A Holy See-supported treaty banning the possession of nuclear weapons that is coming into force is buoying efforts by nations and nonprofit and church organizations working to abolish such armaments.

The Treaty on the Prohibition of Nuclear Weapons comes into force Jan. 22, three months after the 50th nation ratified the historic document.

Nuclear abolition supporters said the treaty puts the world's nine nuclear powers on notice that momentum to dismantle arsenals of the world's most destructive weapons is building.

"We have an opportunity to move in a different direction now. We have to convince the nuclear states to take this seriously, to take this as an opportunity to move to a new conversation in the nuclear age," said Marie Dennis, the Washington-based senior adviser to Pax Christi International's secretary general.

The treaty resulted from months of negotiations at the United Nations in 2017 led by non-nuclear countries. Dennis described the effort as an example of the Catholic social teaching principle of participation.

"People around the world who live in countries that are not part of the nuclear weapons countries or under the nuclear umbrella have realized more and more clearly that the whole world would be devastated by an exchange of nuclear weapons and the people of the world decided to do something about it," she explained.

The Holy See was a key participant in the process that led to drafting the treaty, providing encouragement and advice to negotiators, said Jesuit Father Drew Christiansen, a nuclear weapons expert who is professor of ethics and global development at Georgetown University.

He credited Pope Francis for the Vatican's work on the pact. "I think it's part of Francis' agenda to get this out there," he said. "As Francis begins to elaborate more about this teaching on arms and warfare, he'll speak out more on this issue."

The Holy See was the among the first to ratify the treaty, which was approved by 122 U.N. members. Netherlands was the only country to vote against it while Singapore abstained.

The nuclear nations and those under the U.S. nuclear umbrella opposed the measure and played little if any role in negotiations. In addition to the U.S., the countries possessing nuclear weapons are Russia, China, United Kingdom, France, Israel, India, Pakistan and North Korea.

Data from various sources, including the U.S. Department of State and the Stockholm International Peace Research Institute, show that the nine countries hold an estimated 13,440 nuclear weapons.

By Jan. 14, 51 nations had ratified the treaty.

Archbishop Paul R. Gallagher, the Vatican's foreign minister, told Catholic News Service Jan. 12 that the Holy See is encouraging nations to build trust and move toward abolition.

"We consider that an important part of our work," he said.

The British archbishop pointed to the statements and writings of popes dating to the papacy of St. John XXIII nearly 60 years ago who have implored the world to step back from the nuclear brink.

Pope Francis, in increasingly stronger terms throughout his papacy, has chastised the possession of nuclear weapons. "The threat of (the) use of (nuclear weapons), as well as their very possession, is to be firmly condemned," he said in an address to a 2017 Vatican disarmament symposium.

Acknowledging the difficulty the nuclear weapons nations face in disarming, Archbishop Gallagher said that nevertheless the church and its leaders will continue to provide "moral leadership" on the issue because of its effects on security and human development.

"The pandemic points out that we are indeed extremely vulnerable and (have) the opportunity not to depend on the possession of nuclear weapons, but (that there's) a whole array of factors," the archbishop said.

"We are very much trying to encourage people to have ... a more holistic approach to justice and development and care for creation, developing trust among people, education and health care and dialogue," he said. "These are factors in humanity's security at this time."

As Jan. 22 approached, the treaty received the support of the Scottish and English bishops, who called for the United Kingdom to "forsake" its nuclear arsenal and spend the money it would save on helping the poorest people of society.

They said in a Jan. 11 statement that the treaty offered an opportunity to build peace through dialogue rather than the threat of mutual destruction.

Beatrice Fihn, executive director of the International Campaign to Abolish Nuclear Weapons, the coalition that spearheaded work on the treaty and received the 2017 Nobel Peace Prize, commended the church's worldwide efforts to achieve nuclear disarmament.

"The Catholic Church, the Catholic peace groups, parishes, Pope Francis, they have done this for decades because they are convinced of the moral responsibility that nuclear weapons are illegal," Fihn told CNS Jan. 12. "Now we have been able to add this international treaty to confirm that what they have been doing is right."

Not surprisingly, the treaty has been opposed by the longest-standing nuclear powers. In October as the treaty neared the 50-nation threshold to trigger its entry into being enforced, the U.S. urged signatories to withdraw support.

In a letter, the U.S said the original five nuclear powers -- the U.S., Russia, China, France and Great Britain -- and America's NATO allies were unified in opposition to the potential repercussions of the treaty, The Associated Press reported.

"Although we recognize your sovereign right to ratify or accede to the Treaty on the Prohibition of Nuclear Weapons (TPNW), we believe that you have made a strategic error and should withdraw your instrument of ratification or accession," the letter said.

Fihn, however, expects the drive toward disarmament to continue because "most people don't like nuclear weapons."

Mary Yelenick, Pax Christi International's main representative at the U.N. in New York, agreed. She said as word about the treaty coming into force circulates globally more countries are expected to step up to enforce it, especially when it comes to weapons manufacturers.

"Now that this treaty is being publicized, it will name manufacturers and producers of nuclear weapons as international pariahs," she told CNS. "The narrative will be that they will be breaching an international agreement. People will talk about them in different ways. They won't be respected anymore."

Future steps, Yelenick added, could involve divestment by pension funds and other investors from nuclear weapons manufacturers, similar to the divestment movement in fossil fuels.

Father Christiansen acknowledged the ban treaty is not perfect and amendments to it must bolster the verification protocol. He said he expects the shortcomings to be addressed in future review conferences.

Still he wants the ban treaty to stay in place.

"It's important, I think, that people with expertise in arms control begin to give up their ideological resistance to the treaty and join the treaty to advocate for those kinds of new items that need to be added to the treat," he said.

Looming in the near future is expiration of the last remaining nuclear arms control treaty between the U.S. and Russia. New START, which caps the number of deployed strategic nuclear warheads and bombs by each country at 1,550 is set to expire Feb. 5.

Russian President Vladimir Putin has proposed a five-year extension of the pact, but has been rebuffed by President Donald Trump, who wants to bring China into talks. Chinese officials have refused. Arms control advocates are hopeful that President-elect Joe Biden will extend the treaty, opening the door to deeper cuts in the arsenals of both nations.

The treaty must be extended even for a shorter term, Archbishop Gallagher said, noting the Holy See "would certainly like that."