Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Political Science, 2007.Includes bibliographical references (leaves 190-202).Ever since Latin American economies collapsed in the 1980s and early 1990s, traditional redistributive programs began to coexist with new anti-poverty programs that usually took the form of conditional cash transfers (CCT). I examine the effects of the Mexican Education, Health, and Nutrition program (Progresa), the first and largest CCT implemented in the region, on electoral behavior. I argue that Progresa not only was substantially different from traditional clientelism, but that it challenged local monopolies on political power by increasing voter's income and giving recipients implicit and explicit information about its non-political nature. This weakening of monopolies, in turn, gave political parties incentives to compete for the votes of Progresa recipients. As a consequence, recipients increased their electoral participation, at least in the short term, and clientelism was irrevocably eroded. Despite the increased competition, however, recipients rewarded parties that proposed and retained Progresa. My understanding of Progresa's electoral effects is based on theory, field research on four villages, interviews with Progresa's designers and personnel, and analysis of media sources from 1996 until 2003. To test this argument, I use the Mexico 2000 Panel Study; aggregate data at the municipality level from 1997-2003; and to explicitly deal with the historic correlation between poverty, rural residence, and support for the seventy-year incumbent party, Institutional Revolutionary Party, I take advantage of the fact that early assignment of program benefits included a randomized component originally designed to evaluate the program effects on schooling and health.by Ana Lorena De La O Torres.Ph.D