-proliferation regime and undermining real progress toward a nuclear-free world.

In case there was any doubt about the direction the pope is taking, a December church policy paper stated,

Finally, it must be admitted that the very possession of nuclear weapons, even for purposes of deterrence, is morally problematic. While a consensus continues to grow that any possible use of such weapons is radically inconsistent with the demands of human dignity, in the past the church has nonetheless expressed a provisional acceptance of their possession for reasons of deterrence, under the condition that this be “a step on the way toward progressive disarmament.” This condition has not been fulfilled—far from it. In the absence of further progress toward complete disarmament, and without concrete steps toward a more secure and a more genuine peace, the nuclear weapon establishment has lost much of its legitimacy.

Expect the pope to be even more direct this week, as he speaks to a joint session of Congress and the United Nations General Assembly. This will not sit well with nuclear hawks in Congress and the administration. A trillion dollar build up of U.S. nuclear weapons is well underway. Some in Congress are calling for new weapons with new missions and administration leaders continue to insist on the importance of nuclear bombs.

Defending the U.S. nuclear weapons budget last week, Defense Secretary Ash Carter said the “nuclear deterrent is a must-have ... it’s the foundation, the bedrock, it needs to remain healthy and we all know we need to make additional investments, both in the Navy and, importantly, in the Air Force.”

The Pope, on the other hand, argues that “spending on nuclear weapons squanders the wealth of nations.” While Washington seems stuck in Cold War paradigms, the Vatican seems to have a more modern strategic analysis, pointing out that nuclear weapons do not address any of the real threats to nations and to humanity.

Obama personally is closer to the pope’s position. In 2009, he said, “I state clearly and with conviction America's commitment to seek the peace and security of a world without nuclear weapons.” But by allowing Pentagon programs to race ahead unconstrained as if the Cold War never ended, he has strayed from that goal.

As the pope would say, it is never too late to be saved. And Francis may be able to offer more than spiritual and strategic guidance. The American church through its bishops and parishes can speak directly to one-quarter of the American population that is Catholic and to over 130 Catholic House Members, about 25 Catholic Senators and America’s first-ever Catholic vice president.

With this support and just over a year left in office Obama still has time to set his ship on a more divine course.