Based on extensive original research and detailed historical case studies, this book links historical institutional analysis and social movement theory to a study of political systems in which new ethnic cleavages have emerged. It studies the surprising transformation of indigenous peoples’ movements into viable political parties in the 1990s in four Latin American countries (Bolivia, Colombia, Ecuador, Venezuela) and their failure to succeed in two others (Argentina, Peru). The study concludes with the democratic implications of the emergence of this phenomenon in the context of declining public support for parties.