The Vatican worried that an influx of Jewish refugees into Palestine would create a situation that would be detrimental to the concerns of the Church. Palestine was home to the holy places such as the Church of the Holy Sepulchre in Jerusalem, the Church of the Nativity in Bethlehem and the Mount of Beatitudes in Galilee. A Jewish majority in what was the British-governed Mandate was not desirable. It would cause grave offence to Catholic piety and even worse, outshine Vatican efforts to help the Jews get out of Europe in the first place. Pius XII understood the arguments and agreed with them. He would not support a Jewish homeland in Palestine.
Between March and May 1943 there are several documents in ADSS 9 that show without any doubt the resistance to the idea of Palestine becoming a Jewish home. There is agreement that the Jews should have a national home; as long as it was not in Palestine.
On 12 May 1917 the Secretary of State, Cardinal Gasparri and the young Monsignor Pacelli met Nahum Sokolow, president of the World Zionist Organisation and listened to his ideas for a Jewish Homeland in Palestine. Sokolow recorded the meeting as being positive and friendly. Things changed less than six months later with the British announcement of the Balfour Declaration of 2 November 1917. Polite and cordial meetings in the Vatican between two sides that had no power to change the political realities of Palestine were one thing, the announcement of the British government to support a Jewish Homeland in Palestine and the political and military power that underpinned the statement, were quite another. Pope Benedict XV was opposed to the idea of Jewish home for the reasons cited above. Fear of Jewish domination and, worse, the fear of Jews having political power over Christians, led the pope to declare his, and the Church's official opposition to any attempt to create a Jewish state in Palestine. The attitude was not change until well after the creation of the State of Israel in 1948.
Let us look at the documents in ADSS 9.
ADSS 9.94: 13.03.1943 The Apostolic Delegate in London, William Godfrey, sent news to Rome that the British government was willing to permit Jewish children passage to Palestine. Notes made by Domenico Tardini included references to the Holy See's long known opposition to the creation of Jewish home and the bald statement that the Holy Land was more holy to Catholics than Jews!
ADSS 9.171 04.05.1943 Cardinal Maglione wrote to Godfrey to say that the Holy See has done and is doing everything to help the Jews. However, as the Apostolic Delegate would well remember, the British government's pledge in the Balfour Declaration was not in the interest of Catholics who would be offended if Palestine was to be exclusively Jewish.
ADSS 9.191 18.05.1943 Maglione wrote to Amleto Cicognani, Apostolic Delegate in Washington with instructions to protest any and all attempts to create a Jewish homeland in Palestine. The forceful language borders on the undiplomatic. The idea of bringing a people back to a land after nineteen centuries makes no sense. Catholics will be outraged. The Holy See is doing everything it can to help the Jews.
ADSS 9.324 04.09.1943 Angelo Roncalli, Apostolic Delegate in Turkey to Cardinal Maglione expressed his reservations over Jewish migration to Palestine as if they were going to reconstruct a biblical-like kingdom. These were dreams and not realities. Roncalli did confess that perhaps his reservations were personal scruples that he had not been able to disperse.
There is an awful inference in these documents. The Holy See was doing everything it could to help and rescue the Jews of Europe so the Jews should not seek to emigrate to Palestine and upset Catholic sensibilities. And it was the pope who maintained the official stance opposing Jewish migration that had been adopted by his predecessor Benedict XV in late 1917.
Between January and March 1943 approximately 105,000 Jews were murdered at Auschwitz-Birkenau. Between 1939 and 1945 73,764 Jews managed to reach Palestine. The Vatican's fears of Jewish domination in the Mandate were at best nonsensical and at worst a manifestation of old fashioned supercessionism and Judeophobia.