In March 1938, during a stay in London, she learned of the occupation of Austria by Nazi Germany. Karl Bühler was taken into "protective custody" on March 23, 1938 due to his vocal anti-Nazi sentiments. Via connections in Norway, Charlotte Bühler arranged the release of her husband after six and a half weeks, and in October 1938 the family was reunited in Oslo. Because Charlotte Bühler was of Jewish descent they emigrated to the United States.