This is an open access title. It is available to read and download as a free PDF version on Oxford Academic and is made available under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International licence.Political actors who challenge democratic fundamentals have been present for some time, yet democracies still struggle to determine how best to respond to them. Should antidemocrats be excluded, at the risk of violating core democratic principles such as equal representation and pluralism, or should they be included, potentially leading to further democratic backsliding and erosion?Despite the urgency of this dilemma, democratic theory has largely focused on defending militant democracy – the practice of excluding antidemocratic actors – while paying less attention to alternatives. Responses based on toleration are often dismissed, even though they are more widely practiced. Meanwhile, social approaches, which seek to counter anti-democrats by addressing the structural injustices they exploit, remain relatively unexplored.Democratic Self-Defence examines militant democracy alongside these lesser-known approaches to democratic self-defence. It identifies three broad rationales for responding to antidemocratic forces: repression-centred militant democracy, toleration-based approaches, and egalitarian social inclusion. Treating these rationales as ideal types grounded in distinct normative principles, the book analyses their conceptual boundaries and internal logics, as well as their respective advantages, limitations, and interrelationships. Each approach differs in how it defines democratic threats, the strategies it endorses, and the goals it pursues. Each also finds expression across institutional contexts ranging from state practices and party politics to grassroots action.By offering an all-encompassing and critical overview of a field that is currently fragmented, the book clarifies how fundamental conceptions of democracy inform strategies of democratic self-defence, determining who is classified as an "antidemocratic actor" and which aspects of democracy are deemed worthy of protection. In doing so, it broadens the repertoire of responses available to democracies and deepens our understanding of what democracy really means and how it can be defended.