Petra Schleiter, Tobias Böhmelt, Lawrence Ezrow, Roni Lehrer
Social Democratic Party Exceptionalism and Transnational Policy Linkages

World politics, 2021: 73, issue 3, pp. 512–544
ISSN: 0043-8871 (print), 1086-3338 (online)

Political parties learn from foreign incumbents, that is, parties abroad that won office. But does the scope of this cross-national policy diffusion vary with the party family that generates those incumbents? The authors argue that party family conditions transnational policy learning when it makes information on the positions of sister parties more readily available and relevant. Both conditions apply to social democratic parties. Unlike other party families, social democrats have faced major competitive challenges since the 1970s and they exhibit exceptionally strong transnational organizations—factors, the authors contend, that uniquely facilitate cross-national policy learning from successful parties within the family. The authors analyze parties’ policy positions using spatial methods and find that social democratic parties are indeed exceptional because they emulate one another across borders more than do Christian democratic and conservative parties. These findings have important implications for our understanding of political representation and of social democratic parties’ election strategies over the past forty years.