Reverse Spillover in European Defense and Migration Policies: The Case of Germany and Poland

Recent crises have underlined the urgent functional need for European cooperation in areas such as migration and common defense. Yet, progress is slow and nowhere near sufficient. This paper uses the concept of 'reverse spillover' to offer an explanation for these repeated failures. While the original neofunctionalist spillover concept argued that integration would follow the functional needs in related policy fields, 'reverse spillover' highlights the negative consequences of spillover effects between linked policy areas. For instance, conflicts in migration policies can hinder cooperation in security policies and vice versa. The paper uses the case study of German-Polish conflicts and cooperation in these areas to illustrate the concept of 'reverse spillover' and investigate its potential application to other fields of European integration.