This is particularly important now when Pius XII is being considered for beatification and in the face of horrible slanders and libels being perpetrated against him. From the start, he vigorously opposed Nazism and Fascism and only a perverted reading of the historical record can say otherwise.
Might be worth a Catholic ping
Sorry, but that's simply not factually true. In fact the Vatican under both Piuses XI and XII signed concordats and made peace with fascists like Mussolini and Franco. So fascism itself was no particular problem for the Vatican.
In 1933 they expected the same from their Concordat with Hitler's Nazis. In exchange for Hitler's promise not to molest the Church, the Vatican agreed to disband Germany's opposition Catholic political party. Now, take a minute to consider just what that deal meant.
Of course, Hitler did not live up to his promises, and so the Vatican was sometimes forced to speak in opposition. But it NEVER took SERIOUS steps against Nazism, such as excommunicating Nazis, or even Hitler himself!
Indeed, even on his death by suicide, Hitler was given a Catholic mass.
So, yes, the Vatican did oppose Hitler's Nazism, but it was a weak and totally ineffective opposition, imho. By contrast, the Vatican displayed no such weaknesses in opposing Stalin's Communism.