This article puts forward a constructivist-interpretivist approach to interface conflicts that emphasises how international actors articulate and problematise norm collisions in discursive and social interactions. Our approach is decidedly agency-oriented and follows the Special Issue’s interest in how interface conflicts play out at the micro-level. The article advances several theoretical and methodological propositions on how to identify norm collisions and the conditions under which they become the subject of international debate. Our argument on norm collisions, understood as situations in which actors perceive two norms as incompatible with each other, is threefold. First, we claim that agency matters to the analysis of the emergence, dynamics, management, and effects of norm collisions in international politics. Second, we propose to differentiate between dormant (subjectively perceived) and open norm collisions (intersubjectively shared). Third, we contend that the transition from dormant to open – which we term activation – depends on the existence of certain scope conditions concerning norm quality as well as changes in power structures and actor constellations. Empirically, we study norm collisions in the area of international drug control, presenting the field as one that contains several cases of dormant and open norm collisions, including those that constitute interface conflicts. For our in-depth analysis we have chosen the international discourse on coca leaf chewing. With this case, we not only seek to demonstrate the usefulness of our constructivist-interpretivist approach but also aim to explain under which conditions dormant norm collisions evolve into open collisions and even into interface conflicts.

This article provides an analysis of the normative framework for Spanish cannabis clubs by contextualizing it within the growing body of comparative constitutional law that recognizes legal obstructions to personal drug consumption as intrusions of the right to privacy. Article 3(2) of the United Nations Convention Against Illicit Traffic in Narcotic Drugs and Psychotropic Substances, 1988 relieves State parties from the Article's obligation to criminalize drug possession and cultivation for ‘personal consumption’ when doing so would conflict with their constitution or basic concepts of their legal system. Spain relied on Article 3(2) in its decision not to criminalize conduct involving personal consumption. The Spanish judiciary has had to consider the legal implications of collective consumption and cultivation in the form of cannabis clubs. In addition to operating in a grey area of domestic law, Spain's cannabis clubs straddle the blurred boundary in international and European legal instruments between ‘personal consumption’ and ‘drug trafficking’. This article explores the theoretical and doctrinal implications of both Spanish law on cannabis clubs and comparative human rights law on drug use to outline the potential contours of a constitutionally protected zone of privacy pertaining to cannabis use in a social context.