This book explains how and why conspiracy theories have become such a powerful political weapon. From stolen-election claims to vaccine scepticism and global “elite” plots, conspiracy theories have moved from the political margins to the centre of public life. In an era of polarised politics, digital campaigning, and democratic backsliding, they increasingly shape elections, mobilise voters, and undermine trust in institutions. Organised around four core themes, the volume analyses the political logic of conspiracy theories, their impact on democratic governance, and the challenges they pose to public debate. It presents original empirical case studies of conspiratorial narratives circulating during election campaigns and across social media, and examines the role of political entrepreneurs, parties, and far-right movements in producing and amplifying them. By bringing together insights from political theory, sociology, political science and empirical research, this book offers a compelling framework for understanding conspiracy theories as a defining feature of contemporary political conflict. It is essential reading for scholars and students of political sociology, comparative politics, and cultural studies. Drawing on shared theoretical foundations across multiple disciplines, this book provides a comprehensive account of conspiracy theories as a central feature of contemporary politics.