To understand European Union (EU) policy in the realm of immigration and asylum, it is helpful to first distinguish Europe's historical developments in this area. Through World War II, European countries remained primarily sites of emigration. The end of the Cold War triggered the final phase in European migration. Political instability in Eastern Europe in the wake of the fall of communism led to an increase in migration in the early 1990s. The European Parliament – still excluded from the policy process before the Lisbon Treaty's designation of the co-decision process — has been involved in legislation since the passage of the 2008 Return Directive. The consequence of EU competence since Maastricht has been new policies across a breadth of issue areas, as contemplated by the treaties. The EU remains far from demonstrating a uniform, coherent, comprehensive system of policies across its member states.