The coevolution of cooperation and policy networks: Evidence from the Council of the European Union

The key characteristics of negotiations include patterns of cooperation among relevant actors, which we call cooperation networks, and patterns of (dis)agreement among the same actors, which we call policy networks. To what extent does the evolution of cooperation networks depend on previous policy networks, and to what extent does the evolution of policy networks depend on previous cooperation networks? This study examines the mutual dependency between cooperation and policy networks. We argue that the effect of policy networks on cooperation networks depends on the stability of the policy agenda. In policy arenas with fluctuating policy agendas, new and unpredictable policy networks emerge in the form of new alignments in actors’ policy preferences. These policy networks engender new cooperation networks in the form of future coordination and information sharing among actors who discover they hold similar policy preferences. By contrast, in arenas with stable policy agendas, established cooperation networks have strong effects on future policy networks. To test this argument, we deploy the stochastic actor-oriented model (SOAM), which enables us to examine the mutual dependencies between longitudinal observations of cooperation and policy networks. The empirical testing ground for our argument is the Council of the European Union. The data we examine include observations of the cooperation networks among member states and those same states’ policy preferences in a range of policy areas over a 20-year period. In line with our expectations, we find the strongest effects of policy networks on cooperation networks in policy arenas that are new and have the most dynamic agendas. The strongest effects of the cooperation networks on policy networks are in the longest established policy arenas with the most stable agendas.