Although significant effort has been devoted to establishing the institutionalization as a critical dimension of parties and party systems, empirical analyses of the political implications of this institutionalization have received relatively little scholarly attention. Little is known, for example, about how it promotes governments' programmatic consistency. This article contributes to this debate by investigating a common trait of Latin American politics-programmatic shifts endeavored by left-wing governments who take office in the midst of speculative attacks - and examining how different levels of institutionalization affect the probability of such changes occurring. Results show that, confronted by strong speculative pressure, left-wing presidents tend to abandon their campaign promises in favor of conservative economic agendas. Contrary to expected, however, these changes occur more frequently in institutionalized party systems.