Due to his years in the Philippines, Taft was keenly interested as president in East Asian affairs. Taft considered relations with Europe relatively unimportant, but because of the potential for trade and investment, Taft ranked the post of minister to China as most important in the Foreign Service. Knox did not agree, and declined a suggestion that he go to Peking to view the facts on the ground. Taft considered Roosevelt's minister there, William W. Rockhill, as uninterested in the China trade, and replaced him with William J. Calhoun, whom McKinley and Roosevelt had sent on several foreign missions. Knox did not listen to Calhoun on policy, and there were often conflicts. Taft and Knox tried unsuccessfully to extend John Hay's Open Door Policy to Manchuria.