How should broadly liberal democratic societies stop illiberal and antidemocratic views from gaining influence while honouring liberal democratic values? This question has become particularly pressing after the recent successes of right-wing populist leaders and parties across Europe, in the US, and beyond. This book develops a normative account of liberal democratic self-defence that denounces the failures of real-world societies without excusing those supporting illiberal and antidemocratic political actors. This account is innovative in focusing not only on the role of the state but also on the duties of nonstate actors including citizens, partisans, and municipalities. Consequently, it also addresses cases where the central government has at least been partly captured by illiberal and antidemocratic agents. Gabriele Badano and Alasia Nuti''s approach builds on John Rawls''s treatment of political liberalism and his awareness of the need to ''contain'' unreasonable views, that is, views denying that society should treat every person as free and equal through a mutually acceptable system of social cooperation where pluralism is to be expected. The authors offer original solutions to vexed problems within political liberalism by putting forward a new account of the relation between ideal and non-ideal theory, explaining why it is justifiable to exclude unreasonable persons from the constituency of public reason, and showing that the strictures of public reason do not apply to those suffering from severe injustice. In doing so, the book further politicizes political liberalism and turns it into a framework that can insightfully respond to the challenges of real politics.