Thesis advisor: David Deese / In recent years, the rise in the formation of regional organizations such as the North American Free Trade Agreement (NAFTA) and the Mercado Común Del Sur (Mercosur) has drawn an increasing amount of attention from political scientists and economists. However, countries preparing for entry into regional organizations have the challenging task of promoting both economic and social integration. When preparing for accession into regional organizations, Mexico and Argentina implemented multiple changes in their economic and political practices. As a result of these changes, citizens who perceived themselves to be excluded from the benefits of regional integration formed social movements such as the Zapatista Army for National Liberation and El Movimiento de las Mujeres en Lucha to voice their opposition. This thesis explores the policy changes made as Mexico and Argentina prepared for accession into regional organizations, the social movements formed in opposition to these changes, and the responses formulated by Mexico's and Argentina's leaders in reaction to these movements. I conclude that countries preparing for entry into regional organizations must implement policies which address the political concerns of these groups, rather than simply their economic concerns. Failure to do so will lead to deep social divisions which will hinder the formation and development of regional organizations. / Thesis (BA) — Boston College, 2008. / Submitted to: Boston College. College of Arts and Sciences. / Discipline: Political Science. / Discipline: Political Science Honors Program. / Discipline: College Honors Program.