This chapter summarizes the findings of the book and draws some theoretical lessons. First of all, it underlines the importance of focusing on party agency in the electoral and political achievements of parties alongside structural economic and social circumstances. The conclusion contends that both the internal operations of parties and the organizational linkages between parties and their constituencies are key determinants of electoral and political success and, in order to have a better understanding of these organizational dynamics, researchers should critically engage with the party typological approaches generated from the analysis of Western party systems. The chapter also highlights the importance of moving beyond the secular–religious polarization perspective in the analysis of Middle Eastern politics in general and Turkish parties in particular. Ultimately, the case of the JDP reveals that, if a post-Islamist political actor adopts populism and a 'personalistic mass party' approach, it can cope much more successfully with (secularist and other) elites and keep a broad and heterogeneous constituency together. But it is highly likely that this normalization through populism and a 'personalistic mass party' entails paying the cost of the post-Islamist party’s gradual transformation into a populist hegemonic party that drives the political system towards competitive authoritarianism.