Treaty on the Prohibition of Nuclear Weapons (TPNW)

Slow progress in nuclear disarmament led to the negotiation of the Treaty on the Prohibition of Nuclear Weapons. The treaty entered into force on 22 January 2021 and prohibits the development, testing, production, transfer, possession, use, and threat of use of nuclear weapons. Switzerland has not yet acceded to the treaty, but is reviewing its position.

Nuclear disarmament is making slow progress and a world without nuclear weapons still seems a long way off. This is one of the reasons that led to the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2017, which aims to curtail the legitimacy of possessing nuclear weapons by declaring them illegal, thus creating room for more far-reaching disarmament steps.

This approach was controversial from the start and accordingly, all states in possession of nuclear weapons and the majority of their allies stayed away from the negotiations.

Content of the TPNW

The treaty prohibits among other things the development, testing, production, transfer, possession, use, and threat of use of nuclear weapons. It also prohibits supporting, encouraging or inducing third parties to support activities that are prohibited to the states parties. Furthermore, states parties may not allow nuclear weapons to be stationed on their territory. The TPNW also contains commitments on victim assistance, environmental remediation resulting from nuclear testing or the use of nuclear weapons, and international cooperation in these areas.

The Swiss position on the TPNW

Switzerland played an active part in the TPNW negotiations, issuing a statement on the outcome in an explanation of vote. In 2018, the Federal Council set up an interdepartmental working group to review the treaty and its implications. It concluded on balance that the reasons against accession outweighed the potential opportunities, considering among other things that the disarmament aspects of the TPNW were unclear.

In 2018 and 2019, the Federal Council decided to refrain from signing the TPNW for the time being. At the same time, however, it decided that Switzerland would take part in future intergovernmental conferences as an observer and would re-examine its position on the TPNW.

At the end of 2018, Parliament passed motion 17.4241: 'Sign and ratify the Treaty on the Prohibition of Nuclear Weapons'. Based on this decision by Parliament, the Federal Council will review the question of accession with the assistance of external experts. 

(de, fr, it)

Last update 22.03.2023

Start of page