Pope Pius xii was by far the most controversial pope of the past century. The vast literature about his pontificate, written over the last sixty years, almost equally by admirers or critics, shows no sign of abating. But the reader needs to be aware of two overall considerations. First, the incessant partisanship of the so-called Pius wars is fuelled less by historical objectivity than by polemical or political purposes: second, the all-important records of his pontificate are still not yet open to public scrutiny in the Vatican archives. When they eventually become available, they will necessitate at least a revision or a complete re-writing of all previous assessments. Both the books under review must therefore be considered incomplete.

Gordon Thomas's retelling of the highly dramatic months in 1943–4 after Rome was occupied by German troops but before its liberation by the Allies is composed in flash-back form, with vivid short episodes taking place one after another in various parts of the city. His main claim, however, that Pope Pius had a secret plan to assist the Jews of Rome, still lacks verification. Thomas provides no sources but relies on the oral testimony of survivors. He seeks to prove that the pope had a long affinity with the Jewish colony on the other side of the Tiber, and sought to assist them clandestinely by all possible means. His instructions were supposedly given orally. But while many Jews were given refuge in Catholic institutions, Thomas's assertion that this was Pius' top priority lacks substantiation, which may or may not be found in the Vatican archives.

Ventresca's more conventionally organised and excellently researched biography places the heated debates about Pius' war-time policies in the wider context of his lengthy service as a Vatican bureaucrat. Eugenio Pacelli had a swift rise through the ranks of the Vatican's diplomatic service. Ventresca rightly stresses the significance of his first posting abroad to Germany, and his subsequent commitment to the diplomatic resolution of international conflicts. After his election as pope in March 1939, he spent six intensive months deploying the Vatican's influence on behalf of peace. In vain.

The outbreak of war in September 1939 demonstrated not only the failure of Pius' diplomacy, but also the even more fateful powerlessness of the Vatican. Pius quickly adopted a policy of impartiality, even though this stance was to cause disappointment amongst all those who called for papal protests against the crimes of the aggressors. What the available evidence so far shows is that Pius was consistently tormented by the sufferings of all the war's victims, and by his inability to alleviate their plight. At the same time, he also clung to the Vatican's stance of neutrality in the vain hope that his diplomatic skills would be required as a mediator to bring hostilities to a close. For these reasons, and after much agonising thought, he adopted a prudential reserve and refusal to condemn war crimes lest speaking out could lead to even worse consequences for the victims, or preclude his efforts to stop the war. Predictably such a stance evoked strong criticism at the time and since from those who wanted to see the pope's moral authority used to condemn both Nazi and Soviet crimes. Particularly after the escalation of the Nazi crimes against the Jews, ever stronger demands were made to have the pope intervene. Inevitably the charge that the pope's reserve meant that he was indifferent to these sufferings grew louder.

Ventresca defends Pius against accusations of moral cowardice by pointing to his highly secret talks in early 1940 with members of the German resistance hoping to restore a unified Germany freed of the Nazi scourge. At the same time, Ventresca describes the ambivalent results when strong remonstrations were made behind the scenes, as for example in Slovakia, where the papal representative was instructed to protest fiercely to the president, who happened to be a Catholic priest. As one Vatican official commented, ‘Everyone knows we can't bring Hitler to heel. But who would believe that we can't even control a Catholic priest?’ Yet, where there was no threat of reprisal, the pope could in fact speak out forcibly, as for example against the American bombing of Rome and other Italian cities.

Ventresca leaves open the question whether this stance was appropriate. But he notes that even after the war Pius expressed no acknowledgement or comfort to the persecuted Jews, and refused to accept the premise of Christian responsibility for Hitler's crimes, or the collective guilt of the German people. Instead, Ventresca suggests, the Vatican crafted a dossier of what the pope had done to assist the Jews in Rome, along with the frequent expressions of gratitude by Jewish leaders, who came seeking support for the new state of Israel, or even for its diplomatic recognition by the Vatican.

During the remaining years of his reign, Pius became obsessed by the dangers of Communism, which had already seized control of eastern Europe, and threatened the same in Italy, France and Spain. Yet his vigorous denunciations of the ideology did not prevent careful approaches to these governments seeking some form of accommodation and relief for the Catholic Church. But he also strongly defended those Catholic leaders such as Cardinals Stepinac, Wyszynski and Mindszenty, whom he saw as victims of Communist vendettas. Rejecting Marxist extremism, he called for a truly Christian social order which would enhance human dignity and freedom.

In his final assessment Ventresca warns against wishful thinking. He clearly feels that Pius' unwillingness to condemn the Nazis' treatment of the Jews was a moral failure, compounded by the absence of any post-war atonement or reconciliation. But whether any other policy would have saved more lives is still an unresolved question, perhaps to be answered in part when the Vatican archives are finally opened.