A profusion of international norms influences state behaviour. Ambiguities and tensions in the normative framework can give rise to contestation. While research on norm contestation has focused on open debates about norms, we identify a second type of norm contestation where norms are contested through particular forms of implementation. We therefore distinguish between contestation through words and actions, that is, discursive and behavioural contestation. Discursive contestation involves debates about the meaning and/or (relative) importance of norms. Behavioural contestation, by contrast, eschews such debates. Instead, different norm understandings become apparent in the different ways in which actors shape the implementation of norms. Despite being a potentially powerful mechanism of challenging and changing norms, behavioural contestation has fallen outside the purview of the literature in part because it frequently remains below the radar. The two forms of contestation overlap when the practices of behavioural contestation are brought to the attention of and discussed by the international community. Thus, discursive and behavioural contestation are not mutually exclusive but can happen at the same time, sequentially or independently of each other. This introduction to a special section of the May 2019 issue of International Affairs, on ‘The dynamics of dissent’, develops the concept of behavioural contestation and outlines triggers and effects of this hitherto under-researched expression of dissent.
