Contrary to the situation in Europe, the research of political parties` internal structure in Latin America has been rather limited. Moreover, comparative research on party membership is virtually inexistent (Levitsky 2001; Wills-Otero 2009; see Alcántara and Freidenberg 2001; Webb and White 2007; Alenda 2011; Ponce 2013; Ruth 2013 for some exceptions and Combes 2011; Muñoz Armenta and Pulido Gómez 2010 for case studies on Mexico). The goal of this paper is to contribute to fill this gap that evidences this area of study of party politics from the perspective of party membership. To achieve this goal, I examine the statutes of the principal political parties in Latin America and analyse the role given to the party members in approximately 60 political parties in the region. I organize this information according to three dimensions and, based on this, I propose a classification of the capacity of influence of party members (in formal terms). First, I explore the conditions that the persons interested to become party members have to accomplish. Second, I look at the role party members have with respect to the internal democracy, i.e., candidate selection and programme formulation. Third, I analyze the extent to what party members can control party elites. This paper consitutes the first part of a larger project which will be complemented with an expert survey on party strategies regarding the role and influence of party members (second part) and with a field work consisting of interviews to grassroots party members (in particular abous its motivations and ideological positions) from various political parties-case studies selected based on the first and second part of the project.
