In 1899, U.S. Secretary of State John Hay wrote six world powers calling for an 'Open Door' in China that would guarantee equal trading opportunities, curtail colonial annexation, and prevent conflict in the Far East. Within a year, the region had succumbed to renewed colonisation and war, but despite the apparent failure of Hay's diplomacy, the ideal of the Open Door emerged as the central component of U.S. foreign policy in the twentieth century. Just as visions of 'Manifest Destiny' shaped continental expansion in the nineteenth century, Woodrow Wilson used the Open Door to make the case...