Departing from the established literature connecting the political-institutional patterns of democracy with the quality of democracy, this book acknowledges that democracies, if they can be described as such, come in a wide range of formats. At the conceptual and theoretical level, the authors make an argument based on deliberation, redrawing power diffusion in terms of the four dimensions of proportionality, decentralisation, presidentialism and direct democracy, and considering the potential interactions between these aspects. Empirically, they assemble data on sixty-one democracies between 1990 and 2015 to assess the performance and legitimacy of democracy. Their findings demonstrate that while, for example, proportional power diffusion is associated with lower income inequality, there is no simple institutional solution to all societal problems. This book explains contemporary levels of power diffusion, their potential convergence and their manifestation at the subnational level in democracies including the United States, Switzerland, Germany and Austria.