David Kertzer's latest work, The Pope at War, recounts the initial years of the papacy of Pius XII from his election in 1939 to the liberation of Italy in 1945. With it, Kertzer plunges into what historian Robert Ventresca has dubbed the ‘Pius Wars’ – the long-ranging, often furious debate about what the Holy See did and did not do during the Second World War and the Shoah. Those familiar with the field know that at one extreme is work that characterises Pius XII as ‘Hitler's Pope’, an antisemite sympathetic to Nazism, indifferent to or even actively complicit in the plight of Europe's Jews, while at the other is the portrait of a pope who secretly did everything he could to save Jewish lives and deserving of sainthood for his aid to victims of Nazi and Fascist violence. Most serious scholarship has fallen somewhere in the middle, with detractors and defenders alike confident that the opening of the Vatican archives relative to Pius XII's pontificate would lend support to their positions.

Those archives are now open, and Kertzer brings to the debate not only explosive new evidence culled from them but also extensive and meticulous research in diaries, correspondence, and the holdings of a variety of British, Italian, French, German and US archives for the period in question. These he weaves together to offer a gripping panorama of Italy at war, particularly as viewed from the Holy See. In the telling, he establishes an unflinchingly damning account of the Vatican's moral failing in the face of the outbreak of the Second World War and the ensuing mass murder of European Jews.

Organised chronologically, the book begins with the death of Pius XI in February 1939 – just as he was preparing to deliver a condemnation of Nazi racial policy. Cardinal Eugenio Pacelli, then Vatican secretary of state and soon-to-be-elected Pius XII, oversaw the suppression and subsequent destruction of all copies of the deceased pope's remarks. This act foreshadowed a cautious, conciliatory approach to the Nazi and Fascist regimes that would last throughout the war; it was the first of many times when Pius XII would decide that it was ‘best to say nothing’ (p. 387). He chose not to denounce the Nazi and Soviet invasion of Poland and maintained his silence as the Nazis turned westward. When Fascist Italy joined the war, the Italian church urged its faithful to do their patriotic duty and support the war effort. The book provides clear evidence that Pius XII was well informed from early in the war about Axis atrocities, and that he received ‘detailed reports of Hitler's campaign to exterminate Europe's Jews’ from multiple sources whom he deemed absolutely credible (p. 224). Nonetheless, he chose again and again to say nothing or to carefully craft any statements for maximum obscurity. ‘I am profoundly and firmly convinced’ – Kertzer quotes him as saying about one such occasion – ‘that I have done my precise duty taking care not to offend anyone, avoiding any particular references. Indeed, studiously taking care to say the least possible’ (p. 134).

Repeated pleas for the pope to repudiate the Axis or at least to speak plainly to condemn the unfolding genocide were rebuffed or left unanswered. Even when the Nazis occupied Italy in 1943 and began the roundup and deportation of Italian Jews, including those of Rome, Kertzer demonstrates that efforts by the Holy See to intervene on their behalf were mainly limited to Jewish converts to Catholicism and the children of ‘mixed’ marriages – especially those of some prominence or with connections to the Vatican. He acknowledges that many Jews and other refugees were hidden in church properties during the occupation and that Pius XII was certainly aware of this. However, Kertzer finds no evidence that Pius XII directed it, and he finds many examples of Catholic institutions turning Jews away.

The silence and circumspection during the first years of the war, Kertzer concludes, stemmed from Pius XII's conviction that the Axis powers would win. ‘He felt he needed to prepare for a future in which Germany would dominate continental Europe’, and he believed that his most important duty ‘was to protect the institutional church’ (p. 474). Even as the tide turned against the Axis after 1942, however, the Vatican's approach changed very little. Kertzer argues that this was due in part to fears for the fate of the church following a Soviet victory, but also because throughout the conflagration Pius XII feared alienating those Catholics who were loyal citizens of the Reich.

While Kertzer's account contains new and shocking revelations along the way, it is his careful articulation and analysis of the simultaneous construction of postwar memory that is the most thought-provoking aspect of his study. This thread runs subtly throughout the book but is devastatingly brought into focus in an epilogue that with great economy of expression describes a postwar ‘forgetting’ and a recasting of recent history that was actively participated in not only by the church but also by Italian society more generally. Even the victorious Western Allies had reasons during the onset of the Cold War for promoting a narrative in which a benevolent pope suffered alongside the faithful while guiding the church in secret solidarity with those who fought against totalitarianism. This brief coverage of the immediate postwar serves to remind us that the battle lines of the ‘Pius Wars’ were being drawn even during the events in question, and the hundreds of articles, monographs, memoirs and fictionalised accounts that have staked out positions since 1945 have been shaped by the Vatican's self-conscious and self-serving characterisation of its own integrity. Upon reaching its end, one realises that Kertzer's book has also been about this. It convincingly demonstrates how all of the building blocks of the most benevolent views of the pope at war – from the careful distinction between religious and racial antisemitism that discourages consideration of how the former fed the latter, to the conviction that it would have somehow been more dangerous for Jews and other victims of Nazism had the Holy See spoken out, to the belief that everything that could be done was being done but cloaked in necessary shadow – are themselves elements of a narrative spun to protect the church as an institution even as the pope stood by as millions suffered and died at the hands of the Nazis and their collaborators.