Gas, Norms, and Statistics: The Jury is Still Out

Damir Kovačević, Afrimadona, and Martin Claar's (KAC) statistical adjudication between the potential role of norms versus strategic deterrence in preventing interstate chemical-weapons use is a welcome contribution (Vol. 26, Nos. 3–4, pp. 251–66). The authors conclude that a powerful non-use norm is the most convincing explanation for downtrending chemical warfare. However, closer examination reveals several analytical issues, including inaccurate presentation of data and alternative explanations, that may undermine their results. Further evidence is required to evaluate whether the effect identified by KAC is driven by normative prohibitions or other factors. Use of chemical weapons (CW) also continues with disturbing frequency in contexts not discussed by the authors, where norms against these activities may be more fragile.

KAC enter the debate over norms and deterrence noting a sharp reduction in interstate chemical warfare during the twentieth century....