Why does this treaty matter if none of the countries with nuclear weapons have joined?


The Treaty on the Prohibition of Nuclear Weapons is a powerful normative tool to demonstrate that nuclear weapons are morally unacceptable. It strengthens the legal framework and legal stigma against nuclear weapons. The TPNW can put external pressure on nuclear-armed states to make further efforts on disarmament. 

The TPNW  reinforces other disarmament efforts by nuclear-armed states, such as the ratification of the Comprehensive Test Ban Treaty, further reductions of arsenals, and de-alerting nuclear weapons systems. The TPNW does not preclude or prevent bilateral or multilateral agreements to reduce numbers of warheads between nuclear-armed states.