In the first two decades of the twentieth century, the relationship between the United States and Japan was marked by increasing tension and corresponding attempts to use diplomacy to reduce the threat of conflict. Each side had territory and interests in Asia that they were concerned the other might threaten. U.S. treatment of Japanese immigrants and competition for economic and commercial opportunities in China also heightened tensions. At the same time, each country’s territorial claims in the Pacific formed the basis for several agreements between the two nations, as each government sought to protect its own strategic and economic interests.
Japanese and US relations frayed at the beginning of the 20th Century
At the turn of the century, U.S. and Japanese interests appeared to be aligned. Both nations supported the idea of an “open door” for commercial expansion in China. After the Russo-Japanese War of 1904–05, U.S. President Theodore Roosevelt acted as a mediator at Japan’s request, and the two sides of the conflict met on neutral territory in Portsmouth, New Hampshire. In the same year, U.S. Secretary of War William Howard Taft met with Prime Minister Katsura Taro in Japan. The two concluded the secret Taft-Katsura Agreement, in which the United States acknowledged Japanese rule over Korea and condoned the Anglo-Japanese alliance of 1902. At the same time, Japan recognized U.S. control of the Philippines.