The NPT, long the ‘cornerstone’ of efforts by governments in their pursuit of nuclear arms control, was for nearly 50 years the only open multilateral treaty that embodied the aspiration to rid the world of nuclear weapons. The states that drafted the NPT recognized that the challenge is not to reach consensus about a goal; they already shared the goal of nuclear disarmament. The challenge was, and remains, instead, how to achieve the goal in a world where practical arms control steps are constrained by strategic realities. They drafted the NPT with the realities in mind.

Today, however, we live in a world of two treaties concerned with nuclear disarmament. The second treaty— the TPNW— now gathers adherents. More governments are signing the TPNW as time goes on. Of equal consequence or more, the disarmament community, which once placed its faith in the NPT, has shifted its focus to the TPNW. If, as Matthew Costlow suggested, we inhabit an ‘echo chamber’ in which realists, having little enthusiasm for the NPT, remain silent, and in which disarmament activists lead the NPT discourse, then now we are approaching the point where even the echo is starting to fade. The activists now promote the TPNW and have less and less to say about the ‘cornerstone’ that preceded it.

Let us consider the TPNW in further detail, including the circumstances that led parties to draft it and the provisions that distinguish it from the NPT.

Origins of the TPNW

The pre-history of the TPNW covers a long course of humanitarian treaty-making and disarmament politics.

Going back as far as the 1925 Geneva Protocol which prohibits ‘asphyxiating, poisonous or other gasses’ and ‘bacteriological methods of warfare,’ states through the 20th century agreed prohibitions upon certain categories of weapon. Prohibitions of biological and chemical weapons, respectively under the 1972 Biological Weapons Convention (BWC) and 1993 Chemical Weapons Convention (CWC), are landmarks in this practice. More recent prohibitionary instruments include the 1997 Landmine Convention and the 2008 Convention on Cluster Munitions. These, and their forerunners, enliven the belief that far-reaching treaty measures might resolve the humanitarian challenges that warfare, particularly in its modern manifestation, entails. While the BWC and CWC enjoy wide subscription— 185 and 193 states parties, respectively— the Landmine Convention and Cluster Munitions Convention have attracted less support and more opposition.