Chile's 1980 Constitution embodied the political aspirations of the nation's military regime. Before democratization, the constitution underwent a process of reform that did away with some of its most blatantly authoritarian provisions but preserved a set of institutions that would characterize and constrain the regained Chilean democracy. This article presents an account of that process. It juxtaposes two theoretical perspectives: one that sees the results as determined primarily by the power relationship of the participants, and one that stresses contextual factors, such as institutional traditions. This study argues that while the Chilean case largely confirms the importance of the existing constitution for the outcome, the final outcome depended nonetheless on the participants' assessment of the relations of power, and therefore might have been open to different results.