Ever since Bretton Woods, the US has had the power of global leadership. During the interwar period (1919-1939), Americans were unprepared to assume that mantle; but World War II taught them the cost of isolationism, and they rose to the challenge in 1944.
我们常常耳闻硬实力（军事）和软实力（一国思想、文化、经济制度等方面的吸引力）。但还有另一种实力。自布雷顿森林以来，美国一直拥有全球领导实力。在两次大战期间（1919—1939年），美国人还没有做好承担责任的准备；但二战让他们领略了孤立主义的代价，1944年，他们终于迎难而上。