The Japanese military occupation of Manchuria in late 1931 placed U.S. Secretary of State Henry L. Stimson in a difficult position. It was evident that appeals to the spirit of the Kellogg-Briand Pact had no impact on either the Chinese or the Japanese, and the secretary was further hampered by President Hoover’s clear indication that he would not support economic sanctions as a means to bring peace in the Far East. On January 7, 1932, Secretary Stimson sent identic notes to China and Japan that incorporated a diplomatic approach used by earlier secretaries facing crises in the Far East. Later known as the Stimson Doctrine, or sometimes the Hoover-Stimson Doctrine, the notes read in part as follows:
[T]he American Government deems it to be its duty to notify both the Imperial Japanese Government and the Government of the Chinese Republic that it cannot admit the legality of any situation de facto nor does it intend to recognize any treaty or agreement entered into between those Governments, or agents thereof, which may impair the treaty rights of the United States or its citizens in China, including those which relate to the sovereignty, the independence, or the territorial and administrative integrity of the Republic of China, or to the international policy relative to China, commonly known as the open door policy….Stimson had stated that the United States would not recognize any changes made in China that would curtail American treaty rights in the area and that the "open door" must be maintained. The Japanese, however, were not dissuaded by non-recognition and continued their aggression, confident that the U.S. would not take stronger action because of the strength of isolationist feeling there. By early 1932, some American newspapers were critical of the secretary’s tepid response to the Manchurian crisis, but many citizens felt that the doctrine’s idealistic, but non-threatening, tone was exactly right. Most Americans were probably far more sympathetic to China, but did not want to provoke Japan. Memories of American losses in foreign war were still fresh.