Populism has become a favourite catchword for mass media and politicians faced with the challenge of protest parties or movements. It has often been equated with radical right leaders or parties. This volume offers a different perspective and underlines that populism is an ambiguous but constitutive component of democratic systems torn between their ideology (government of the people, by the people, for the people) and their actual functioning, characterised by the role of the elites and the limits put on the popular will by liberal constitutionalism.