Since the 1940s issues pertaining to the separation of Church and State have been among the most contested and complicated in American society. In recent years controversy has centred on the constitutionality of faith-based initiatives, the display of religious symbols in public places, financial aid to parochial schools and the teaching of intelligent design in public schools. Building on three earlier books that analyse Church-State relations in the United States, in The third disestablishment, Steven K. Green, who teaches courses in law and history at Willamette University in Oregon and directs its Center for Religion, Law and Democracy, helps to set today's controversies in a constitutional, political, historical and cultural context.

Green's insightful, illuminating examination of the debates over the separation of Church and State focuses on pivotal Supreme Court cases in the years from 1940 to 1975 that both established rules for the funding and practice of religion in the United States and shaped Americans’ understanding of Church-State issues. He argues that this thirty-five-year period constitutes a third ‘transformative era in church-state attitudes and relations’ (p. 14). It followed two earlier disestablishments of the Church – the founding era that produced the First Amendment and the Church's ‘legal and political disestablishment’ during the nineteenth century (p. 14). As the result of this third disestablishment, which involved a slow evolution from the court's embracing of separationism to ‘its legal and cultural displacement’, Americans ‘now live in a post-separationist era’ (p. 15).

Green explains that in their rationales for two very controversial decisions – Everson v. Board of Education (1947) and McCollum v. Board of Education (1948) – the justices expressed a ‘strict separationist’ position on the First Amendment's non-establishment principle. Writing for the majority in Everson, Justice Hugo Black argued, citing Thomas Jefferson's 1802 Letter to the Danbury Baptists, that this principle ‘intended to erect “a wall of separation between church and state”’. In justifying McCollum, the justices added that the First Amendment imposed a ‘high and impregnable wall’ between Church and State. These two rulings, Green contends, introduced an interpretative perspective that ‘governed church-state controversies for the next four decades’ (p. 4). Two additional ground-breaking cases – Engel v. Vitale (1962) and Abingdon School District v. Schempp (1963) – reinforced the widespread ‘perception that the justices had imposed a secularist, separationist regime on an unwilling populace’ (p. 4).

Supporters of the court's separationist interpretation asserted that it was consistent with the views of Jefferson and James Madison, helped to maintain American democracy and prevented religious conflict. Critics countered that this perspective clashed with the nation's history and practices, contradicted the intention of the Founders, was antagonistic to the nation's religious institutions and the faith of most Americans, and promoted secularism as the basic principle for ordering American society. Opponents also protested that the court's espousal of the separationist position misconstrued the purpose of the Establishment Clause, which was to prohibit the establishing of a national Church or giving preferential treatment to one religious group, not to prevent the government from assisting or cooperating with all faith communities.

Green judiciously analyses the arguments used by the key individuals and organisations in this debate over the meaning of the separation of Church and State and the court's key decisions on matters related to this concept – the journalist Paul Blanshard, the Catholic theologian John Courtney Murray, the neo-Orthodox theologian Reinhold Niebuhr, the Christian Century editor Charles Clayton Morrison, Protestants and Other Americans United for the Separation of Church and State, the American Civil Liberties Union, the National Catholic Welfare Conference and the National Association of Evangelicals.

Green contends that neither Jefferson, Madison, nineteenth-century nativists, militant Protestants, secularists nor Supreme Court justices created the contemporary principle of separationism. No institution, group or movement invented this concept. Green carefully explicates the various constitutional, political, historical and cultural concepts and contexts, which contributed to separationism.

Green makes three claims. First, ‘the metaphor of “a wall of separation between church and state,” which came to embody the concept’, was not critical to justices’ rulings but rather was an afterthought (p. 10). Second, although the justices appeared to be of one mind in the Everson and McCollum cases, they never agreed on what separation meant. This enabled ‘the competing position of religious cooperation and accommodation’ – defended by Murray and others – to prevail in both the culture and at the Supreme Court by the 1980s (p. 11). Third, the conflict between Protestants and Catholics in the 1940s and 1950s was much greater than most scholars recognise today and its impact on popular perceptions of these two faith communities lasted longer than the particular issues that generated the conflict.

This third claim leads to Green's principal thesis: the substantial conflict between Protestants and Catholics during the 1940s and 1950s had only secondary importance in ‘the larger debate over the public role of religion in public life’ and ‘limited impact on the development of church-state jurisprudence’ (p. 13). The major issue instead was widespread concern about the secularisation of American culture and social institutions, especially public schools. After the Supreme Court ruled in 1962–3 that prayer and Bible-reading in public schools was unconstitutional, much of the Protestant support for the separationist position dissipated and the challenge of secularism rather that the threat of Catholicism became the major factor in the debate over Church-State relations. During the 1960s the changes to Catholicism adopted by Vatican II, the programmes of Lyndon Johnson's Great Society and the civil rights movement intensified debate over whether America's religious pluralism could effectively replace Protestantism as a cultural bulwark to stem the tide of secularism. Concerns about religious instruction in public schools and aid to parochial schools were emblems of the deeper social conflict over whether religious or secular values would prevail in the United States.

Green's account of Church-State issues in the mid-twentieth century is comprehensive, coherent and compelling. Based on extensive research in primary sources and brimming with astute analysis, The third disestablishment greatly enhances our understanding of the relationship between America's government and its religious institutions and communities.