How did Eugenio Pacelli contribute to the anti-Nazi encyclical Mit brennender Sorge?

Eugenio Pacelli, who later became Pope Pius XII, served as the principal adviser to Pope Pius XI regarding Adolf Hitler and the Nazi regime. At the pope's command, Pacelli helped draft the anti-Nazi encyclical Mit brennender Sorge ("With Deep Anxiety"), which was addressed to the German church on March 14, 1937.1

The document condemned racial theories and the mistreatment of individuals based on their race or nationality, though it notably avoided naming Hitler or the Nazis directly. While Pacelli contributed to this encyclical, it is important to note that for a separate, later project—an encyclical intended to demonstrate the incompatibility of Catholicism and racism—Pius XI specifically excluded Pacelli from the drafting process. The pope took this step because he was aware of Pacelli’s strong desire to avoid a break in diplomatic relations between the Vatican and Berlin.1