There has never been a true “world order,” Kissinger observes. For most of history, civilizations defined their own concepts of order. Each considered itself the center of the world and envisioned its distinct principles as universally relevant. China conceived of a global cultural hierarchy with the emperor at its pinnacle. In Europe, Rome imagined itself surrounded by barbarians; when Rome fragmented, European peoples refined a concept of an equilibrium of sovereign states and sought to export it across the world. Islam, in its early centuries, considered itself the world’s sole legitimate political unit, destined to expand indefinitely until the world was brought into harmony by religious principles. The United States was born of a conviction about the universal applicability of democracy—a conviction that has guided its policies ever since.