Introduction

At some point in the twentieth century, many democratic states in Europe and North America – long the bastions of democratic politics – have banned political parties. Banning a party may help defend democracies from those perceived as ‘enemies’ but proscription risks undermining foundational liberal democratic commitments to free association, free expression and the representation of all citizens in the public sphere. This chapter presents hypotheses, the research design and core findings of a book that explores why democracies address this dilemma in different ways. More specifically, it examines party bans, legalization of parties and failed party bans in Spain (Herri Batasuna and its successors), Britain (Sinn Féin and Republican Clubs) and Germany (Socialist Reich Party and National Democratic Party). Key findings are that while availability of effective alternatives to party bans and incentives for partisan party-ban-veto-players to cooperate with anti-system parties were not important explanations for party ban decisions, an anti-system parties’ ambiguity about the appropriateness of political violence facilitated securitization of such parties as an existential threat and this led to proscription if veto players adopted the securitization frame.