When the Berlin Wall collapsed and the Cold War ended on November 9, 1989, the West declared victory: democracy and free markets had prevailed and the United States emerged as the triumphant superpower. The tension that had defined a generation was over, and it seemed that peace was at hand. When September 11, 2001, set the U.S. on a new path, confused Americans asked: How did we get here? Foreign policy experts Chollet and Goldgeier examine how the...