State Development and Use of Chemical Weapons

The use of poisons in warfare has a long history. During the 20th century, many states pursued chemical weapons, developing dedicated stockpiles and doctrines for their use. This extended across a wide range of covert battlefield and strategic weapons systems and was accompanied by developments in defense. Chemical weapons were first deployed on an industrial scale during the First World War. Over the following century, chemical weapons were developed and stockpiled on a significant scale and used by a number of states as part of colonial, counterinsurgency, terror, assassination, and ethnic cleansing campaigns. Throughout this period, both strategic and moral arguments have formed a key part of the broader social and political context of these weapons, as has the emergence of substate terrorist threats. However, to understand the evolution of this area of state policy and practice, there is also a need to take into account a broader range of historical forces—most notably, developments in science and technology, the changing character of warfare, and broader shifts in the international order. It is this broader environment that has continued to shape the evolving niches which chemical weapons have come to occupy as tools of warfare. It has also shaped the evolution of the global chemical weapons prohibition regime, the centerpiece of which is the Chemical Weapons Convention, which came into force in 1997. This treaty has overseen the destruction of all declared chemical weapons stockpiles and continues to verify state compliance with the prohibition. However, treaty implementation has been subject to several challenges. Among these are the use of chemical weapons in both the Syrian and Russia–Ukraine conflicts and the use of nerve agents as part of state-backed assassination attempts. Since at least the early 2000s, the focus of chemical weapons policy has increasingly been on preventing the resurgence of state programs and use, in addition to addressing concerns over substate proliferation. In this context, emphasis has been placed on the need to anticipate and understand the impact of advances in science and technology on nonproliferation system, to address the question of how to punish violators of the prohibition and prevent norm erosion, and to update and buttress international legal and regulatory frameworks in an increasingly fraught global political environment.