The United States tried to approach Korea in the middle of the 19th century when the ""East Asian International System,"" which positioned China in the center began to collapse owing to the entering of Europe and America to the East Asia region and the rise of Japan. After the opening of Japan to Europe and America, the United States approached Korea several times in the 1860s and 1870s, not so much because it valued Korea as because it had a kind of ""challenge spirit,"" with which it wanted to correct the posture of Korea from maintainining its isolation from the rest of the world. Therefore, after successfully concluding the ""Treaty of Amity and Commerce between the United States of America and Corea"" in 1882, the United States changed her attitude to ""Indifference."" It did so because it maintained the traditional ""Monroe Doctorine"" of nonintervention policy and did not want to engage deeply with the political issues of Korea, in which Japan, China and Russia had much interest. The United States had little interest in the nation from economical standpoint. On the other hand, Korea maintained its national isolation policy because of a kind of ""Little Sinocetrism,"" even after China, a suzerain state of Korea, opened itself to Europe and America. But while Japan tried to reverse its relations with Korea of the Tokugawa Era in which Korea served as a teacher, after the Meiji Restration, Korea tried to strengthen its dependence on the United States from the standpoint of ""Idealism."" This was because it was not fully confident of its own ability to defend itself and also because of the relatively favorable content of the U.S. -Korean Treaty of 1882 as well as the less concern it had for the United States, which was far away from East Asia and had no colony in the area. But the United States assumed a ""realistic"" attitude toward Korea because of its ""Imperializing"" issues, symbolized by the annexation of Hawaii and the Philippines as well as aforesaid reasons. And the discord between the American ""realism"" and the Korean ""idealism,"" originated from the period when Korea was opened to the United States, led to the ""Passing of Korea"" because the President Theodore Roosevelt, imperialistic and realistic, strongly supported the Japanese protectorate over Korea. He gave a tacit consent to the Second Japanese-Korea Agreement of 1905 and rejected all the Korean requests to exert his good offices according to the Article I of the U.S. -Korean Treaty of 1882.