The leaders who formulated and implemented U.S. foreign policy during the two decades following World War II had witnessed the bitter consequences of post-Versailles isolationism, of beggar-thy-neighbor international economic policies, of military restraint in the face of rearmament by those committed to destruction of the existing international order, and of efforts to conciliate expansionist dictatorships by offering concessions. That such experiences should have shaped their thinking is neither surprising nor unprecedented in foreign policy decisionmaking. 1 The impact of these events and the “lessons” drawn from them is dramatically evident in memoirs and diaries of many post-World War II foreign policy leaders, as well as in a number of recent studies of postwar diplomacy.