If a single theme pervades the history of American thinking about the world, it is that the United States has a peculiar obligation to better the lot of humanity. Call it a Puritan survival, or a sport from the Lockean roots of natural-rights philosophy, or a manifestation of American exceptionalism; but for whatever reasons, Americans have commonly spoken and acted as though the salvation of the world depended on them. From the moment John Winthrop planted his “city on a hill” as a self-conscious example for the whole world to see; through the era when the American revolutionaries cast their conflict against Britain as a blow for the unalienable rights of all men; to the day when Abraham Lincoln defended the war for the Union as a struggle to guarantee that government of the people, by the people, and for the people not perish from the (entire) earth; to the day when Woodrow Wilson called for a crusade to make the world safe for democracy; to Franklin Roosevelt's extrapolation of the Atlantic Charter to the Pacific and Indian oceans; to John Kennedy's pledge to pay any price and bear any burden in the defense of the liberty of Berlin and other Cold War hot spots; to George Bush's assertion of the need for Americans to secure a “new world order”; to Bill Clinton's dispatch of troops to Bosnia to enforce an American-brokered peace in that broken and bleeding land – which is to say, from the beginning of American history to the present – this sense of obligation to suffering humankind has been a persistent theme in American thought, speech, and writing about the world.