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 by David M. Allison and Stephen Herzog in this response to the original article reveals several analytical issues, including inaccurate presentation of data and alternative explanations, that may undermine their results.