This book looks at the theoretical issue of how a democracy can defend itself from those wishing to subvert or destroy it without being required to take measures that would impinge upon the basic principles of the democratic idea. It links social and institutional perspectives to the study, and includes a case study of the Israeli response to Jewish extremism and violence, which tests the theoretical framework outlined in the first chapter. There is an extensive diachronic scrutiny of the state’s response to extremist political parties, violent organizations and the infrastructure of extremism and intolerance within Israeli society. The book emphasises the dynamics of the response and the factors that encourage or discourage the shift from less democratic and more democratic models of response. An electronic edition of this book is freely available under a Creative Commons (CC BY-NC-ND) licence. — .