Events in China drew the United States ever deeper into the politics of the western Pacific, largely as the consequence of another moral crusade. After 1897, China's political and military weakness exposed it to foreign encroachments that threatened to reduce it to colonial status. The McKinley administration, through Secretary of State John Hay's Open Door Notes of 1899 and 1900, saved China from further disintegration. In the process, however, the United States assumed an immense, if informal, obligation to defend the commercial and administrative integrity of China. For its adherents, these apparently cost-free obligations comprised not a burden, but a remarkable triumph for American humanitarian principles. Some observers hailed Hay's achievement equal to those of the country's greatest nineteenth-century diplomats. Senator Shelby M. Cullom of Illinois offered a characteristic eulogy: "The magnitude of the man [Hay] will only appear in the magnitude of his work when it reaches its colossal proportions in the proper perspective of the past." Much of the press lauded the secretary for his momentous success. The New York Journal of Commerce called the Open Door episode "one of the most important diplomatic negotiations of our time." The Nation praised the Open Door policy as a great national triumph. "Our intervention in China," ran its conclusion, "has given the world a transcendent exhibition of American leadership in the world of ideas and the world of action. We have proved that we are guided by a diplomacy unsurpassed…in its patient moderation, its firmness, its moral impulse."
Others explained why Hay's apparent achievements on behalf of China carried the seeds of disaster. Like the acquisition of the Philippines, Hay's easy successes confirmed the illusion that the United States could have its way in Asia at little or no cost to itself. Realistic observers noted, however, that Hay's diplomacy either had committed the United States to the use of force in a distant, disorganized region of the Far East, or it had achieved nothing; no nation would have compromised its essential interests in China merely at Hay's request. "Diplomacy has done nothing to change the situation," warned the Springfield Republican, "while the Government has gone far toward placing itself in a position where, to be consistent, it must guarantee by military force the territorial integrity of China, or share in its possible partition." Similarly, Alfred Thayer Mahan observed in November 1900 that the United States could not "count on respect for the territory of China unless we are ready to throw not only our moral influence but, if necessity arise, our physical weight into the conflict." Mahan noted that both Russia and Japan, the two dominant powers in the Far East, had far greater interests in China than did the United States. The Open Door policy, by establishing a powerful and exaggerated American concern for the commercial and territorial integrity of China, rendered any country that might interfere in Chinese affairs the potential enemy of the United States.