Samuel P. Huntington. 1996. The Clash of Civilizations and the Remaking of World Order. New York: Simon & Schuster. Chapter 1 §1‐2 (“The New Era in World Politics”); Chapter 2 §1 (“Civilizations in History and Today”); and Chapter 6 (“The Cultural Reconfiguration of Global Politics”).
A civilization is the broadest cultural identity. Civilizations evolve and endure.
Cultural identity defines a state's place in world politics, its friends, and its enemies. Modernization after the Cold War has reconfigured global politics along cultural lines. Cultural commonality facilitates cooperation and cohesion among people and cultural differences promote cleaves and conflicts.
Cleft countries bestride the fault lines between civilizations. A torn coutry has a single predominant culture which places it in one civilization but its leaders want to shift it to another civilization.