Why did the pope support Mussolini?

Answer 1

The Lateran Pacts of 1929 gave the Pope sovereign rights to a state of his own in the Vatican City, this would have given him independance from the Kingdom of Italy and would have shown the world that he was not under Mussolini's control. Il Duce had to give up ever attaining a complete totalitiarian, secular state with the Pacts, however what they did do was eliminate the Catholic Church as a political rival, making them dissolve the PPI and the Catholic Scout Movement. The Pope didn't completely support Mussolini afterwards anyway, they still conflicted over the suppression of Catholic Action and the racial laws of 1938.

Answer 2

The Catholic Church was in danger of losing all of its land in Rome. Through the middle ages it held control over vast tracts of land, but by the 1920s even its claim to Vatican City was disputed. Mussolini offered the church a deal - he would recognize the Church's right to independence and their ownership of the entire Vatican City; give the church reparations within limits for land taken during the unification of Italy; and he would protect the church's position as the state religion of Italy. In return, the Vatican agreed to recognize Italy as a separate nation and Mussolini as the leader of Italy. A series of treaties and concordats known at the Lateran Treaty made all of this official.