The last time delegates from around the world met to review progress toward disarmament under the Treaty on the Non-Proliferation of Nuclear Weapons in 2015, they came away with no consensus on how to move forward.

At the time, the United States, Canada, and the United Kingdom -- urged by Israel -- stymied the adoption of a carefully worded text that had been negotiated throughout the monthlong review conference.

This time around, as the 10th review conference on the treaty approaches, non-nuclear nations, the Holy See and nuclear disarmament advocates are pushing for a strong statement on steps to achieve reductions in nuclear arsenals.

The conference was set to open Jan. 4. However, the U.N. Office of Disarmament Affairs announced a third delay Dec. 28 because of another surge in the COVID-19 pandemic. A U.N. official has tentatively set Aug. 1-26 as the new period for the review conference.

The delay is not deterring disarmament advocates, who will continue to organize for a more substantive outcome when the review conference is held.

"We've sent letters to missions. We've sent letters to bishops and other people in the Catholic Church urging people to keep pressing," Mary Yelenick, Pax Christi International's main representative at the U.N., told Catholic News Service in mid-December before the postponement was announced.

Yelenick and her fellow advocates are seeking to overcome the influence that a small number of nuclear-armed nations holds over the process in the hope of seeing a definitive consensus document emerge. They said such a document must call for compliance with the 51-year-old treaty's requirement to "pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament."

Jesuit Father Drew Christiansen, professor of ethics and global development at Georgetown University, expressed concern for the treaty's future if no consensus is reached.

"It won't say the end of the treaty, but (it would be a) disaster for the treaty because the non-nuclear states have made it clear with their frustration with the lack of progress on disarmament on the part of the nuclear states," he said.

Illustrating the importance of the upcoming conference, the chairman of a U.S. Conference of Catholic Bishops' committee has called on U.S. Secretary of State Antony Blinken to pursue talks that would fulfill the treaty's intent.

"We are witnessing the U.S. and Russia increase defense budget spending to modernize and upgrade their massive nuclear stockpiles," Bishop David J. Malloy of Rockford, Illinois, who chairs the Committee on International Justice and Peace, wrote in a Sept. 24 letter to Blinken.

He conveyed uneasiness that both countries, which maintain the world's largest nuclear arsenals, are "developing emerging technologies such as offensive cyber and hypersonic weapons" that "make it increasingly difficult to comply with" the treaty.

"We hope the Tenth NPT Review Conference scheduled for January 2022 will advance" the treaty's disarmament commitment, the letter said.

Implicit in Bishop Malloy's plea is the nuclear threat confronting humanity. It echoes calls to world leaders by Pope Francis and a top Vatican official to end dependence on any weapon of mass destruction as a means to guarantee security.

In his 2020 encyclical "Fratelli Tutti, on Fraternity and Social Friendship," the pope explained that "rules by themselves will not suffice if we continue to think that the solution to current problems is deterrence through fear or the threat of nuclear, chemical or biological weapons."

Cardinal Pietro Parolin, Vatican secretary of state, echoed the pope in a video message Nov. 17 to the Italian Committee for a Civilization of Love and its "Nuclear for Peace" project.

He said the COVID-19 pandemic should teach people that security does not come from a country's possession of nuclear weapons, but from working together to promote the common good with greater access to health care, a reduction of poverty and care for the environment.

"The ultimate goal of the total elimination of nuclear weapons is both a challenge and a moral and humanitarian imperative," he said in reiterating the Catholic Church's decadeslong call for disarmament.

Even with such an appeal, the effort to urge the nuclear powers that are part of the treaty to comply with it will be far more difficult under rules guiding conference participation.

Originally scheduled for 2020, the review conference has been delayed three times by the pandemic, forcing planners to limit attendance at U.N. headquarters to official country delegations. In the past, nongovernmental organizations could attend in person.

Despite the limits, disarmament advocates said they will continue to pursue various diplomatic routes to get their message across, especially because the issues facing delegates are more crucial than ever as new nations strive to enter the nuclear weapons club.

Susi Snyder, nuclear disarmament program manager at PAX, the largest peace organization in Netherlands and a regular partner of Pax Christi International, said she has been in talks with non-nuclear nations who want to keep all conference negotiations transparent.

The nuclear powers "need to get pressure from others who are in the room," Snyder told CNS from her office in Utrecht, Netherlands. "The question is who's deciding the policy (on such weapons). Is it the countries deciding the policy or is it a few corporate interests deciding the policy?"

"We're unpacking who has a vested interest and then holding governments accountable," Snyder said, stressing that if nations begin to reduce spending on nuclear weapons they will be better positioned to respond to other pressing challenges to human life and dignity.

Snyder also questioned the lack of openness among officials planning the review conference. She said that because attendance is limited, Gustavo Zlauvinen, an Argentine diplomat serving as president-designate of the conference, has a duty to meet with civil society groups and share their concerns at the U.N. meetings.

The Office of Disarmament Affairs did not respond to requests for a response.

Prior to the initially scheduled conference, Yelenick and Snyder noted that outreach has long been underway among disarmament advocates worldwide urging divestment from nuclear weapons manufacturers.

"We're keeping the focus on what do the weapons do," Snyder explained, saying that the effort will continue after the conference ends. "It's a reaffirmation that a nuclear war can never be won and never be fought."

Although they cannot attend in person, the advocates are planning side events online and outside U.N. headquarters to spur people to action. They believe that any future movement toward disarmament must be led by average people joining prayer vigils and demonstrations and voicing their concerns to decision-makers.

Along those lines, one U.S. prelate has taken a step in the hope of motivating people to act.

Archbishop John C. Wester of Santa Fe, New Mexico, led a 20-minute prayer service Dec. 19 at the Shrine of Our Lady of Guadalupe there and unveiled a sign depicting Pope Francis and a quote the pope offered during a visit to Hiroshima, Japan, in November 2019: "The possession of nuclear arms is immoral."

The archbishop told the 100 people in attendance that the archdiocese "needs to be facilitating (and) encouraging an ongoing conversation" about nuclear disarmament. He encouraged people to consider "our role in the current nuclear danger the world is facing."

The Los Alamos National Laboratory, one of the country's leading nuclear technology research centers, is located within the archdiocese. The laboratory recently opened a small office in a building across the street from the shrine.

Archbishop Wester encouraged people to be instruments of peace and to "pray for God's intervention" to keep the conversation going on the danger posed by nuclear armaments.

"Now is the time to commit ourselves to build peace," he said, "and I ask you to add your voice to mine in this urgent conversation."