David Kertzer has built a distinguished career as a historian of Italy and, particularly, the modern papacy. Recent access to documents in the Vatican archives has led him to turn the bulk of his attention to the years of Pius XI and Pius XII. Historians and other readers whose interests connect to Kertzer's have come to appreciate his thoroughness and thoughtful work. His The Pope at War: The Secret History of Pius XII, Mussolini, and Hitler is no exception. For a long time to come, the student will be hard pressed to name a better book on the subject. Pius's relations during the Second World War with Adolf Hitler's and Benito Mussolini's regimes were complicated, although less so with the Germans. A suspicious tension always plagued affairs with Hitler's Berlin, as Eugenio Pacelli, the future Pius XII, had lived in Germany before the Nazis came to power and cultivated some fondness for that nation and its traditions, although this partiality never extended to Nazism. On the other hand, Pacelli was born and raised in Rome and, to state the obvious, the Vatican sits in Italy. Pacelli's Curia was stocked overwhelmingly with Italians. Relations were thus necessarily more intimate between the Holy See and Italy and ran more hot and cold than those with Germany. The liberal Italian kingdom destroyed the Papal States in order to achieve its nineteenth-century unification. The horrible state of affairs, however, ended with the 1929 Lateran Accords between the duce and Pius XI, which brought the Vatican closer to the regime. Their creation of the Vatican City State and the acknowledgment that Italy was a Catholic nation led Pius to praise Mussolini as a man of providence who gave Italy back to God. The Holy See also found some agreement with Fascism (and Nazism) in the pontiff's 1937 encyclical Divini Redemptoris, a sign that even the contentious Pius XI recognized that he and the two dictators shared valid anticommunist credentials. The Holy See, nonetheless, feuded with both regimes through the 1930s. Pius's 1931 encyclical Non abbiamo bisogno condemned Blackshirt violence, and his 1937 Mit brennender Sorge criticized Hitlerian racism. Mussolini's anti-Semitic measures in 1938 caused a final rupture between Italy and the pontificate of the ailing Pius. Kertzer explored these earlier links in his excellent study, The Pope and Mussolini, and he concludes the prologue of The Pope at War with, “For the Duce, Pius XI could not die soon enough” (xxxvii). With Europe collapsing into war, then, the newly elected Pius XII adopted a new course—to avoid “offending Hitler” while attempting to “remain on good terms” with Mussolini in order to rely on him as “his best bet for exercising a moderating influence” on Germany (474).

The Pope at War presents a treasure of new information on Pius XII's conduct toward the two dictators. Sometimes, however, Kertzer might have devoted more discussion to published sources. He dismisses Humani Generis Unitas, the aborted last encyclical of Pius XI that his successor squashed yet has been the subject of much analysis (see, for example, Frank J. Coppa, “The Hidden Encyclical of Pius XI Against Racism and Anti-Semitism Uncovered—Once Again! A Bibliographical Essay,” The Catholic Historical Review 84, no. 1 [1998]: 63–72). Poland provides another example. Kertzer uses meetings between the pontiff and the Cardinal-Primate August Hlond, to illustrate how Rome appeased the Germans even at the expense of other Catholics. Hlond came to Rome in late September of 1939 toward the end of the Nazi and Soviet conquest of his nation. At a Castel Gandolfo meeting, Pius “disappointed” the cardinal by not condemning the invasion (84–85). The following May, Hlond approached the pope to use the airwaves of Vatican Radio to deliver a message of hope to the Poles and again met disappointment. Pius responded that the time was inopportune (137–138). The Italian scholar, Raffaella Perin, however, recently noted that Hlond did, indeed, use Vatican Radio to address his countrymen, not in May of 1940 but on the earlier occasion. The Osservatore Romano published Hlond's text on October 2–3, 1939, that is, the day after the disappointing encounter at Castel Gandolfo (Raffaella Perin, La radio del papa, Propaganda e diplomazia nella seconda Guerra mondiale [Bologna: Il Mulino, 2017], 57). Pius's attitudes thus become more complicated.

The pontiff's approach to the Holocaust remains crucial to the whole story, and Kertzer concludes his work with an essay on “The Silence of the Pope.” While he emphasizes that Pius was not “Hitler's Pope,” the reluctance to intervene on behalf of the Jews will forever cast a dark shadow on his legacy. He justly portrays the wartime Pius as a failure in moral leadership, a failure of which he was acutely, and probably painfully, aware. Kertzer understandably focuses on Pius XII, although perhaps more consideration of the broader Catholic Church—and Catholics—yields a story both more complex and hopeful. He mentions figures such as the diabolical Wlodimir Ledóchowski or the idiotic Cesare Orsenigo but not the remarkable Jewish aid organization, DELASEM, that Italian priests informally took over to save it from the Nazis; or the heroic (and venerable) Giorgio La Pira who, hiding from the Germans in a Tuscan monastery gave up his room and slept in his car to make way for Jewish refugee children from Rome, a story told to me by one of those children. La Pira was a Catholic, inspired by the same principles as his pope. But La Pira knew what to do, and he did it.