What drives party-based Euroscepticism and why are some small parties Eurosceptic, even if they are not located in the margins, whilst other marginal parties are not? What makes mainstream opposition parties careful not to appear Eurosceptic? Is Euroscepticism an aberration of politics, an extreme populist ideology, or just politics as usual? These are some of the topics explored in Political Parties and Euroscepticism. Drawing on a variety of historical accounts, comparative case studies and textual analysis of over 150 party manifestos, this book examines party-based Euroscepticism as an electoral strategy and offers a dynamic theoretical model for analysis. It uses case studies from three West European countries to examine the role of domestic electoral systems and party location as explanatory variables in the theoretical model. Euroscepticism offers a lifeline to some parties, whilst it sucks the oxygen from others. It is a strategy that pays off only under certain conditions. This book investigates the conditions under which it works and those under which it doesn't.