Integration theories after twentieth century: The new actors in international relations and transforming structure of sovereign nation-state

This article contends that most of the intellectual-academic works on Regional integration reflect major dichotomies between the theories of International Relations. During the first few decades of the integration processes, the core Regional integration debate involved idealism-oriented neo-functionalists and realism-oriented intergovernmentalist approaches; whereas the current scholarship on Regional integration mirrors the main division that has emerged within the discipline of International Relations since 1980's between rationalists regarding the integration process as the product of conscious member states' behaviour and constructivists focusing on policy-formation based on norms and common values. The main purpose of this article is to analyse the evolution of Regional integration after 20th Century within the context of the traditional and contemporary debates of International Relations. In this work it will be evaluated which strategies could practice of Regional integration and the new approaches on the judicial structure of international actors. As a result it has been exposed that the nature of International economy-political sistem, goes to a radical metamorphosis and changing because of this integration efforts and it was pregnantnature to the new Supranational constitutions. Keywords: Regional integration, Interdependence, Federalism, Funtionalism, Neo-functionalism, Intergovernmentalism.