We present a uni ed model of the politics of the European Union (EU). We focus
on the effects of the EU’s changing treaty base—from the founding Rome Treaty
(rati ed in 1958) to the Single European Act (SEA, 1987), the Maastricht Treaty on
European Union (1993), and the Amsterdam Treaty (1999)—on the relations among
its three supranational institutions—the Commission of the European Communities,
the European Court of Justice, and the European Parliament—and between these
actors and the intergovernmental Council of Ministers. We conceive of these
institutions in terms of the roles they perform in the three core functions of the
modern state: to legislate and formulate policy (legislative branch), to administer
and implement policy (executive branch), and to interpret policy and adjudicate
disputes (judicial branch).