This state of global affairs has led many political theorists to question whether globalization is taking importance away from the nation-state as the primary actor in international relations. As we will see, there are those who believe that globalization is creating sweeping changes in the very fabric of human society and subverting the sovereignty of the nation-state. Proponents of this theory point to the effects of multinational corporations, non-profit organizations (NGOs) and new international political institutions like the International Criminal Court (ICC) or the International Monetary Fund (IMF) on the internal decision-making processes of national politicians and leaders.
At the other end of the spectrum are the skeptics who view globalization as a merely quantitative increase in economic trade between countries.  These skeptics reject the view that the increase in inter-state traffic costs the nation-state any of its former authority and consider the nation-state as the preeminent actor in international relations.
The prevailing opinion in South America seems to be that the process of globalization is increasing the challenges facing individual nations. As stated in the Comisión Estratégica de Reflexión of the Comunidad Sudamericana de Naciones, "En un período de reafirmación del Estado Nacional, la integración regional surge como un elemento indispensable de realización de nuestros proyectos nacionales de desarrollo." To increase national capacity, local governments are reaching beyond state boundaries to form transnational alliances and integrate their regions.
The concept of integration is abstract in that it cannot be observed and measured the same way as for example, a rock can. In its most general use though, integration refers to the movement of units from a state of isolation towards unification. When applied to the Nation-State integration refers to "a process of large-scale territorial differentiation characterised by the progressive lowering of internal boundaries and the possible rising of new external boundaries." 
Integration has traditionally been used in the context of economic and commercial integration but can also refer to the multidimensional processes of social, political, labor, or military cooperation between two or more countries.
For Dobson, integration is the "most intense form of inter-state interaction" and linked to increased levels of cooperation.  For Langenhove, et al, regional integration is "characterised by the intensification of relations between independent sovereign states that gives rise to some kind of structure for mutual cooperation based on recurring and stable patterns of behaviour, that is, to institutionalisation."  It can be described in terms of a gradual process with varying levels of cooperation and conflict given the issue in question but does not automatically imply consensus at every level. For example, it is possible for two nations to create a common customs union without agreeing on labor or environmental standards.
We will develop these ideas in the following sections where we will focus on contemporary international relations theories that can be used to analyze the process of regional integration in South America today. We will begin with definitions and a discussion of the regional integration theories of new and old regionalism, open and closed regionalism, globalization, 21st century Socialism, constructivism, and finally theories of realpolitik.
By Nathan Gill - Southern Affairs
1Maúrtua de Romaña, Oscar. Hacia la consolidación de la Comunidad Sudamericana de Naciones. Speech at FOPRI Forum Debate: Lima 28 Jan. 2005. 2Kissinger, Henry. Interview with Charlie Rose. The Charlie Rose Show. PBS. 23 Mar. 2007 3"Zimmerling, Ruth. Globalization and Democracy. Paper Prepared for the Annual Meeting of the Tampere Club. Tampere, Finland 18-20 Aug. 2003. 4 Comunidad Sudamericana de Naciones Comisión Estratégica de Reflexión. Un Nuevo Modelo de Integración de América del Sur: Hacia la Unión Sudamericana de Naciones. 2006
De Lombaerde, Philippe and Luk Van Langenhove. Indicators of Regional Integration: Conceptual and Methodological Issues. UNU-CRIS Occasional Papers 0-2004/15. 2004: 8
Dobson, Wendy. "Economic Policy Coordination: Requiem or Prologue?” in Policy
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Van Langenhove, Luk, Isabella Torta, and Ana-Cristina Costea. The Ascent of Regional Integration. UNU-CRIS Occasional Papers 0-2006-/5. 2006: 2.