The Treaty on the Prohibition of Nuclear Weapons (TPNW) was adopted in July 2017 with the consent of 122 countries at the United Nations (UN), and was finally ratified on October 24 2020 after Honduras became its 50th signatory. On January 22 2021, it will finally enter into force. 

The TPNW prohibits the possession and development of nuclear weapons, and mandates that all signatories assist victims of nuclear weapons testing and use. This marks the first time in history that the possession of nuclear weapons will be criminalized by international law, and this ratification has come at an important time. In addition to the immediate casualties of a nuclear detonation, even a limited nuclear war involving fewer than one hundred warheads would greatly disturb existing climate patterns and imperil the lives of two billion people by disrupting food production. Experts have increasingly warned of the accelerating likelihood of nuclear war, and in 2020 the Doomsday Clock has been set to one hundred seconds to midnight—the closest it has ever been.

If the threat from nuclear weapons is more apparent than ever, why are nuclear states like the U.S., U.K., China, and France opposed to the treaty—with the U.S. even urging signatory countries to withdraw support? 

These nuclear powers claim that the TPNW is divisive as it interferes with the Nuclear Non-Proliferation Treaty (NPT). They argue that the TPNW is not realistic in its approach, and it ignores the belief that nuclear deterrence is crucial for maintaining global peace. In this regard, it is ironic that these nuclear states, in spite of their insistence that the NPT is sufficient to maintain peace, have not entirely been abiding by its terms. Although the U.S., U.K. and Russia have decreased their stockpiles, their existing arsenals have been significantly modernized. Moreover, the U.S. is planning to spend more than one trillion U.S. dollars by 2040 to upgrade its nuclear capabilities, while China, India, and Pakistan have all increased their nuclear arsenals in recent decades.

Although the TPNW is a welcome move that brings us one step closer to a safer, more secure world, significant work remains. The treaty is not legally binding for non-signatories, some of which will continue opposing it. And with just 50 states ratifying the treaty, there are legitimate questions that can be raised about its efficacy on a large scale. For example, if a NATO member state decides to join the treaty, it will have to give up its stake in the nuclear umbrella, which is an assurance by the nuclear members of NATO to defend their non-nuclear peers. Thus, the TPNW does not provide states with an incentive to deviate from the status quo. 

A departure from the security of nuclear deterrence would require an alternative that provides more security in the long run. The treaty will have to deliver on its mandate of compliance—something which the NPT has failed to do. Moreover, the TPNW must leverage growing public discomfort with nuclear weapons, thereby changing their perception from tools used to keep peace and security to destructive weapons which pose a threat to human lives. The treaty must also promote a policy of naming, shaming, and boycotting to increase its outreach. Such policies have seen success in issues concerning human rights and climate change, and can be applied to countries, institutions, and officials involved in the development of nuclear programs. 

If the TPNW is to be truly successful, it must reach a general consensus with the U.S. Aside from being a leading nuclear power, the U.S. was the first country to create nuclear weapons and the only one, to date, to have used them in war. With the U.S. on board, the next step should be to seek greater global cooperation on mitigating risk from nuclear weapons. The TPNW came into effect because of the growing frustration associated with the NPT and its failure to achieve nuclear disarmament. Nuclear powers must be cognizant and respectful of this fact, as well as another fundamental truth: that nuclear weapons are catastrophic, and pose a threat to our survival.