In 1906, following Japan's victory in the in the Russo-Japanese War, San Francisco required children of Japanese descent to attend racially segregated schools. In 1931, after the annexation of Manchuria, many American citizens called for American economic intervention to pressure Japan to leave China. In 1937, with the onset of the Second Sino-Japanese War and the Nanking Massacre, the majority of Western public opinion was strongly in favor of China.