Are liberal democracies in decline? If they are, what role does populism play in this? What can and should democracies do to defend their core features against ‘democratic decay’? And which features can be considered essential? These are difficult questions further complicated by the realisation that their answers depend on perspective. Populism and democratic decay are global phenomena but they play out differently in different countries and regions. They also cannot be properly understood through the lens of one discipline alone. This book brings together scholars of political science and law, who look at populism, democratic decay, and possible means to protect democratic constitutionalism from global, regional (European) and national angles. The book is made up of two parts. The first part discusses general aspects of populism. The second part of the book consists of seven country reports and one regional report; each analysing the success or failure of national constitutional safeguards against populism in the local constitutional and socio-political context. From East-Central Europe to the United Kingdom, from Italy to the Philippines, the pictures painted in these articles are diverse, yet enlightening and relevant from a comparative perspective. This volume is part of a research project on populism and democracy conducted at Maastricht University, Faculty of Law, and funded by the Statesman Thorbecke Fund at the Dutch Royal Academy of Sciences (knaw).