The debates of the 1990s over the causes of and responses to substate conflict were significant and wide ranging; there is now a sizable literature on ethnic conflict and civil war. But this literature makes few connections to long traditions of scholarly theorizing about collective violence in political science and in allied fields. This article examines two recent books by Mark Beissinger and Ashutosh Varshney that help turn mainstream theorizing about mass violence back toward its roots in problems of social order, state-society relations, and group mobilization. They break down the intellectual wall that has grown up between the study of something called "ethnic" or "nationalist conflict" and a long line of work on collective action in political sociology and cognate disciplines. These books are part of a new micropolitical turn in the field: a concern with uncovering the precise mechanisms by which individuals and groups go about trading in the benefits of stability for the inherently risky behavior associated with mass killing. The final section of the article assesses what such a turn might mean for research methods and theory making in comparative politics and international relations as a whole.