New book lays out collusion between pope and Mussolini

In 1938, Pope Pius XI addressed a group of visitors to the Vatican. There were some people, he said, who argued that the state should be all-powerful - "totalitarian". Such an idea, he went on, was absurd, not because individual liberty was too precious to be surrendered, but because "if there is a totalitarian regime - in fact and by right - it is the regime of the church, because man belongs totally to the church".

As David Kertzer demonstrates repeatedly in this nuanced book, to be critical of fascism in Italy in the 1930s was not necessarily to be liberal or a lover of democracy. And to be anti-Semitic was not to be un-Christian. The pope told Mussolini that the church had long seen the need to "rein in the children of Israel" and to take "protective measures against their evil-doing". The Vatican and the fascist regime had many differences, but this they had in common.

Kertzer announces that the Catholic Church is generally portrayed as the courageous opponent of fascism, but this is an exaggeration. There is a counter-tradition: John Cornwell's fine book, Hitler's Pope, on Pius XII (who succeeded Pius XI in 1939) exposed the Vatican's culpable passivity in the face of the wartime persecution of Italian Jews. But Kertzer describes something more fundamental than a church leader's strategic decision to protect his flock rather than to speak up in defence of others.

His argument, presented not as polemic but as gripping storytelling, is that much of fascist ideology was inspired by Catholic tradition - the authoritarianism, the intolerance of opposition and the profound suspicion of the Jews.

Pius XI - formerly Achille Ratti, librarian, mountain-climber and admirer of Mark Twain - was elected pope in February 1922, eight months before Mussolini bullied his way to the Italian premiership. For 17 years the two men held sway over their separate spheres in Rome. In all that time they met only once, but they communicated ceaselessly by means of ambassadors and nuncios, through the press and via less publicly accountable go-betweens.

Kertzer has uncovered a fascinating tale of two irascible - and often irrational - potentates, and gives us an account of some murky intellectual finagling, and an often startling investigation of the exercise of power.

The accession of Mussolini, known in his youth as mangiaprete - priest-eater - didn't bode well for the papacy. The fascist squads had been beating up clerics and terrorising Catholic youth clubs. But Mussolini saw that he could use the church to legitimise his power, so he set about wooing the clergy. He had his wife and children baptised. He gave money for the restoration of churches. After two generations of secularism, there were once again to be crucifixes in Italy's courts and classrooms. Warily the pope became persuaded that with Mussolini's help Italy might become, once more, a "confessional state".