Effective deliberation is central to democracy and so should enter any definition of democratization. However, the deliberative aspect now ubiquitous in the theory, practice, and promotion of democracy is generally missing in comparative studies of democratization. Deliberation capacity can be distributed in variable ways in the deliberative systems of states and other polities. A framework is described for locating and analyzing the contributions of its components and so evaluating the degree to which a polity’s deliberative system is authentic, inclusive, and consequential. An emphasis on deliberation reveals important determinants of democratic transition and consolidation, thereby providing substantial explanatory as well as evaluative and normative purchase.