Abstract
City networks (CNs) are often enthusiastically regarded as key actors in processes of Europeanization and multi-level governance (MLG) policy-making in Europe and beyond. However, systematic research on highly contentious issues like migration is still scarce. Building on an understanding of MLG as a specific mode or instance of policy-making, in this article I seek to understand why and how CNs engage in MLG-like policy-making on a typical issue of state sovereignty. I apply the causal process-tracing method to analyse the genesis and policy actions undertaken in the last two decades by two migration CNs in different multi-level political settings: the Eurocities Working Group on Migration and Integration (WGM&I) in the EU and Welcoming America (WA) in the US. The results show that, notwithstanding the differences in the institutional settings, in both contexts instances of MLG policy-making have taken place in the shadow of the will of the national governments, which remain fundamental gate-keepers even in the EU supranational polity, where the European Commission has been particularly active in supporting migration CNs' initiatives.