The establishment of democracy on both sides of the Atlantic has not been a smooth evolution towards an idealized presumed endpoint. Far from it, democratization has been marked by setbacks and victories, a process often referred to as ‘contested democracy’. In view of recent mobilizations such as the Arab Spring and the Occupy movement, in which new technologies have played a key role, there is a need for a renewed analysis of the long-term evolution of US and UK political systems. Using new areas of research, this book argues that the ideals and the practices of Anglo-American democracy can be best understood by studying diverse forms of participation, which go beyond classical expressions of contestation and dissent such as voting. The authors analyze political parties, social movements, communications and social media, governance, cultural diversity, identity politics, public-private actors and social cohesion to illustrate how the structure and context of popular participation play a significant role in whether, and when, citizens ́ efforts have any meaningful impact on those who exercise political power. In doing so, the authors take crucial steps towards understanding how a vigorous public sphere and popular sovereignty can be made to work in today’s global environment. This book will be of interest to students and scholars of political science, British and US history, democracy, political participation, governance, social movements and politics.