In a letter to the Senate Foreign Relations Committee's Republican chairman William E. Borah of Idaho, Secretary of State Henry Stimson put forth the policy of the Herbert Hoover administration regarding Japanese interference in China, reaffirming the traditional American line of equal trade for all in China and respect for Chinese sovereignty–known as the Open Door policy. The subject of the letter is the Nine-Power Treaty between the major powers of the Pacific, including the United States, Japan, and China, concluded in 1922. Stimson regards the principles of the Nine-Power Treaty and other related treaties such as the Kellogg-Briand Pact (1928) as important to uphold. However, as a response to Japanese aggression, he offers only nonrecognition of those changes that would impair Chinese sovereignty or threaten American interests in China. He does not speak of taking economic, military, or active diplomatic measures against Japan at this point.

In a letter to the Senate Foreign Relations Committee's Republican chairman William E. Borah of Idaho, Secretary of State Henry Stimson put forth the policy of the Herbert Hoover administration regarding Japanese interference in China, reaffirming the traditional American line of equal trade for all in China and respect for Chinese sovereignty–known as the Open Door policy. The subject of the letter is the Nine-Power Treaty between the major powers of the Pacific, including the United States, Japan, and China, concluded in 1922. Stimson regards the principles of the Nine-Power Treaty and other related treaties such as the Kellogg-Briand Pact (1928) as important to uphold. However, as a response to Japanese aggression, he offers only nonrecognition of those changes that would impair Chinese sovereignty or threaten American interests in China. He does not speak of taking economic, military, or active diplomatic measures against Japan at this point.

The partial disintegration of Chinese central government following the Chinese Revolution of 1911 and the overthrow of the imperial Qing dynasty had opened up opportunities for aggression by China's neighbor Japan, such as the Twenty-One Demands Japan made on China in 1915, which, among other things, strengthened Japanese control over Manchuria. Japan was taking advantage of a time when the Western powers were involved in World War I. There was a long-standing rivalry between the United States and Japan in the Pacific, which was not significantly alleviated by the two countries being allies against Germany in World War I. The Japanese were frequent targets of American racism as well.

There had been some hope of establishing friendlier relations between the United States and Japan during the early 1920s, when both countries had been signatories to the Washington Naval Treaty (or Five-Power Treaty) and the Nine-Power Treaty governing the relations of the Pacific powers. In a related treaty signed then, Japan had even returned Shandong Province, which it had taken from the Germans in World War II, to Chinese control. However, by the late 1920s, Japanese policy had once again taken a militaristic turn. Much of postrevolutionary China was under the control of warlords, opening the door to invasion. In 1931, Japan invaded the region of Manchuria in China's northeast, the traditional homeland of the Manchu people, the founders of the Qing dynasty. Japanese influence had been growing stronger there ever since Japan's victory over Russia in the Russo-Japanese War in 1905, by which, in the Treaty of Portsmouth, Japan had solidified its control over the Korean peninsula and taken control of Manchurian railroads.

The Japanese demand for economic privileges in China and attacks on Chinese sovereignty in Manchuria conflicted with the long-standing American policy of the Open Door, which called for commercial equality and the preservation of China as an independent nation. However, American involvement in World War I had led many Americans to be wary of involvement in the affairs of foreign nations, and during the Great Depression, the focus of most Americans' interest was domestic rather than foreign affairs. President Herbert Hoover shared this domestic focus and prevented Stimson from advocating more forceful measures. On January 7, 1932, Stimson sent a letter to the Chinese and Japanese governments, stating that the United States would not recognize any treaty or agreement between the two states that affected US rights in China, Chinese territorial changes, or the Open Door policy. However, given President Hoover's opposition to economic sanctions, the policy could not be enforced. Manchukuo, a Japanese puppet state in the territory of Manchuria, declared its independence from China on February 18, 1932, a few days before Stimson's letter to Borah.

American sympathy for the Chinese cause was not merely a matter of government policy, however, but was also rooted in American culture. Pearl S. Buck's epic about Chinese peasant life, The Good Earth, was the best-selling novel in the country in both 1931 and 1932. Many Americans supported the efforts of Christian missionaries in China, although Chinese immigrants in America faced much racist discrimination.

Henry Lewis Stimson (1867–1950) was a prominent lawyer, major American statesman, and Republican political figure for decades. Stimson was secretary of war during the William Howard Taft administration (1911–13) and later served as governor-general of the Philippines from 1927 to 1929. He became secretary of state in the administration of Republican president Herbert Hoover. Stimson became strongly identified with opposition to Japanese expansion in China, formulating the Stimson Doctrine that the United States would not recognize territorial changes that impinge on US treaty rights or are brought about by aggression. As secretary of war again in World War II, he played a major role in the American decision to drop atomic bombs on the Japanese cities of Hiroshima and Nagasaki. Stimson retired in September 1945.

The letter is a statement of administration policy in the waning days of the Hoover administration, before the presidency passed to Franklin D. Roosevelt. (Presidents were inaugurated on March 4 before the Twentieth Amendment went into effect in 1933, moving the date to January 20.) Stimson states the opposition of the United States to territorial changes achieved by force and support of the Open Door to China, the American policy by which all countries were to have equal rights to trade with China. The growing desire of Japan to exert economic hegemony over China was a threat to the Open Door and specifically to US trade with China. Although the letter is addressed specifically to Senator Borah, it was published almost immediately and Stimson likely wrote it with a public audience in mind. Borah was generally regarded as an isolationist, who had opposed American entry into the League of Nations following World War I and was wary of American involvement in European affairs. However, like many American isolationists, he was more willing for the United States to take a strong position in the Asia-Pacific region than in Europe.

Stimson first recapitulates the history of American diplomatic involvement in China, the Open Door policy, and the Nine-Power Treaty, which Stimson viewed as embodying the Open Door policy. He emphasizes that not only the United States, but the world's other preeminent maritime power, the British Empire, endorsed this policy, putting it forth as a consensus position rather than a purely American policy. The Nine-Power Treaty was part of a complex of international agreements, including the Washington Naval Treaty, which demilitarized much of the Pacific and guaranteed the independence of China. This position was reinforced and partially globalized with the adoption of the Kellogg-Briand Pact six years later, which set the face of the international community against territorial aggrandizement by force and aggression. Stimson argues that the recent threat to the treaty caused by conflict between China and Japan (and he is careful not to lay blame on one party) only means that the terms of these treaties, and the international order based on them, need further support. The difficulty was how the treaties, which contained little in the way of enforcement mechanisms, could be upheld. The possibility of enforcement through the League of Nations is not mentioned, as the United States was not a member.

What Stimson offers as a response to Japanese aggression in China is American nonrecognition of those changes that threatened Chinese sovereignty or American rights in China. However, he offers nothing beyond that in the way of either economic sanctions against Japan (which Hoover opposed), aid to China, or military action.

American opposition to Japanese expansion and support of the Open Door policy in China continued into the Democratic administration of Franklin Delano Roosevelt, when the Republican Stimson was replaced by Democrat Cordell Hull as secretary of state. Despite Hull's efforts to keep peace between the United States and Japan while opposing Japanese imperialism, the conflict intensified with the actual breakout of war between Japan and China in 1937. The broader principle regarding the territorial acquisition by force was also challenged by the expansionist power of Nazi Germany and Fascist Italy. The growing power of the aggressor states and their disregard for the political order set up in the 1920s led to the adoption of more active policies to oppose them, such as the embargo that the Roosevelt administration eventually imposed on Japan. Growing hostility between the United States and Japan culminated in the Japanese attack on Pearl Harbor on December 7, 1941, and American entrance into World War II. Stimson himself, as secretary of war during World War II, was a strong advocate of using nuclear weapons on the Japanese population.

Along with the League of Nations, the United States refused to give diplomatic recognition to Manchukuo, the puppet state the Japanese had carved out of China. The policy of not recognizing territorial changes made by force is sometimes referred to as the Stimson Doctrine and remains part of US policy, although, in practice, its application has been flexible. The same doctrine applied to the US nonrecognition of the Soviet annexation of the Baltic States (Latvia, Lithuania, and Estonia) during World War II, and was a policy maintained throughout the Cold War.

• Fairbank, John K.The United States and China. 4th ed. Cambridge: Harvard UP, 1983. Print.
• Hodgson, Geoffrey.The Colonel: The Life and Wars of Henry Stimson, 1867–1950. New York: Knopf, 1990. Print.
• Jeansonne, Glen.The Life of Herbert Hoover: Fighting Quaker, 1928–1933. New York: Palgrave, 2012. Print.