Maximilian: This is a big accusation. What evidence do you have for it?
As written by Mary Ball Martinez:
The Soviet Factor
Papal preference for the Allied side became more difficult to defend after June 1941, when this became the Soviet side. By that time Hitler's "Fortress Europe" was overwhelmingly Catholic. Germany itself then included the predominantly Catholic regions of Austria, the Saarland, and the Sudetenland, as well as Alsace-Lorraine and Luxembourg. Moreover, the German-allied countries of Italy, Slovenia, Slovakia and Croatia were entirely Catholic, and Hungary was mainly so. France -- including both the German-occupied northern zone and the Vichy-run south -- cooperated with Germany. Similarly, Catholic Spain and Portugal were sympathetic.
A Catholic priest, Josef Tiso, had been elected president of the German-backed Republic of Slovakia. In France, which adopted the Axis ban on Freemasonry, crucifixes went up on all public buildings, and on French coins the old official motto of the French Revolution, "Liberty, Equality, Fraternity," was replaced with "Family, Fatherland, Work."
Thus, Pope Pius XII found himself in the awkward position of siding with atheistic Soviet Russia, overwhelmingly Protestant Britain (with its vast, mainly non-Christian Empire), and the predominantly Protestant United States of America, against the largely Catholic "Fortress Europe." His predicament reached a climax following the December 1941 attack on Pearl Harbor, and America's full entry into the world war. Most Catholic Americans -- including those of Italian, Irish, German, Hungarian, Slovenian, Croatian and Slovakian descent -- had regarded themselves as "isolationists." Furthermore, Communist atrocities against priests, nuns and churches during the Spanish Civil War (1936-1939) were fresh in their minds.
Skilled diplomat that he was, Pius XII met the challenge. He appointed the dynamic young Auxiliary Bishop of Cleveland, Michael Ready, to head a campaign to "reinterpret" Divini Redemptoris, the anti-Marxist encyclical of the previous Pope, Pius XI, and to put out the word that Soviet dictator Stalin was opening the way to religious freedom in the USSR.
The Pope's Wartime Silence
That it cost something for the head of the Catholic Church to face so many millions of European Catholics as an enthusiastic supporter of their enemies is evident from a poignant letter Pacelli wrote to Myron C. Taylor, who had been his host in New York and was now Roosevelt's envoy to the Holy See. In part, "at the request of President Roosevelt, the Vatican has ceased all mention of the Communist regime. But this silence that weighs heavily on our conscience, is misunderstood by the Soviet leaders who continue the persecution against churches and faithful. God grant that the free world will not one day regret my silence." There was indeed a "silence of Pius XII," but it was not the silence invented by Hochhuth and Friedlander.
GGII: Bottom line: had he done what the Blessed Mother requested, the couse of events leading up to WWII might have been dramatically different. I'll get back to you later on the other questions you raise.