This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. Just when we thought we'd survived the Culture Wars, the front lines in the Religious Freedom Wars are forming up. PEW reports religious restriction, in the form of both government and social hostility, has reached a six-year high. The structure of the book begins with the American experience, which is in many respects fundamental to the Canadian debate. The International Religious Freedom Act itself was launched under a Democratic administration in 1998, and has enjoyed no small measure of controversy. Canada's Prime Minister was equally clear when he launched the Office of Religious Freedom in February of 2013. The book is not primarily an argument about public policy or state offices, but an argument about how underlying issues of theory – how 'ideas' – can and do impact the practice of politics.