For policy makers and scholars to understand the objectives that Islamist activists hold and the policies that they are likely to pursue, they must first understand who Islamists are and they do. This article puts forth a definition of Islamism that focuses on discursive and institutional change as central Islamist ends, using episodes of Islamist activism in Lebanon and Yemen to illustrate important variation in the pursuit of these goals. Arguing that Islamist reforms both expand and contract the terms of national debate, the article cautions against exclusionary responses to Islamist activism, which can encourage the encroachment of authoritarianism. At a recent conference on US policy in the Middle East, I was asked by the organizers to address the thorny and question of what Islamists want.1 I say unpopular because while media characterizations of Islamist politics often include the gross aggregations implied by the question, scholars working on issues of Islamist activism tend to back away from such generalizations, focusing instead on explaining variations in Islamist practice as an outcome of some prior cause or set of causes. Doing so entails explaining the wide variety of forms that Islamist activism takes by focusing on differences in the institutional structure of the state, regime responses to Islamism, and the nature of the competitors that Islamists encounter in plural political settings, like parliaments and syndicates. Yet if identifying some cross-national and cross-organizational similarity amid this variety seems challenging, it is not entirely out of reach, embedded in Islamist discourse and practice. The goal of this article is to make an explicit case for it means to be an Islamist, on the logic that before scholars and policymakers can address the question of what Islamists it is important to define is meant by Islamism and who Islamists, as a distinct subset of political actors, may be. After offering a working definition of Islamism that can hold across cases, this article then examines two examples of recent Islamist activism. By focusing on who Islamists are and Islamist do (and with whom), it is then possible to address the difficult question of Islamists want, and to consider the attendant policy implications. Islamism and the Public Setting aside the vast institutional and ideological diversity across and within Islamist organizations, or questions regarding the locally-specific and tactically-differentiated goals of each organization, Islamists can be understood as actors who seek to transform the terms of public debate, whether institutionally or discursively. In the institutional realm, this means changing the formal rules that order the relationship between state and society, while discursive change is reflected in the informal rules and norms that give shape to this relationship. This definition, while not essentially differentiating Islamists from other political activists, also invites a discussion of Islamists' methods and means by focusing on the ways in which activists pursue their goals. There are a great many ancillary goals that differing Islamist organizations may hold - well beyond the ubiquitous call for the substantively vague of Shari'a - but each of these ancillary goals is in some way contingent upon the prior successful Islamization of the public. This concern with public transformation significantly predates the contemporary Islamist sahwa or the awakening of the post-Iranian Revolutionary moment. Without a doubt, today's Islamists were inspired by the success of the Iranian Revolution, but many also invoke a much older set of inspirational models - particularly from that earlier sahwa of the 19th century salafiyya movement - to locate their calls for both institutional and discursive reform as the precursor to policy change. When citing Jamal al-Din al-Afghani, with his focus on the critical importance of the just ruler, contemporary Islamists speak of an institutional Islamization that entails - and perhaps requires - a top-down approach, the implementation of rules and procedures that will properly order Islamic society. …