International law at the subnational level: How political actors navigate between legalities

The implementation of international law in federal states is an under-explored process. Subnational entities regularly enjoy a degree of sovereignty, which raises questions such as whether – and how – international law is effectively implemented at the subnational level. This paper aims to observe how such implementation takes place in practice in Switzerland with a focus on the roles of subnational political actors, such as members of cantonal governments and parliaments, subnational bureaucrats and civil society actors. We use two contrasted case studies: the cantonal implementation of the Council of Europe’s Istanbul Convention on preventing and combating violence against women and domestic violence, and the obligation to make cantonal laws on data protection compliant with the European Union (EU) Directive 2016/680, in accordance with the Schengen Association Agreement (SAA). Based on an analysis of the official documentation and more than 50 semi-structured interviews with national and subnational actors (members of parliaments and governments, bureaucrats and civil society actors), we highlight the processes through which international obligations are implemented and translated into norms, policies and practices at the subnational level, and the complex roles played by subnational actors in this process. Furthermore, this paper offers a comparative analysis of the case studies, arguing against a monolithic conception of international law with regard to implementation. Indeed, while both treaties are legally binding in Switzerland, we observe different implementation processes and various actors’ attitudes towards their obligations. The paper ends with a discussion on the factors behind such differences (fields of international law, international consequences of non-implementation, organisations at the origin of the treaty, political balance of power at the subnational level) and their implications.