Secretary of State John Hay's announcement of the Open Door Policy marked a pivotal moment in international trade relations with China. During the late 19th century, China was undergoing a period of fragmentation and foreign intervention, with various nations vying for control and influence over different territories. To prevent the division of China into colonies and to promote equal commercial opportunities for all nations, the Open Door Policy was articulated. Hay's note, sent in September 1899, called for the preservation of China's territorial integrity and the maintenance of equal trading rights for all foreign nations. The response to Hay's initial note was lackluster, leading to a second note in 1900 restating these principles, as the Boxer Rebellion further complicated the situation.

The Boxer Rebellion, which sought to expel foreign influence from China, heightened tensions among foreign powers. As various nations took military action to protect their interests, Hay's advocacy for an Open Door Policy became increasingly relevant. The United States sought to position itself as a crucial player in international diplomacy and trade. Through this policy, Hay aimed not only to secure U.S. access to Chinese markets but also to contribute to a multilateral approach to foreign affairs and uphold the principle of equal trade opportunities.

Hay's Open Door Policy was later acknowledged as a cornerstone of U.S.-China relations. It established a framework for American diplomatic efforts in East Asia and highlighted the significance of maintaining open markets as a strategy for avoiding conflict. The policy was reaffirmed in subsequent years and shaped American interactions with China well into the 20th century, representing an early example of the United States’ growing interest in international trade dynamics and its assertive stance in foreign policy.