Every day, for example, politicians, of which there are plenty, swear eternal devotion to the ends of peace and security. They always remind me of the elder Holmes’ apostrophe to a katydid: “Thou say’st an undisputed thing in such a solemn way.” And every day statesmen, of which there are few, must struggle with limited means to achieve these unlimited ends, both in fact and in understanding. For the nation’s purposes always exceed its means, and it is finding a balance between means and ends that is the heart of foreign policy and that makes it such a speculative, uncertain business.