Paolo Zanini’s volume is part of a layered historiographical tradition that has investigated the relationship between Protestantism and Italian history from the Risorgimento to the second half of the 20th century. The classic works of Giorgio Spini, together with contributions by Pietro Scoppola, Renato Moro, Maria Paiano, and Kevin Madigan, have clarified how anti-Protestantism in Italy was a phenomenon closely linked to the processes of state-building, Catholic nationalism, and the balance of power between the Church and political authorities. Nevertheless, as Zanini observes, there remained an interpretative gap regarding the way in which the Protestant presence was perceived and administered in Italy during the Fascist era and the post-World War II period, especially from the point of view of religious freedom.

The main merit of the volume lies precisely in addressing this issue from a long-term perspective, showing how and why Protestantism became a “public problem” during the 20th century: not only on a religious level, but also politically, administratively, and in terms of public order. The chosen time frame – from the consistently with post-World War II period to the mid-1950s – allows the author to follow the transition from an authoritarian regime to a constitutional republican system, without falling into the temptation of reading this transition as a clear break.

From a methodological point of view, the work is striking for the breadth and quality of its documentary basis. Zanini cross-references civil and ecclesiastical sources, both central and peripheral: from the Central State Archives to the Archivio Apostolico Vaticano, from diocesan and prefectural archives to sources from Protestant minorities, such as those of the Waldensian Table. This plurality makes it possible to hold together the level of institutional decisions and that of concrete practices, avoiding both an exclusively “top-down” history and a fragmentation into unconnected micro-histories. The result is a dense reconstruction, capable of restoring the complexity of the actors in the field. Italy – and Rome in particular – emerges as a privileged observatory. The presence of the papacy, the freedom-destroying nature of the fascist regime, the country’s strategic role in the Cold War scenario, and the perception of Italy as a mission field for international Protestant churches help explain the intensity of the conflict. Defending Italy meant, in Catholic rhetoric, defending the very heart of Christianity, and therefore repelling a “danger” systematically associated with foreignness, the foreigner, and the subversive (ch. 1).

Fascism represented a decisive turning point. Thanks to the Lateran Pacts of 1929, Catholicism obtained a legal framework that strengthened its position as the official religion of the state and made it possible to translate confessional hegemony into administrative practices and repressive measures. Zanini clearly shows how, starting in the 1930s, the campaign against Protestant “heresy” was conducted in close synergy between ecclesiastical and civil authorities, thanks in part to the actions of the apostolic nuncio in Italy, Francesco Borgongini Duca, and the undersecretary of the Ministry of the Interior, Guido Buffarini Guidi. The Albertine Statute of 1848 and the Concordat of 1929 were used as legal and political instruments to reiterate that religious denominations other than Catholicism, although formally tolerated, had to remain confined to the private sphere.

The political and ecclesiastical authorities paid particular attention to Pentecostals, who were perceived as the most “dangerous” segment of the evangelical world. Their emotional, participatory, and loosely hierarchical religiosity appeared threatening not only on a doctrinal level but also on a social one. Pentecostals managed to penetrate the working classes, especially in the South, and seemed to undermine the established balance, thus becoming a litmus test for the fears shared by the state and the Church: fear of loss of social control, fear of instability, and fear of grassroots mobilization. The Buffarini Guidi circular of 1935, which effectively criminalized many Pentecostal activities, was one of the most eloquent examples of this repressive convergence (ch. 2).

Another area of conflict, clearly highlighted by the author, is that of assistance and charity, especially after World War II. The presence of Protestant organizations engaged in helping displaced persons, children, and the sick – often in connection with international networks – provoked a strong Catholic reaction, amid fears that such initiatives were nothing more than instruments of disguised proselytism. Underlying this, however, is a deep mistrust of the traditional religiosity of the peasant classes: a religiosity celebrated as spontaneous and deeply rooted, but at the same time judged to be fragile, superstitious, and easily influenced.

Zanini also subtly captures a broader unease, less explicit in the sources but constantly present: the fear of secularization. The processes of social and geographical mobility – from emigration from the countryside to the cities, from the South to the Center-North – fueled the perception of a breakdown in traditional forms of religious anchoring. This context saw both the promotion of certain popular devotions, primarily that of the Virgin Mary, and massive investment in the construction of new parishes in urban suburbs, interpreted as bulwarks against secularization and Protestant proselytism. One of the most original contributions of the volume, however, concerns the post-world war II period. The author shows how the transition to the new constitutional order did not bring about an immediate change and highlights the persistence of administrative cultures, police practices, and restrictive interpretations of religious freedom. The Christian Democrat-led governments engaged in a difficult mediation between the Vatican, internal order requirements, and international balances, especially in the context of the Atlantic Alliance and the privileged relationship with the United States. In this context, the fight against Protestant proselytism was often framed in anti-communist rather than anti-American terms.

It was only in the first half of the 1950s, thanks in part to the intervention of the judiciary, that the Buffarini Guidi circular and other repressive instruments began to be gradually dismantled. Zanini rightly points out that this process was far from straightforward at the administrative level. On the religious front, the transition from anti-Protestant campaigns to ecumenical initiatives coincided with the end of Pius XII’s pontificate and involved the same protagonists who, in previous years, as in the case of Igino Giordani, had moved in the opposite direction, testifying to a transition made up more of adaptations than of ruptures (ch. 3). Ultimately, The Protestant Peril offers a balanced reconstruction free of teleology. The conquest of religious freedom does not emerge as an inevitable outcome of modern society, but as a field of conflict, marked by advances and setbacks. The state constantly appears as a non-neutral actor and the Church as a subject capable of flexibly using the political and legal instruments at its disposal. The volume therefore represents a significant contribution not only to the history of Protestant minorities but also more generally to the understanding of the relationship between Catholicism, the state, and religious pluralism in contemporary Italy.