The populist challenge to constitutional democracy—and constitutionalism as its modus operandi—is significant and raises deep questions regarding the nature of modern democracy. A crucial question pertains to the challenge that our existing (but eroding) democratic systems faces. The way we perceive this challenge is essential for our descriptive and prescriptive contributions. The first, perhaps most widely embraced view, is to perceive populism as a ‘disease’, ‘deviation’, or ‘pathology’ of existing democracy. A second view understands contemporary ‘neo-populisms’ rather as one particular instance of a rather profound, complex, and long-term set of transformations of democracy. Where we stand on this matter is of great importance, as the feasibility and potential success of our responses and solutions depend on our description of the problem. Many of the contributions to this special issue clearly go beyond the current state-of-the-art, in which populism and constitutionalism are often seen as mutually exclusive categories. The special issue provides ample reflection on intrinsic problems in constitutional democracy itself, and, taken as a whole, stimulates a self-reflexive and historically informed scrutiny of the modern projects of liberal democracy and constitutionalism, so as to provide due acknowledgement of the political and conflictive origins of the project, as well as of its current deficits.