The question hinges on Article 11 of the treaty, part of which says a member cannot restrict trade with other members in a way that impedes the latter's development of chemicals for "industrial, agricultural, research, medical, pharmaceutical, or other peaceful purposes." Helms and his allies read this as being dangerously open-ended. But the very same sentence states that such restrictions are prohibited only if they are "incompatible with the obligations undertaken under the Convention." Obviously, restrictions that prevent another nation from developing chemical weapons would not be incompatible with those obligations. Other parts of the treaty make the case against the Helms interpretation overwhelming.