This study explores the underlying causes of the processes of democratic reform in Japan and Korea over the past decade. In both nations, elite-challenging pressures from below have been the stimulus forcing reforms on the governing elites. For this reason, changes in mass attitudes and values become a crucial explanatory variable in accounting for recent political reforms. The authors discuss the pattern of political development in these two nations and their theory of how and why values are changing from an authoritarian to libertarian set of attitudinal orientations. This pattern of value change has been eroding the traditional tolerance of the mass publics in these two nations for authoritarian and corrupt practices. The authors empirically demonstrate how and why values have been changing and how these changes are related to increasing levels of elite-challenging protest potential and leftist reform-oriented attitudes.