This phrase, invoked often by Dag Hammarskjöld, the UN’s second secretary-general, is as realistic a description today of what the organisation can and cannot do as it was in the mid-1950s. “THE UNITED NATIONS was not created in order to bring us to heaven, but in order to save us from hell. The next secretary-general, its tenth, will need to be equally realistic about the world as it is and the role the UN can play. That will mean doing less, better.
As head of the International Atomic Energy Agency, I have balanced harnessing the power of nuclear science to support health, energy and other sectors with ensuring that nuclear is safe, secure and used for peaceful purposes. In hotspots around the world, the IAEA is responding to new challenges and new opportunities. My negotiations with President Vladimir Putin and President Volodymyr Zelensky made possible the establishment of the agency’s continuous presence at the Zaporizhzhia nuclear power plant, on the front line of the war, and at the other nuclear power plants throughout Ukraine. Last month my safeguards team and I visited Deir ez-Zor, a site in Syria that the IAEA had judged very likely to have been a secret nuclear reactor. The new government has agreed to grant our inspectors access, and we have finally resolved the safeguards issues stemming from the country’s past nuclear activities. Meanwhile, we continue to engage with Iran and others to support an agreement to ensure that nuclear weapons will not be developed there.
The IAEA has helped developing countries fight cancer, forging partnerships with the private sector and now working with more than 100 countries to bring radiotherapy to millions of people without access. On the energy-security front, the agency has partnered with the World Bank to support the responsible use of nuclear power for development—the first concrete step after a change of policy at the bank, which has not financed a nuclear power project since 1959.
The next secretary-general will have to deal with a world of competing powers and conflict in which the UN and sometimes multilateralism itself have been sidelined. Understandings and agreements that once existed among major powers—imperfect, but real as they were—have fractured. I saw this in the case of Iran. The five permanent members of the UN Security Council used to broadly agree on a common approach to dealing with ongoing questions about the nature of its nuclear programme. Not anymore.

