Who Is Powerful?

Previous studies have proposed competing theories to explain European intergovernmental conference (IGC) outcomes, but they fail to test these theories against one another. I examine the literature on IGC bargaining and derive several testable hypotheses. Using data on member state preferences at the IGC leading to the Treaty of Amsterdam, I first examine which member states favor integration and which are most skeptical of integration. I also determine which member states face the highest domestic ratification constraints. I then test the competing hypotheses found in the literature by calculating the bargaining strength of member states. I find that large member states have no more bargaining strength than the average member state; instead, domestic ratification constraints seem to confer power. States preferring less integration appear to outperform states desiring more integration. Supranational actors, as expected, have little power.