The United Nations wraps up its biggest diplomatic week of the year today with an issue that predates almost everyone in the building: nuclear disarmament. On Tuesday, September 29, the General Assembly holds a high-level meeting to mark the International Day for the Total Elimination of Nuclear Weapons, in the Trusteeship Council Chamber at UN headquarters in New York.

The meeting closes out the high-level week of the 81st General Assembly session, which brought presidents, prime ministers and ministers from the 193 UN member states together for days of speeches and closed-door talks. This year's session is presided over by Assembly President Khalilur Rahman of Bangladesh, under the theme "Restoring trust, managing transformation: A United Nations that delivers for all."

The arsenal keeps getting rebuilt

According to the UN's programme for the meeting, more than twelve thousand nuclear weapons still exist, and the countries that hold them have well-funded, long-term plans to modernize their arsenals. The doctrine of nuclear deterrence remains part of the security policies of possessor states and many of their allies. The UN notes growing frustration among member states at what it describes as the slow pace of nuclear disarmament.

The meeting's stated goal is to mobilize new international efforts toward a world without nuclear weapons, and to educate the public about what disarmament would deliver compared with what the arsenals cost. The message is a familiar one. Nuclear disarmament has been the UN's highest disarmament priority since the organization's earliest days, and the gap between the goal and the reality keeps widening.

Eighty years after the first resolution

The UN has been at this almost from the beginning. The General Assembly's first resolution, adopted in 1946, established an Atomic Energy Commission with a mandate to propose the elimination of atomic weapons and all other weapons adaptable to mass destruction. The commission was dissolved in 1952, and the weapons never went away.

Since then, the General Assembly has marked 26 September of each year as the International Day for the Total Elimination of Nuclear Weapons, a day the UN describes as a moment to reaffirm the goal of nuclear disarmament and press world leaders on the social and economic costs of the arsenals. Today's plenary is this year's commemoration. It will be webcast on UN Web TV, and the outcome of the meeting will be posted on the UN's page once it is issued.

A test of whether the UN can still deliver

Secretary-General Antonio Guterres has framed this year's high-level week as a test of whether countries still believe in working through the UN. He told leaders that the organization's founding conviction is that countries are safer and more human when they stand together. This is his last General Assembly in the job: his second term ends on 31 December, and the process of choosing his successor is already under way.

It is the latest in a string of UN interventions this month, from a call on the United States to halt third-country deportations to summits on climate action and the 25th anniversary of the anti-racism Durban Declaration. The nuclear disarmament meeting is the one that closes the week.

No one expects Tuesday's nuclear disarmament session to produce a binding treaty or a timetable. The nuclear-armed states are not attending to sign away their arsenals. But the UN describes the meeting as a way to keep nuclear disarmament on the agenda and to give the many countries without nuclear weapons a platform to say, in public, that nuclear disarmament belongs back on the agenda to say, on the record, that the status quo is not acceptable.

For a generation that grew up after the Cold War, the risk can feel abstract. It looks less abstract against the wars still being fought, including the grinding conflict in Ukraine, where escalation fears have kept the nuclear question in the headlines. Whether nuclear disarmament stays on the agenda once the speeches end is the question the meeting leaves open. More background on the day's programme is available in the UN's overview of the meeting, and UN News covered what is at stake this high-level week.