The primary aim of the United States Open Door Policy was to ensure that all countries had equal access to trade with China. The policy was announced by U.S. Secretary of State John Hay in 1899, in response to the growing rivalry between the European powers for control of China.
The Open Door Policy was based on the principle of "equal opportunity" for all countries in China. This meant that no one country could have exclusive economic or political privileges in China. The policy also called for the preservation of China's territorial integrity and independence.
The Open Door Policy was a major success in preventing a war between the European powers over China. It also helped to promote trade and economic development in China. However, the policy was not without its critics. Some people argued that the policy was a form of imperialism, and that it did not take into account the interests of the Chinese people.
Despite its critics, the Open Door Policy remained in effect until the end of the Chinese Civil War in 1949. The policy was a major factor in the development of China into a modern nation.