Party policy diffusion in the European multilevel space: what it is, how it works, and why it matters

Almost since the end of World War II, transnational cooperation among political parties has been a common feature of European politics. This paper makes the case for studying transnational partisan cooperation in the European multilevel space, focusing in particular on the phenomenon of “party policy diffusion.” At the heart of the paper is a conceptual discussion of party policy diffusion in the EU. Specifically, we look at the (1) aims that lead parties to learn from or emulate parties in other countries; (2) the mechanisms through which this may work; and (3) the wider implications of this practice both for domestic and European politics. Drawing on this conceptual discussion, the paper then goes on to offer leads as to how the phenomenon of party policy diffusion can be studied in the European multilevel space. To this end, we briefly point to possible ways of testing hypotheses about party policy diffusion using spatially explicit modeling strategies such as spatial regression models and exponential random graph models for transnational party networks.