This was the mission of Soviet "active measures" in the West. Here's [UPDATE: my original link went bad, but you can find the story at zenit.org in their June 13th dispatch] evidence that they were the originators of the calumnies against Pope Pius XII. Usually this "black legend" is attributed to Rolf Hochhuth's 1963 play The Deputy, but if this story is true, the KGB was spreading it 20 years beforehand.
Hmm. This requires further digging, but it makes me wonder if Hochhuth was himself a Communist --the Swiss version of Dalton Trumbo?. (The point of The Deputy is that Pius was so focused on his fear of Communism that he didn't do anything to help the Jews during WWII, and isn't it silly to be afraid of Communism?)
Here are two defenses of Pius XII, fyi. Michael Novak's and my favorite: Rabbi David Dalin's.
