This essay studies the history of public religion in Canada from the period of the Second World War to the patriation of the Canadian Constitution of 1982 with its Charter of Rights and Freedoms. Through these years, Canada would be transformed from a self-proclaimed “Christian democracy” of denominational pluralism, through an interval of religious pluralism, to a secularist pluralism, based on the ways courts and politicians have applied the charter. Although attention will be given to the spectrum of world religions represented in Canada, the analysis focuses primarily on the predominant Christian churches to which most Canadians, including aboriginal peoples, belonged. Until the 1970s, Christianity, in its national denominations, presented the only religion with public functions beyond the private realm – in culture, social institutions, law, and politics. While surveying the life of the major Canadian churches, therefore, this study focuses on the public functions of religion, most specifically on the dialectic of religion and politics in both formal and informal constitutional discourse, as Canadians attempted to identify and legislate the fundamental principles, values, rights, institutions, and procedures by which they wished to be governed. It is argued that the records generated by constitutional debates and decisions, and especially the centrally important quest to define and constitutionally entrench human rights, illuminate most clearly the historic shifting in the relations of religion and politics, church and state, in Canada’s political culture, where the former public functions of the churches were challenged and displaced with a secularist liberal ideology and jurisprudence.