Introduction

The introduction outlines the main conceptual innovations introduced by the book and its party-centric approach. The major turning points faced by anti-system parties from parliamentary entry to government participation are presented, as is the mixed method research strategy employed, which combines qualitative comparative analysis (QCA) and in-depth case studies. The first turning point is represented by the capacity to ensure repeated re-elections in parliament (electoral sustainability); the second turning point refers to the process of ideological moderation and/or the integration into cooperative interactions at the systemic level (evolution of party’s interaction streams); the third turning point focuses on the electoral impact of the transition to national government (post-incumbency electoral performance). Each turning point is investigated through the development of a specific analytical framework and by paying due attention to the agency of political parties themselves.