Hay proposed a free, open market and equal trading opportunity for merchants of all nationalities operating in China, based in part on the most favored nation clauses already established in the Treaties of Wangxia and Tianjin. Hay argued that establishing equal access to commerce would benefit American traders and the U.S. economy, and hoped that the Open Door would also prevent disputes between the powers operating in China. For the United States, which held relatively little political clout and no territory in China, the principal of non-discrimination in commercial activity was particularly important. Hay called for each of the powers active in China to do away with economic advantages for their own citizens within their spheres of influence, and also suggested that the Chinese tariffs apply universally and be collected by the Chinese themselves. Although the other powers may not have agreed fully with these ideas, none openly opposed them.
In 1900, however, internal events in China threatened the idea of the Open Door. An anti-foreign movement known as the Boxer Rebellion, named for the martial artists that led the movement, gathered strength, and began attacking foreign missionaries and Chinese converts to Christianity. With the backing of Empress Dowager Cixi (Tz’u Hsi) and the imperial army, the Boxer Rebellion turned into a violent conflict that claimed the lives of hundreds of foreign missionaries and thousands of Chinese nationals. As the Boxers descended upon Beijing, foreign nationals living in that city--including embassy staff--clustered together in the besieged foreign legations, and called upon their home governments for assistance.
Together, the Open Door Notes served the important purpose of outlining U.S. policy toward China and expressing U.S. hopes for cooperation with the other foreign powers with a stake in the region. They were of lasting importance in U.S.-East Asian relations, and contributed to the idea of a Sino-American “special relationship.” However, because they were non-binding, the Notes did not prevent the United States--or any other power--from one day seeking Chinese territory, or acting in any way that was preferential to their own interests, even at the expense of the Chinese Government. Hay himself even briefly considered a seizure of Chinese territory, although he quickly rejected the idea. Although the Notes were not binding, Hay’s successors nonetheless adhered to the policy of maintaining the Open Door in China. The articulation of the Open Door policy represented the growing American interest and involvement in East Asia at the turn of the century.
Ironically, Hay articulated the Open Door policy at a time when the U.S. Government was doing everything in its power to close the door on Chinese immigration to the United States. This effectively stifled opportunities for Chinese merchants and workers in the United States. (See Chinese Immigration and the Chinese Exclusion Acts.)