In the past 10 years, state legislatures from across the political spectrum have passed or considered reforms aimed at reducing prison populations. The breadth of reform challenges social science scholarship that views mass incarceration as “locked-in” by political, social, and economic forces and, as such, presents an important area of scholarly inquiry. In this article, I argue that new research on reform should be animated by a sociopolitical perspective on punishment that developed out of social science research explaining the rise of mass incarceration. In particular, I pose research questions, hypotheses, and potential methodologies related to (1) the causes of the new moment of reform; (2) the variation in reform efforts; and (3) the process, content, and political effects of reform. I conclude by briefly summarizing what we know about the underlying rationales and strategies of this new moment.