During the period after Nazi Germany and the Soviet Union had signed the Molotov–Ribbentrop non-aggression pact, most American Communists were opposed to the United States entering World War II, and they tried to infiltrate or take over America First. After June 1941, when Hitler launched Operation Barbarossa, the invasion of the Soviet Union, they reversed positions and denounced the AFC as a Nazi front, a group infiltrated by German agents. Nazis also tried to use the committee; at the trial of the aviator and orator Laura Ingalls, the prosecution revealed that her handler, German diplomat Ulrich Freiherr von Gienanth, had encouraged her to participate in committee activities.