fracturing of ancient China during the Spring and Autumn era or in the Roman Empire in the age of the Caesars. Our current shifting - that tap, tap on every nation’s politics, media, and economics - isn’t really so unpredictable after all. 242 You may know the old saw of military parade evaluation: That the more magnificent a nation’s uniforms are the weaker it’s army usually is. But the gold-braided admirals of some three-ship navy reflect a very human need for security, and particularly for a self-decided feeling of security. Every nation has it’s own foreign affairs aims. Each cherishes a certain national image, memories of military glory and of “interests” inseparable from culture or identity. The goals of the French and the Turks, for instance, each evoke an encyclopedia of history, tradition and politics. Uneasiness in Paris about capitalism and immigration, for instance; or Anrka’s worry about ethnic division, fundamentalisms, and the creeping nuclear progress of their neighbors. Our era’s revolutionary logic will shape choices in every nation differently. But I'd like here to discuss American foreign policy. America plays a central role in world order now. The country’s leading position makes her, to some degree, an unavoidable gatekeeper. In the Napoleonic era, nearly every revolution or war could be tied to energies emanating from Paris. During the Cold War most puzzles of politics or geography might be framed in terms of a zero-sum competition with the USSR. In our own age, we'll find most every problem links to networks and their new logic. And - for now at least - to America. Thomas Paine’s memorable 250 year-old assessment, that “The cause of America is the cause of all mankind,” touches this linked universalism in a way he never could have imagined. “Betweeness” or “Centrality” are the way network science labels and measures such a role. Just how essential is a certain nation or trading platform or point? The networks of America won't, in the future,