--- - |2 Abstract Slovenia, a country that faced dramatic decline in economic growth and a relatively new European Union member, recently broke with the EU's consensus and announced its support for the proposed Convention on the Rights of Older Persons, a treaty widely expected to be very costly to implement. Using process tracing, counter‐factual analysis and a range of primary and secondary qualitative data sources, in this article I explore the influence of a transnational advocacy network (TAN) on this policy shift and the relevance of national actors and structures. I argue that while people often see TANs as motivated by principled and material imperatives, scholars have mainly explored how and why ostensibly moral transnational actors, such as international non‐governmental organizations, behave instrumentally. In this article, I invert this focus by discussing why a domestic TAN partner – a traditional interest group – mobilized around a human rights issue advanced by a TAN. In doing so, I draw on ideas from social movement studies and, more recently, from international relations to highlight the importance of domestic structures in constituting the identity and interests of individuals and organizations, and therefore their likelihood of supporting transnational norms. I seek to contribute to our understanding of the circumstances under which TANs succeed by unpacking the interactions between the national origin of domestic interest groups, and the crucial links between transnational and domestic groups that are responsible for TANs forming and thereby potentially exerting influence. - 'Global Networks, Volume 18, Issue 4, Page 625-643, October 2018. '